IDLWAVE User Manual

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IDLWAVE is a package which supports editing source code written in the Interactive Data Language (IDL), and running IDL as an inferior shell.

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1 Introduction

IDLWAVE is a package which supports editing source files written in the Interactive Data Language (IDL1 ), and running IDL as an inferior shell2. It is a feature-rich replacement for the IDLDE development environment included with IDL, and uses the full power of Emacs to make editing and running IDL programs easier, quicker, and more structured.

IDLWAVE consists of two main parts: a major mode for editing IDL source files (idlwave-mode) and a mode for running the IDL program as an inferior shell (idlwave-shell-mode). Although one mode can be used without the other, both work together closely to form a complete development environment. Here is a brief summary of what IDLWAVE does:

IDLWAVE is the distant successor to the idl.el and idl-shell.el files written by Chris Chase. The modes and files had to be renamed because of a name space conflict with CORBA’s idl-mode, defined in Emacs in the file cc-mode.el.

In this manual, each section ends with a list of related user options. Don’t be confused by the sheer number of options available: in most cases the default settings are just fine. The variables are listed here to make sure you know where to look if you want to change anything. For a full description of what a particular variable does and how to configure it, see the documentation string of that variable (available with C-h v). Some configuration examples are also given in the appendix.

2 IDLWAVE in a Nutshell

Editing IDL Programs

TABIndent the current line relative to context.
C-M-\Re-indent all lines in the current region.
C-M-qRe-indent all lines in the current routine.
C-u TABRe-indent all lines in the current statement.
M-RETStart a continuation line, splitting the current line at point.
M-;Start new comment at line beginning or after code, or (un)comment highlighted region.
M-qFill the current comment paragraph.
C-c ?Display calling sequence and keywords for the procedure or function call at point.
M-?Load context sensitive online help for nearby routine, keyword, etc.
M-TABComplete a procedure name, function name or keyword in the buffer.
C-c C-iUpdate IDLWAVE’s knowledge about functions and procedures.
C-c C-vVisit the source code of a procedure/function.
C-u C-c C-vVisit the source code of a procedure/function in this buffer.
C-c C-hInsert a standard documentation header.
C-c RETInsert a new timestamp and history item in the documentation header.

Running the IDLWAVE Shell, Debugging Programs

C-c C-sStart IDL as a subprocess and/or switch to the shell buffer.
Up, M-pCycle back through IDL command history.
Down,M-nCycle forward.
TABComplete a procedure name, function name or keyword in the shell buffer.
C-c C-d C-cSave and compile the source file in the current buffer.
C-c C-d C-eCompile and run the current region.
C-c C-d C-xGo to next syntax error.
C-c C-d C-vSwitch to electric debug mode.
C-c C-d C-bSet a breakpoint at the nearest viable source line.
C-c C-d C-dClear the nearest breakpoint.
C-c C-d [Go to the previous breakpoint.
C-c C-d ]Go to the next breakpoint.
C-c C-d C-pPrint the value of the expression near point in IDL.

Commonly used Settings in .emacs

;; Change the indentation preferences
;; Start autoloading routine info after 2 idle seconds
(setq idlwave-init-rinfo-when-idle-after 2)
;; Pad operators with spaces
(setq idlwave-do-actions t
      idlwave-surround-by-blank t)
;; Syntax Highlighting
(add-hook 'idlwave-mode-hook 'turn-on-font-lock)
;; Automatically start the shell when needed
(setq idlwave-shell-automatic-start t)
;; Bind debugging commands with CONTROL and SHIFT modifiers
(setq idlwave-shell-debug-modifiers '(control shift))

3 Getting Started (Tutorial)

3.1 Lesson I: Development Cycle

The purpose of this tutorial is to guide you through a very basic development cycle using IDLWAVE. We will paste a simple program into a buffer and use the shell to compile, debug and run it. On the way we will use many of the important IDLWAVE commands. Note, however, that IDLWAVE has many more capabilities than covered here, which can be discovered by reading the entire manual, or hovering over the shoulder of your nearest IDLWAVE guru for a few days.

It is assumed that you have access to Emacs with the full IDLWAVE package including online help (see Installation). We also assume that you are familiar with Emacs and can read the nomenclature of key presses in Emacs (in particular, C stands for CONTROL and M for META (often the ALT key carries this functionality)).

Open a new source file by typing:

C-x C-f RET

A buffer for this file will pop up, and it should be in IDLWAVE mode, indicated in the mode line just below the editing window. Also, the menu bar should contain ‘IDLWAVE’.

Now cut-and-paste the following code, also available as in the IDLWAVE distribution.

function daynr,d,m,y
  ;; compute a sequence number for a date
  ;; works 1901-2099.
  if y lt 100 then y = y+1900
  if m le 2 then delta = 1 else delta = 0
  m1 = m + delta*12 + 1
  y1 = y * delta
  return, d + floor(m1*30.6)+floor(y1*365.25)+5

function weekday,day,month,year
  ;; compute weekday number for date
  nr = daynr(day,month,year)
  return, nr mod 7

pro plot_wday,day,month
  ;; Plot the weekday of a date in the first 10 years of this century.
  years = 2000,+indgen(10)
  wdays = intarr(10)
  for i=0,n_elements(wdays)-1 do begin
      wdays[i] =  weekday(day,month,years[i])
  plot,years,wdays,YS=2,YT="Wday (0=Sunday)"

The indentation probably looks funny, since it’s different from the settings you use, so use the TAB key in each line to automatically line it up (or, more quickly, select the entire buffer with C-x h, and indent the whole region with C-M-\). Notice how different syntactical elements are highlighted in different colors, if you have set up support for font-lock.

Let’s check out two particular editing features of IDLWAVE. Place the cursor after the end statement of the for loop and press SPC. IDLWAVE blinks back to the beginning of the block and changes the generic end to the specific endfor automatically (as long as the variable idlwave-expand-generic-end is turned on; see Lesson II: Customization). Now place the cursor in any line you would like to split and press M-RET. The line is split at the cursor position, with the continuation ‘$’ and indentation all taken care of. Use C-/ to undo the last change.

The procedure plot_wday is supposed to plot the day of the week of a given date for the first 10 years of the 21st century. As in most code, there are a few bugs, which we are going to use IDLWAVE to help us fix.

First, let’s launch the IDLWAVE shell. You do this with the command C-c C-s. The Emacs window will split or another window will popup to display IDL running in a shell interaction buffer. Type a few commands like print,!PI to convince yourself that you can work there just as well as in a terminal, or the IDLDE. Use the arrow keys to cycle through your command history. Are we having fun now?

Now go back to the source window and type C-c C-d C-c to compile the program. If you watch the shell buffer, you see that IDLWAVE types ‘.run ""’ for you. But the compilation fails because there is a comma in the line ‘years=...’. The line with the error is highlighted and the cursor positioned at the error, so remove the comma (you should only need to hit Delete!). Compile again, using the same keystrokes as before. Notice that the file is automatically saved for you. This time everything should work fine, and you should see the three routines compile.

Now we want to use the command to plot the day of the week on January 1st. We could type the full command ourselves, but why do that? Go back to the shell window, type ‘plot_’ and hit TAB. After a bit of a delay (while IDLWAVE initializes its routine info database, if necessary), the window will split to show all procedures it knows starting with that string, and plot_wday should be one of them. Saving the buffer alerted IDLWAVE about this new routine. Click with the middle mouse button on plot_wday and it will be copied to the shell buffer, or if you prefer, add ‘w’ to ‘plot_’ to make it unambiguous (depending on what other routines starting with ‘plot_’ you have installed on your system), hit TAB again, and the full routine name will be completed. Now provide the two arguments:


and press RET. This fails with an error message telling you the YT keyword to plot is ambiguous. What are the allowed keywords again? Go back to the source window and put the cursor into the “plot” line and press C-c ?. This shows the routine info window for the plot routine, which contains a list of keywords, along with the argument list. Oh, we wanted YTITLE. Fix that up. Recompile with C-c C-d C-c. Jump back into the shell with C-c C-s, press the UP arrow to recall the previous command and execute again.

This time we get a plot, but it is pretty ugly: the points are all connected with a line. Hmm, isn’t there a way for plot to use symbols instead? What was that keyword? Position the cursor on the plot line after a comma (where you’d normally type a keyword), and hit M-Tab. A long list of plot’s keywords appears. Aha, there it is, PSYM. Middle click to insert it. An ‘=’ sign is included for you too. Now what were the values of PSYM supposed to be? With the cursor on or after the keyword, press M-? for online help (alternatively, you could have right clicked on the colored keyword itself in the completion list). A browser will pop up showing the HTML documentation for the PYSM keyword. OK, let’s use diamonds=4. Fix this, recompile (you know the command by now: C-c C-d C-c), go back to the shell (if it’s vanished, you know what to do: C-c C-s) and execute again. Now things look pretty good.

Let’s try a different day. How about April fool’s day?


Oops, this looks very wrong. All April Fool’s days cannot be Fridays! We’ve got a bug in the program, perhaps in the daynr function. Let’s put a breakpoint on the last line there. Position the cursor on the ‘return, d+...’ line and press C-c C-d C-b. IDL sets a breakpoint (as you see in the shell window), and the break line is indicated. Back to the shell buffer, re-execute the previous command. IDL stops at the line with the breakpoint. Now hold down the SHIFT key and click with the middle mouse button on a few variables there: ‘d’, ‘y’, ‘m’, ‘y1’, etc. Maybe d isn’t the correct type. CONTROL-SHIFT middle-click on it for help. Well, it’s an integer, so that’s not the problem. Aha, ‘y1’ is zero, but it should be the year, depending on delta. Shift click ‘delta’ to see that it’s 0. Below, we see the offending line: ‘y1=y*delta...’ the multiplication should have been a minus sign! Hit q to exit the debugging mode, and fix the line to read:

y1 = y - delta

Now remove all breakpoints: C-c C-d C-a. Recompile and rerun the command. Everything should now work fine. How about those leap years? Change the code to plot 100 years and see that every 28 years, the sequence of weekdays repeats.

3.2 Lesson II: Customization

Emacs is probably the most customizable piece of software ever written, and it would be a shame if you did not make use of this to adapt IDLWAVE to your own preferences. Customizing Emacs or IDLWAVE is accomplished by setting Lisp variables in the .emacs file in your home directory—but do not be dismayed; for the most part, you can just copy and work from the examples given here.

Let’s first use a boolean variable. These are variables which you turn on or off, much like a checkbox. A value of ‘t’ means on, a value of ‘nil’ means off. Copy the following line into your .emacs file, exit and restart Emacs.

(setq idlwave-reserved-word-upcase t)

When this option is turned on, each reserved word you type into an IDL source buffer will be converted to upper case when you press SPC or RET right after the word. Try it out! ‘if’ changes to ‘IF’, ‘begin’ to ‘BEGIN’. If you don’t like this behavior, remove the option again from your .emacs file and restart Emacs.

You likely have your own indentation preferences for IDL code. For example, some may prefer to indent the main block of an IDL program slightly from the margin and use only 3 spaces as indentation between BEGIN and END. Try the following lines in .emacs:

(setq idlwave-main-block-indent 1)
(setq idlwave-block-indent 3)
(setq idlwave-end-offset -3)

Restart Emacs, and re-indent the program we developed in the first part of this tutorial with C-c h and C-M-\. You may want to keep these lines in .emacs, with values adjusted to your liking. If you want to get more information about any of these variables, type, e.g., C-h v idlwave-main-block-indent RET. To find which variables can be customized, look for items marked ‘User Option:’ throughout this manual.

If you cannot seem to master this Lisp customization in .emacs, there is another, more user-friendly way to customize all the IDLWAVE variables. You can access it through the IDLWAVE menu in one of the .pro buffers, menu item Customize->Browse IDLWAVE Group. Here you’ll be presented with all the various variables grouped into categories. You can navigate the hierarchy (e.g., ‘IDLWAVE Code Formatting->Idlwave Abbrev And Indent Action->Idlwave Expand Generic End’ to turn on END expansion), read about the variables, change them, and “Save for Future Sessions”. Few of these variables need customization, but you can exercise considerable control over IDLWAVE’s functionality with them.

You may also find the key bindings used for the debugging commands too long and complicated. Often we have heard complaints along the lines of, “Do I really have to go through the finger gymnastics of C-c C-d C-c to run a simple command?” Due to Emacs rules and conventions, shorter bindings cannot be set by default, but you can easily enable them. First, there is a way to assign all debugging commands in a single sweep to another simpler combination. The only problem is that we have to use something which Emacs does not need for other important commands. One good option is to execute debugging commands by holding down CONTROL and SHIFT while pressing a single character: C-S-b for setting a breakpoint, C-S-c for compiling the current source file, C-S-a for deleting all breakpoints (try it, it’s easier). You can enable this with:

(setq idlwave-shell-debug-modifiers '(shift control))

If you have a special keyboard with, for example, a SUPER key, you could even shorten that:

(setq idlwave-shell-debug-modifiers '(super))

to get compilation on S-c. Often, a modifier key like SUPER or HYPER is bound or can be bound to an otherwise unused key on your keyboard; consult your system documentation.

You can also assign specific commands to keys. This you must do in the mode-hook, a special function which is run when a new IDLWAVE buffer gets set up. The possibilities for key customization are endless. Here we set function keys f4-f8 to common debugging commands.

;; First for the source buffer
(add-hook 'idlwave-mode-hook
   (lambda ()
    (local-set-key [f4] 'idlwave-shell-retall)
    (local-set-key [f5] 'idlwave-shell-break-here)
    (local-set-key [f6] 'idlwave-shell-clear-current-bp)
    (local-set-key [f7] 'idlwave-shell-cont)
    (local-set-key [f8] 'idlwave-shell-clear-all-bp)))
;; Then for the shell buffer
(add-hook 'idlwave-shell-mode-hook
   (lambda ()
    (local-set-key [f4] 'idlwave-shell-retall)
    (local-set-key [f5] 'idlwave-shell-break-here)
    (local-set-key [f6] 'idlwave-shell-clear-current-bp)
    (local-set-key [f7] 'idlwave-shell-cont)
    (local-set-key [f8] 'idlwave-shell-clear-all-bp)))

3.3 Lesson III: User and Library Catalogs

We have already used the routine info display in the first part of this tutorial. This was the invoked using C-c ?, and displays information about the IDL routine near the cursor position. Wouldn’t it be nice to have the same kind of information available for your own routines and for the huge amount of code in major libraries like JHUAPL or the IDL-Astro library? In many cases, you may already have this information. Files named .idlwave_catalog in library directories contain scanned information on the routines in that directory; many popular libraries ship with these “library catalogs” pre-scanned. Users can scan their own routines in one of two ways: either using the supplied tool to scan directories and build their own .idlwave_catalog files, or using the built-in method to create a single “user catalog”, which we’ll show here. See Catalogs, for more information on choosing which method to use.

To build a user catalog, select Routine Info/Select Catalog Directories from the IDLWAVE entry in the menu bar. If necessary, start the shell first with C-c C-s (see Starting the Shell). IDLWAVE will find out about the IDL !PATH variable and offer a list of directories on the path. Simply select them all (or whichever you want; directories with existing library catalogs will not be selected by default) and click on the ‘Scan&Save’ button. Then go for a cup of coffee while IDLWAVE collects information for each and every IDL routine on your search path. All this information is written to the file ~/.emacs.d/idlwave/idlusercat.el and will from now on automatically load whenever you use IDLWAVE. You may find it necessary to rebuild the catalog on occasion as your local libraries change, or build a library catalog for those directories instead. Invoke routine info (C-c ?) or completion (M-TAB) on any routine or partial routine name you know to be located in the library. E.g., if you have scanned the IDL-Astro library:


expands to “readfits(”. Then try

    a=readfits(C-c ?

and you get:

Usage:    Result = READFITS(filename, header, heap)

I hope you made it until here. Now you are set to work with IDLWAVE. On the way you will want to change other things, and to learn more about the possibilities not discussed in this short tutorial. Read the manual, look at the documentation strings of interesting variables (with C-h v idlwave<-variable-name> RET) and ask the remaining questions on the newsgroup comp.lang.idl-pvwave.

4 The IDLWAVE Major Mode

The IDLWAVE major mode supports editing IDL source files. In this chapter we describe the main features of the mode and how to customize them.

4.1 Code Formatting

The IDL language, with its early roots in FORTRAN, modern implementation in C, and liberal borrowing of features of many vector and other languages along its 30+ year history, has inherited an unusual mix of syntax elements. Left to his or her own devices, a novice IDL programmer will often conjure code which is very difficult to read and impossible to adapt. Much can be gleaned from studying available IDL code libraries for coding style pointers, but, due to the variety of IDL syntax elements, replicating this style can be challenging at best. Luckily, IDLWAVE understands the structure of IDL code very well, and takes care of almost all formatting issues for you. After configuring it to match your coding standards, you can rely on it to help keep your code neat and organized.

4.1.1 Code Indentation

Like all Emacs programming modes, IDLWAVE performs code indentation. The TAB key indents the current line relative to context. LFD insert a newline and indents the new line. The indentation is governed by a number of variables. IDLWAVE indents blocks (between PRO/FUNCTION/BEGIN and END), and continuation lines.

To re-indent a larger portion of code (e.g., when working with foreign code written with different conventions), use C-M-\ (indent-region) after marking the relevant code. Useful marking commands are C-x h (the entire file) or C-M-h (the current subprogram). The command C-M-q reindents the entire current routine. See Actions, for information how to impose additional formatting conventions on foreign code.

User Option: idlwave-main-block-indent (2)

Extra indentation for the main block of code. That is the block between the FUNCTION/PRO statement and the END statement for that program unit.

User Option: idlwave-block-indent (3)

Extra indentation applied to block lines. If you change this, you probably also want to change idlwave-end-offset.

User Option: idlwave-end-offset (-3)

Extra indentation applied to block END lines. A value equal to negative idlwave-block-indent will make END lines line up with the block BEGIN lines.

4.1.2 Continued Statement Indentation

Continuation lines (following a line ending with $) can receive a fixed indentation offset from the main level, but in several situations IDLWAVE can use a special form of indentation which aligns continued statements more naturally. Special indentation is calculated for continued routine definition statements and calls, enclosing parentheses (like function calls, structure/class definitions, explicit structures or lists, etc.), and continued assignments. An attempt is made to line up with the first non-whitespace character after the relevant opening punctuation mark (,,(,{,[,=). For lines without any non-comment characters on the line with the opening punctuation, the continued line(s) are aligned just past the punctuation. An example:

function foo, a, b,  $
              c, d
  bar =  sin( a + b + $
              c + d)

The only drawback to this special continued statement indentation is that it consumes more space, e.g., for long function names or left hand sides of an assignment:

function thisfunctionnameisverylongsoitwillleavelittleroom, a, b, $
                                                            c, d

You can instruct IDLWAVE when to avoid using this special continuation indentation by setting the variable idlwave-max-extra-continuation-indent, which specifies the maximum additional indentation beyond the basic indent to be tolerated, otherwise defaulting to a fixed-offset from the enclosing indent (the size of which offset is set in idlwave-continuation-indent). As a special case, continuations of routine calls without any arguments or keywords will not align the continued line, under the assumption that you continued because you needed the space.

Also, since the indentation level can be somewhat dynamic in continued statements with special continuation indentation, especially if idlwave-max-extra-continuation-indent is small, the key C-u TAB will re-indent all lines in the current statement. Note that idlwave-indent-to-open-paren, if non-nil, overrides the idlwave-max-extra-continuation-indent limit, for parentheses only, forcing them always to line up.

User Option: idlwave-continuation-indent (2)

Extra indentation applied to normal continuation lines.

User Option: idlwave-max-extra-continuation-indent (20)

The maximum additional indentation (over the basic continuation-indent) that will be permitted for special continues. To effectively disable special continuation indentation, set to 0. To enable it constantly, set to a large number (like 100). Note that the indentation in a long continued statement never decreases from line to line, outside of nested parentheses statements.

User Option: idlwave-indent-to-open-paren (t)

Non-nil means indent continuation lines to innermost open parenthesis, regardless of whether the idlwave-max-extra-continuation-indent limit is satisfied.

4.1.3 Comment Indentation

In IDL, lines starting with a ‘;’ are called comment lines. Comment lines are indented as follows:

;;;The indentation of lines starting with three semicolons remains unchanged.
;;Lines starting with two semicolons are indented like the surrounding code.
;Lines starting with a single semicolon are indented to a minimum column.

The indentation of comments starting in column 0 is never changed.

User Option: idlwave-no-change-comment

The indentation of a comment starting with this regexp will not be changed.

User Option: idlwave-begin-line-comment

A comment anchored at the beginning of line.

User Option: idlwave-code-comment

A comment that starts with this regexp is indented as if it is a part of IDL code.

4.1.4 Continuation Lines and Filling

In IDL, a newline character terminates a statement unless preceded by a ‘$’. If you would like to start a continuation line, use M-RET, which calls the command idlwave-split-line. It inserts the continuation character ‘$’, terminates the line and indents the new line. The command M-RET can also be invoked inside a string to split it at that point, in which case the ‘+’ concatenation operator is used.

When filling comment paragraphs, IDLWAVE overloads the normal filling functions and uses a function which creates the hanging paragraphs customary in IDL routine headers. When auto-fill-mode is turned on (toggle with C-c C-a), comments will be auto-filled. If the first line of a paragraph contains a match for idlwave-hang-indent-regexp (a dash-space by default), subsequent lines are positioned to line up after it, as in the following example.

; x - an array containing
;     lots of interesting numbers.
; y - another variable where
;     a hanging paragraph is used
;     to describe it.

You can also refill a comment at any time paragraph with M-q. Comment delimiting lines as in the above example, consisting of one or more ‘;’ followed by one or more of the characters ‘+=-_*’, are kept in place, as is.

User Option: idlwave-fill-comment-line-only (t)

Non-nil means auto fill will only operate on comment lines.

User Option: idlwave-auto-fill-split-string (t)

Non-nil means auto fill will split strings with the IDL ‘+’ operator.

User Option: idlwave-split-line-string (t)

Non-nil means idlwave-split-line will split strings with ‘+’.

User Option: idlwave-hanging-indent (t)

Non-nil means comment paragraphs are indented under the hanging indent given by idlwave-hang-indent-regexp match in the first line of the paragraph.

User Option: idlwave-hang-indent-regexp ("- ")

Regular expression matching the position of the hanging indent in the first line of a comment paragraph.

User Option: idlwave-use-last-hang-indent (nil)

Non-nil means use last match on line for idlwave-indent-regexp.

4.1.5 Syntax Highlighting

Highlighting of keywords, comments, strings etc. can be accomplished with font-lock. If you are using global-font-lock-mode, or have font-lock-mode turned on in any other buffer, it should also automatically work in IDLWAVE buffers. If you’d prefer invoking font-lock individually by mode, you can enforce it in idlwave-mode with the following line in your .emacs:

(add-hook 'idlwave-mode-hook 'turn-on-font-lock)

IDLWAVE supports 3 increasing levels of syntax highlighting. The variable font-lock-maximum-decoration determines which level is selected. Individual categories of special tokens can be selected for highlighting using the variable idlwave-default-font-lock-items.

User Option: idlwave-default-font-lock-items

Items which should be fontified on the default fontification level 2.

4.1.6 Octals and Highlighting

A rare syntax highlighting problem results from an extremely unfortunate notation for octal numbers in IDL: "123. This unpaired quotation mark is very difficult to parse, given that it can be mixed on a single line with any number of strings. Emacs will incorrectly identify this as a string, and the highlighting of following lines of code can be distorted, since the string is never terminated.

One solution to this involves terminating the mistakenly identified string yourself by providing a closing quotation mark in a comment:

  string("305B) + $ ;" <--- for font-lock
   ' is an Angstrom.'

A far better solution is to abandon this notation for octals altogether, and use the more sensible alternative IDL provides:

   string('305'OB) + ' is an Angstrom.'

This simultaneously solves the font-lock problem and is more consistent with the notation for hexadecimal numbers, e.g., 'C5'XB.

4.2 Routine Info

IDL comes bundled with more than one thousand procedures, functions and object methods, and large libraries typically contain hundreds or even thousands more (each with a few to tens of keywords and arguments). This large command set can make it difficult to remember the calling sequence and keywords for the routines you use, but IDLWAVE can help. It builds up routine information from a wide variety of sources; IDLWAVE in fact knows far more about the ‘.pro’ routines on your system than IDL itself! It maintains a list of all built-in routines, with calling sequences and keywords3. It also scans Emacs buffers for routine definitions, queries the IDLWAVE-Shell for information about routines currently compiled there, and automatically locates library and user-created catalogs. This information is updated automatically, and so should usually be current. To force a global update and refresh the routine information, use C-c C-i (idlwave-update-routine-info).

To display the information about a routine, press C-c ?, which calls the command idlwave-routine-info. When the current cursor position is on the name or in the argument list of a procedure or function, information will be displayed about the routine. For example, consider the indicated cursor positions in the following line:

plot,x,alog(x+5*sin(x) + 2),
  |  |   |   |   |  |  |    |
  1  2   3   4   5  6  7    8

On positions 1,2 and 8, information about the ‘plot’ procedure will be shown. On positions 3,4, and 7, the ‘alog’ function will be described, while positions 5 and 6 will investigate the ‘sin’ function.

When you ask for routine information about an object method, and the method exists in several classes, IDLWAVE queries for the class of the object, unless the class is already known through a text property on the ‘->’ operator (see Object Method Completion and Class Ambiguity), or by having been explicitly included in the call (e.g., a->myclass::Foo).

The description displayed contains the calling sequence, the list of keywords and the source location of this routine. It looks like this:

Source:   SystemLib   [LCSB] /soft1/idl53/lib/

If a definition of this routine exists in several files accessible to IDLWAVE, several ‘Source’ lines will point to the different files. This may indicate that your routine is shadowing a system library routine, which may or may not be what you want (see Load-Path Shadows). The information about the calling sequence and keywords is derived from the first source listed. Library routines are available only if you have scanned your local IDL directories or are using pre-scanned libraries (see Catalogs). The source entry consists of a source category, a set of flags and the path to the source file. The following default categories exist:

SystemA system routine of unknown origin. When the system library has been scanned as part of a catalog (see Catalogs), this category will automatically split into the next two.
BuiltinA builtin system routine with no source code available.
SystemLibA library system routine in the official lib directory !DIR/lib.
ObsoleteA library routine in the official lib directory !DIR/lib/obsolete.
LibraryA routine in a file on IDL’s search path !PATH.
OtherAny other routine with a file not known to be on the search path.
UnresolvedAn otherwise unknown routine the shell lists as unresolved (referenced, but not compiled).

Any routines discovered in library catalogs (see Library Catalogs), will display the category assigned during creation, e.g., ‘NasaLib’. For routines not discovered in this way, you can create additional categories based on the routine’s filename using the variable idlwave-special-lib-alist.

The flags [LCSB] indicate the source of the information IDLWAVE has regarding the file: from a library catalog ([L---]), from a user catalog ([-C--], from the IDL Shell ([--S-]) or from an Emacs buffer ([---B]). Combinations are possible (a compiled library routine visited in a buffer might read [L-SB]). If a file contains multiple definitions of the same routine, the file name will be prefixed with ‘(Nx)’ where ‘N’ is the number of definitions.

Some of the text in the *Help* routine info buffer will be active (it is highlighted when the mouse moves over it). Typically, clicking with the right mouse button invokes online help lookup, and clicking with the middle mouse button inserts keywords or visits files:

UsageIf online help is installed, a click with the right mouse button on the Usage: line will access the help for the routine (see Online Help).
KeywordOnline help about keywords is also available with the right mouse button. Clicking on a keyword with the middle mouse button will insert this keyword in the buffer from where idlwave-routine-info was called. Holding down SHIFT while clicking also adds the initial ‘/’.
SourceClicking with the middle mouse button on a ‘Source’ line finds the source file of the routine and visits it in another window. Another click on the same line switches back to the buffer from which C-c ? was called. If you use the right mouse button, the source will not be visited by a buffer, but displayed in the online help window.
ClassesThe Classes line is only included in the routine info window if the current class inherits from other classes. You can click with the middle mouse button to display routine info about the current method in other classes on the inheritance chain, if such a method exists there.
User Option: idlwave-resize-routine-help-window (t)

Non-nil means resize the Routine-info *Help* window to fit the content.

User Option: idlwave-special-lib-alist

Alist of regular expressions matching special library directories.

User Option: idlwave-rinfo-max-source-lines (5)

Maximum number of source files displayed in the Routine Info window.

4.3 Online Help

For IDL system routines, extensive documentation is supplied with IDL. IDLWAVE can access the HTML version of this documentation very quickly and accurately, based on the local context. This can be faster than using the IDL online help application, because IDLWAVE usually gets you to the right place in the documentation directly — e.g., a specific keyword of a routine — without any additional browsing and scrolling.

For this online help to work, an HTML version of the IDL documentation is required. Beginning with IDL 6.2, HTML documentation is distributed directly with IDL, along with an XML-based catalog of routine information. By default, IDLWAVE automatically attempts to convert this XML catalog into a format Emacs can more easily understand, and caches this information in your idlwave_config_directory (~/.emacs.d/idlwave/, by default). It also re-scans the XML catalog if it is newer than the current cached version. You can force rescan with the menu entry IDLWAVE->Routine Info->Rescan XML Help Catalog.

Before IDL 6.2, the HTML help was not distributed with IDL, and was not part of the standalone IDLWAVE distribution, but had to be downloaded separately. This is no longer necessary: all help and routine information is supplied with IDL versions 6.2 and later.

Starting with IDL 7.0, the HTML help system and associated IDL Assistant tool was dropped for an Eclipse-based help system, without access to the documentation mediated via the ‘idlhelp’ tool. In IDL 7.1, this access was restored.

There are a variety of options for displaying the HTML help: see below. Help for routines without HTML documentation is also available, by using the routine documentation header and/or routine source.

In any IDL program (or, as with most IDLWAVE commands, in the IDL Shell), press M-? (idlwave-context-help), or click with S-mouse-3 to access context sensitive online help. The following locations are recognized context for help:

Routine namesThe name of a routine (function, procedure, method).
Keyword ParametersA keyword parameter of a routine.
System VariablesSystem variables like !DPI.
System Variable TagsSystem variables tags like !D.X_SIZE.
IDL StatementsStatements like PRO, REPEAT, COMPILE_OPT, etc.
IDL ControlsControl structures like FOR, SWITCH, etc.
Class namesA class name in an OBJ_NEW call.
Class Init KeywordsBeyond the class name in an OBJ_NEW call.
Executive CommandAn executive command like .RUN. Mostly useful in the shell.
Structure TagsStructure tags like state.xsize
Class TagsClass tags like self.value.
DefaultThe routine that would be selected for routine info display.

Note that the OBJ_NEW function is special in that the help displayed depends on the cursor position. If the cursor is on the ‘OBJ_NEW’, this function is described. If it is on the class name inside the quotes, the documentation for the class is pulled up. If the cursor is after the class name, anywhere in the argument list, the documentation for the corresponding Init method and its keywords is targeted.

Apart from an IDLWAVE buffer or shell, there are two more places from which online help can be accessed.

  • Online help for routines and keywords can be accessed through the Routine Info display. Click with mouse-3 on an item to see the corresponding help (see Routine Info).
  • When using completion and Emacs pops up a *Completions* buffer with possible completions, clicking with mouse-3 on a completion item invokes help on that item (see Completion). Items for which help is available in the online system documentation (vs. just the program source itself) will be emphasized (e.g., colored blue).

In both cases, a blue face indicates that the item is documented in the IDL manual, but an attempt will be made to visit non-blue items directly in the originating source file.

4.3.1 Help with HTML Documentation

This section is relevant only to version of IDL <7.0, at which point the HTML help system was replaced with the Eclipse-based help system. It is not longer possible to browse the HTML help using alternative browsers (c.f. the ‘idlhelp’ tool). IDLWAVE automatically detects which help system you have, and uses it.

Help using the HTML documentation is invoked with the built-in Emacs command browse-url, which displays the relevant help topic in a browser of your choosing. Beginning with version 6.2, IDL comes with the help browser IDL Assistant, which it uses by default for displaying online help on all supported platforms. This browser offers topical searches, an index, and is also now the default and recommended IDLWAVE help browser. The variable idlwave-help-use-assistant controls whether this browser is used. Note that, due to limitations in the Assistant, invoking help within IDLWAVE and ? topic within IDL will result in two running copies of Assistant.

Aside from the IDL Assistant, there are many possible browsers to choose among, with differing advantages and disadvantages. The variable idlwave-help-browser-function controls which browser help is sent to (as long as idlwave-help-use-assistant is not set). This function is used to set the variable browse-url-browser-function locally for IDLWAVE help only. Customize the latter variable to see what choices of browsers your system offers. Certain browsers like EWW (see EWW in The Emacs Web Wowser Manual) are run within Emacs, and use Emacs buffers to display the HTML help. This can be convenient, especially on small displays, and images can even be displayed in-line on newer Emacs versions. However, better formatting results are often achieved with external browsers, like Mozilla. IDLWAVE assumes any browser function containing "w3" is displayed in a local buffer. If you are using another Emacs-local browser for which this is not true, set the variable idlwave-help-browser-is-local.

With IDL 6.2 or later, it is important to ensure that the variable idlwave-system-directory is set (see Catalogs). One easy way to ensure this is to run the IDL Shell (C-c C-s). It will be queried for this directory, and the results will be cached to file for subsequent use.

See HTML Help Browser Tips, for more information on selecting and configuring a browser for use with IDL’s HTML help system.

User Option: idlwave-html-system-help-location help/online_help

Relative directory of the system-supplied HTML help directory, considered with respect to idlwave-system-directory. Relevant for IDL 6.2 and greater. Should not change.

User Option: idlwave-html-help-location /usr/local/etc/

The directory where the idl_html_help HTML directory live. Obsolete and ignored for IDL 6.2 and greater (idlwave-html-system-help-location is used instead).

User Option: idlwave-help-use-assistant t

If set, use the IDL Assistant if possible for online HTML help, otherwise use the browser function specified in idlwave-help-browser-function.

User Option: idlwave-help-browser-function

The browser function to use to display IDLWAVE HTML help. Should be one of the functions available for setting browse-url-browser-function, which see.

User Option: idlwave-help-browser-is-local

Is the browser selected in idlwave-help-browser-function run in a local Emacs buffer or window? Defaults to t if the function contains "-w3".

The face for links to IDLWAVE online help.

4.3.2 Help with Source

For routines which are not documented in an HTML manual (for example personal or library routines), the source code itself is used as help text. If the requested information can be found in a (more or less) standard DocLib file header, IDLWAVE shows the header (scrolling down to a keyword, if appropriate). Otherwise the routine definition statement (pro/function) is shown. The doclib header sections which are searched for include ‘NAME’ and ‘KEYWORDS’. Localization support can be added by customizing the idlwave-help-doclib-name and idlwave-help-doclib-keyword variables.

Help is also available for class structure tags (self.TAG), and generic structure tags, if structure tag completion is enabled (see Structure Tag Completion). This is implemented by visiting the tag within the class or structure definition source itself. Help is not available on built-in system class tags.

The help window is normally displayed in the same frame, but can be popped-up in a separate frame. The following commands can be used to navigate inside the help system for source files:

SPACEScroll forward one page.
RETScroll forward one line.
DELScroll back one page.
hJump to DocLib Header of the routine whose source is displayed as help.
HJump to the first DocLib Header in the file.
. (Dot)Jump back and forth between the routine definition (the pro/function statement) and the description of the help item in the DocLib header.
FFontify the buffer like source code. See the variable idlwave-help-fontify-source-code.
qKill the help window.
User Option: idlwave-help-use-dedicated-frame (nil)

Non-nil means use a separate frame for Online Help if possible.

User Option: idlwave-help-frame-parameters

The frame parameters for the special Online Help frame.

User Option: idlwave-max-popup-menu-items (20)

Maximum number of items per pane in pop-up menus.

User Option: idlwave-extra-help-function

Function to call for help if the normal help fails.

User Option: idlwave-help-fontify-source-code (nil)

Non-nil means fontify source code displayed as help.

User Option: idlwave-help-source-try-header (t)

Non-nil means try to find help in routine header when displaying source file.

User Option: idlwave-help-doclib-name ("name")

The case-insensitive heading word in doclib headers to locate the name section. Can be a regexp, e.g., "\\(name\\|nom\\)".

User Option: idlwave-help-doclib-keyword ("KEYWORD")

The case-insensitive heading word in doclib headers to locate the keywords section. Can be a regexp.

4.4 Completion

IDLWAVE offers completion for class names, routine names, keywords, system variables, system variable tags, class structure tags, regular structure tags and file names. As in many programming modes, completion is bound to M-TAB (or simply TAB in the IDLWAVE Shell; see Using the Shell). Completion uses exactly the same internal information as routine info, so when necessary (rarely) it can be updated with C-c C-i (idlwave-update-routine-info).

The completion function is context sensitive and figures out what to complete based on the location of the point. Here are example lines and what M-TAB would try to complete when the cursor is on the position marked with a ‘_’:

plo_                    Procedure
x = a_                  Function
plot,xra_               Keyword of plot procedure
plot,x,y,/x_            Keyword of plot procedure
plot,min(_              Keyword of min function
obj -> a_               Object method (procedure)
a[2,3] = obj -> a_      Object method (function)
x = obj_new('IDL_       Class name
x = obj_new('MyCl',a_   Keyword to Init method in class MyCl
pro A_                  Class name
pro _                   Fill in Class:: of first method in this file
!v_                     System variable
!version.t_             Structure tag of system variable
self.g_                 Class structure tag in methods
state.w_                Structure tag, if tag completion enabled
name = 'a_              File name (default inside quotes)

The only place where completion is ambiguous is procedure/function keywords versus functions. After ‘plot,x,_’, IDLWAVE will always assume a keyword to ‘plot’. However, a function is also a possible completion here. You can force completion of a function name at such a location by using a prefix arg: C-u M-TAB.

Giving two prefix arguments (C-u C-u M-TAB) prompts for a regular expression to search among the commands to be completed. As an example, completing a blank line in this way will allow you to search for a procedure matching a regexp.

If the list of completions is too long to fit in the *Completions* window, the window can be scrolled by pressing M-TAB repeatedly. Online help (if installed) for each possible completion is available by clicking with mouse-3 on the item. Items for which system online help (from the IDL manual) is available will be emphasized (e.g., colored blue). For other items, the corresponding source code or DocLib header will be used as the help text.

Completion is not a blocking operation; you are free to continue editing, enter commands, or simply ignore the *Completions* buffer during a completion operation. If, however, the most recent command was a completion, C-g will remove the buffer and restore the window configuration. You can also remove the buffer at any time with no negative consequences.

User Option: idlwave-keyword-completion-adds-equal (t)

Non-nil means completion automatically adds ‘=’ after completed keywords.

User Option: idlwave-function-completion-adds-paren (t)

Non-nil means completion automatically adds ‘(’ after completed function. A value of 2 means also add the closing parenthesis and position the cursor between the two.

User Option: idlwave-completion-restore-window-configuration (t)

Non-nil means restore window configuration after successful completion.

Non-nil means highlight completions for which system help is available.

4.4.1 Case of Completed Words

IDL is a case-insensitive language, so casing is a matter of style only. IDLWAVE helps maintain a consistent casing style for completed items. The case of the completed words is determined by what is already in the buffer. As an exception, when the partial word being completed is all lower case, the completion will be lower case as well. If at least one character is upper case, the string will be completed in upper case or mixed case, depending on the value of the variable idlwave-completion-case. The default is to use upper case for procedures, functions and keywords, and mixed case for object class names and methods, similar to the conventions in the IDL manuals. For instance, to enable mixed-case completion for routines in addition to classes and methods, you need an entry such as (routine . preserve) in that variable. To enable total control over the case of completed items, independent of buffer context, set idlwave-completion-force-default-case to non-nil.

User Option: idlwave-completion-case

Association list setting the case (UPPER/lower/Capitalized/MixedCase...) of completed words.

User Option: idlwave-completion-force-default-case (nil)

Non-nil means completion will always honor the settings in idlwave-completion-case. When nil (the default), entirely lower case strings will always be completed to lower case, no matter what the settings in idlwave-completion-case.

User Option: idlwave-complete-empty-string-as-lower-case (nil)

Non-nil means the empty string is considered lower case for completion.

4.4.2 Object Method Completion and Class Ambiguity

An object method is not uniquely determined without the object’s class. Since the class is almost always omitted in the calling source (as required to obtain the true benefits of object-based programming), IDLWAVE considers all available methods in all classes as possible method name completions. The combined list of keywords of the current method in all known classes which contain that method will be considered for keyword completion. In the *Completions* buffer, the matching classes will be shown next to each item (see option idlwave-completion-show-classes). As a special case, the class of an object called ‘self’ is always taken to be the class of the current routine, when in an IDLWAVE buffer. All inherits classes are considered as well.

You can also call idlwave-complete with a prefix arg: C-u M-TAB. IDLWAVE will then prompt you for the class in order to narrow down the number of possible completions. The variable idlwave-query-class can be configured to make such prompting the default for all methods (not recommended), or selectively for very common methods for which the number of completing keywords would be too large (e.g., Init,SetProperty,GetProperty).

After you have specified the class for a particular statement (e.g., when completing the method), IDLWAVE can remember it for the rest of the editing session. Subsequent completions in the same statement (e.g., keywords) can then reuse this class information. This works by placing a text property on the method invocation operator ‘->’, after which the operator will be shown in a different face (bold by default). The variable idlwave-store-inquired-class can be used to turn it off or on.

User Option: idlwave-completion-show-classes (1)

Non-nil means show up to that many classes in *Completions* buffer when completing object methods and keywords.

User Option: idlwave-completion-fontify-classes (t)

Non-nil means fontify the classes in completions buffer.

User Option: idlwave-query-class (nil)

Association list governing query for object classes during completion.

User Option: idlwave-store-inquired-class (t)

Non-nil means store class of a method call as text property on ‘->’.

User Option: idlwave-class-arrow-face

Face to highlight object operator arrows ‘->’ which carry a saved class text property.

4.4.3 Object Method Completion in the Shell

In the IDLWAVE Shell (see The IDLWAVE Shell), objects on which methods are being invoked have a special property: they must exist as variables, and so their class can be determined (for instance, using the obj_class() function). In the Shell, when attempting completion, routine info, or online help within a method routine, a query is sent to determine the class of the object. If this query is successful, the class found will be used to select appropriate completions, routine info, or help. If unsuccessful, information from all known classes will be used (as in the buffer).

4.4.4 Class and Keyword Inheritance

Class inheritance affects which methods are called in IDL. An object of a class which inherits methods from one or more superclasses can override that method by defining its own method of the same name, extend the method by calling the method(s) of its superclass(es) in its version, or inherit the method directly by making no modifications. IDLWAVE examines class definitions during completion and routine information display, and records all inheritance information it finds. This information is displayed if appropriate with the calling sequence for methods (see Routine Info), as long as variable idlwave-support-inheritance is non-nil.

In many class methods, keyword inheritance (_EXTRA and _REF_EXTRA) is used hand-in-hand with class inheritance and method overriding. E.g., in a SetProperty method, this technique allows a single call obj->SetProperty to set properties up the entire class inheritance chain. This is often referred to as chaining, and is characterized by chained method calls like self->MySuperClass::SetProperty,_EXTRA=e.

IDLWAVE can accommodate this special synergy between class and keyword inheritance: if _EXTRA or _REF_EXTRA is detected among a method’s keyword parameters, all keywords of superclass versions of the method being considered can be included in completion. There is of course no guarantee that this type of keyword chaining actually occurs, but for some methods it’s a very convenient assumption. The variable idlwave-keyword-class-inheritance can be used to configure which methods have keyword inheritance treated in this simple, class-driven way. By default, only Init and (Get|Set)Property are. The completion buffer will label keywords based on their originating class.

User Option: idlwave-support-inheritance (t)

Non-nil means consider inheritance during completion, online help etc.

User Option: idlwave-keyword-class-inheritance

A list of regular expressions to match methods for which simple class-driven keyword inheritance will be used for Completion.

4.4.5 Structure Tag Completion

In many programs, especially those involving widgets, large structures (e.g., the ‘state’ structure) are used to communicate among routines. It is very convenient to be able to complete structure tags, in the same way as for instance variables (tags) of the ‘self’ object (see Object Method Completion and Class Ambiguity). Tag completion in structures is highly ambiguous (much more so than ‘self’ completion), so idlw-complete-structtag makes an unusual and very specific assumption: the exact same variable name is used to refer to the structure in all parts of the program. This is entirely unenforced by the IDL language, but is a typical convention. If you consistently refer to the same structure with the same variable name (e.g., ‘state’), structure tags which are read from its definition in the same file can be used for completion.

Structure tag completion is enabled by default. You’ll also be able to access online help on the structure tags, using the usual methods (see Online Help). In addition, structure variables in the shell will be queried for tag names, similar to the way object variables in the shell are queried for method names. So, e.g.:

IDL> st.[Tab]

will complete with all structure fields of the structure st.

User Option: idlwave-complete-structure-tags (t)

Non-nil means complete structure tags in the source buffers and shell.

4.5 Routine Source

In addition to clicking on a Source: line in the routine info window, there is another way to quickly visit the source file of a routine. The command C-c C-v (idlwave-find-module) asks for a module name, offering the same default as idlwave-routine-info would have used, taken from nearby buffer contents. In the minibuffer, specify a complete routine name (including any class part). IDLWAVE will display the source file in another window, positioned at the routine in question. You can also limit this to a routine in the current buffer only, with completion, and a context-sensitive default, by using a single prefix (C-u C-c C-v) or the convenience binding C-c C-t.

Since getting the source of a routine into a buffer is so easy with IDLWAVE, too many buffers visiting different IDL source files are sometimes created. The special command C-c C-k (idlwave-kill-autoloaded-buffers) can be used to easily remove these buffers.

4.6 Resolving Routines

The key sequence C-c = calls the command idlwave-resolve and sends the line ‘RESOLVE_ROUTINE, 'routine_name'’ to IDL in order to resolve (compile) it. The default routine to be resolved is taken from context, but you get a chance to edit it. Usually this is not necessary, since IDL automatically discovers routines on its path.

idlwave-resolve is one way to get a library module within reach of IDLWAVE’s routine info collecting functions. A better way is to keep routine information available in catalogs (see Catalogs). Routine info on modules will then be available without the need to compile the modules first, and even without a running shell.

See Sources of Routine Info, for more information on the ways IDLWAVE collects data about routines, and how to update this information.

4.7 Code Templates

IDLWAVE can insert IDL code templates into the buffer. For a few templates, this is done with direct key bindings:

C-c C-cCASE statement template
C-c C-fFOR loop template
C-c C-rREPEAT loop template
C-c C-wWHILE loop template

All code templates are also available as abbreviations (see Abbreviations).

4.8 Abbreviations

Special abbreviations exist to enable rapid entry of commonly used commands. Emacs abbreviations are expanded by typing text into the buffer and pressing SPC or RET. The special abbreviations used to insert code templates all start with a ‘\’ (the backslash), or, optionally, any other character set in idlwave-abbrev-start-char. IDLWAVE ensures that abbreviations are only expanded where they should be (i.e., not in a string or comment), and permits the point to be moved after an abbreviation expansion: very useful for positioning the mark inside of parentheses, etc.

Special abbreviations are pre-defined for code templates and other useful items. To visit the full list of abbreviations, use M-x idlwave-list-abbrevs.

Template abbreviations:

\prPROCEDURE template
\fuFUNCTION template
\cCASE statement template
\fFOR loop template
\rREPEAT loop template
\wWHILE loop template
\iIF statement template
\elifIF-ELSE statement template

String abbreviations:

\eiendif else if
\elendif else
\ikif keyword_set() then
\iapif arg_present() then
\ineif n_elements() eq 0 then
\innif n_elements() ne 0 then

You can easily add your own abbreviations or override existing abbrevs with define-abbrev in your mode hook, using the convenience function idlwave-define-abbrev:

(add-hook 'idlwave-mode-hook
          (lambda ()
            (idlwave-define-abbrev "wb" "widget_base()"
                     (idlwave-keyword-abbrev 1))
            (idlwave-define-abbrev "ine" "IF N_Elements() EQ 0 THEN"
                     (idlwave-keyword-abbrev 11))))

Notice how the abbreviation (here wb) and its expansion (widget_base()) are given as arguments, and the single argument to idlwave-keyword-abbrev (here 1) specifies how far back to move the point upon expansion (in this example, to put it between the parentheses).

The abbreviations are expanded in upper or lower case, depending upon the variables idlwave-abbrev-change-case and, for reserved word templates, idlwave-reserved-word-upcase (see Case Changes).

User Option: idlwave-abbrev-start-char ("\")

A single character string used to start abbreviations in abbrev mode. Beware of common characters which might naturally occur in sequence with abbreviation strings.

User Option: idlwave-abbrev-move (t)

Non-nil means the abbrev hook can move point, e.g., to end up between the parentheses of a function call.

4.9 Actions

Actions are special formatting commands which are executed automatically while you write code in order to check the structure of the program or to enforce coding standards. Most actions which have been implemented in IDLWAVE are turned off by default, assuming that the average user wants her code the way she writes it. But if you are a lazy typist and want your code to adhere to certain standards, actions can be helpful.

Actions can be applied in three ways:

  • Some actions are applied directly while typing. For example, pressing ‘=’ can run a check to make sure that this operator is surrounded by spaces and insert these spaces if necessary. Pressing SPC after a reserved word can call a command to change the word to upper case.
  • When a line is re-indented with TAB, actions can be applied to the entire line. To enable this, the variable idlwave-do-actions must be non-nil.
  • Actions can also be applied to a larger piece of code, e.g., to convert foreign code to your own style. To do this, mark the relevant part of the code and execute M-x expand-region-abbrevs. Useful marking commands are C-x h (the entire file) or C-M-h (the current subprogram). See Code Indentation, for information how to adjust the indentation of the code.
User Option: idlwave-do-actions (nil)

Non-nil means performs actions when indenting. Individual action settings are described below and set separately.

4.9.1 Block Boundary Check

Whenever you type an END statement, IDLWAVE finds the corresponding start of the block and the cursor blinks back to that location for a second. If you have typed a specific END, like ENDIF or ENDCASE, you get a warning if that terminator does not match the type of block it terminates.

Set the variable idlwave-expand-generic-end in order to have all generic END statements automatically expanded to the appropriate type. You can also type C-c ] to close the current block by inserting the appropriate END statement.

User Option: idlwave-show-block (t)

Non-nil means point blinks to block beginning for idlwave-show-begin.

User Option: idlwave-expand-generic-end (t)

Non-nil means expand generic END to ENDIF/ENDELSE/ENDWHILE etc.

User Option: idlwave-reindent-end (t)

Non-nil means re-indent line after END was typed.

4.9.2 Padding Operators

Some operators can be automatically surrounded by spaces. This can happen when the operator is typed, or later when the line is indented. IDLWAVE can pad the operators ‘<’, ‘>’, ‘,’, ‘=’, and ‘->’, as well as the modified assignment operators (‘AND=’, ‘OR=’, etc.). This feature is turned off by default. If you want to turn it on, customize the variables idlwave-surround-by-blank and idlwave-do-actions and turn both on. You can also define similar actions for other operators by using the function idlwave-action-and-binding in the mode hook. For example, to enforce space padding of the ‘+’ and ‘*’ operators (outside of strings and comments, of course), try this in .emacs

(add-hook 'idlwave-mode-hook
  (lambda ()
     (setq idlwave-surround-by-blank t)  ; Turn this type of actions on
     (idlwave-action-and-binding "*" '(idlwave-surround 1 1))
     (idlwave-action-and-binding "+" '(idlwave-surround 1 1))))

Note that the modified assignment operators which begin with a word (‘AND=’, ‘OR=’, ‘NOT=’, etc.) require a leading space to be recognized (e.g., vAND=4 would be interpreted as a variable vAND). Also note that since, e.g., > and >= are both valid operators, it is impossible to surround both by blanks while they are being typed. Similarly with & and &&. For these, a compromise is made: the padding is placed on the left, and if the longer operator is keyed in, on the right as well (otherwise you must insert spaces to pad right yourself, or press simply press Tab to repad everything if idlwave-do-actions is on).

User Option: idlwave-surround-by-blank (nil)

Non-nil means enable idlwave-surround. If non-nil, ‘=’, ‘<’, ‘>’, ‘&’, ‘,’, ‘->’, and the modified assignment operators (‘AND=’, ‘OR=’, etc.) are surrounded with spaces by idlwave-surround.

User Option: idlwave-pad-keyword (t)

Non-nil means space-pad the ‘=’ in keyword assignments.

Previous: , Up: Actions   [Contents][Index]

4.9.3 Case Changes

Actions can be used to change the case of reserved words or expanded abbreviations by customizing the variables idlwave-abbrev-change-case and idlwave-reserved-word-upcase. If you want to change the case of additional words automatically, put something like the following into your .emacs file:

(add-hook 'idlwave-mode-hook
  (lambda ()
     ;;  Capitalize system vars
     (idlwave-action-and-binding idlwave-sysvar '(capitalize-word 1) t)
     ;;  Capitalize procedure name
     (idlwave-action-and-binding "\\<\\(pro\\|function\\)\\>[ \t]*\\<"
                                 '(capitalize-word 1) t)
     ;;  Capitalize common block name
     (idlwave-action-and-binding "\\<common\\>[ \t]+\\<"
                                 '(capitalize-word 1) t)))

For more information, see the documentation string for the function idlwave-action-and-binding. For information on controlling the case of routines, keywords, classes, and methods as they are completed, see Completion.

User Option: idlwave-abbrev-change-case (nil)

Non-nil means all abbrevs will be forced to either upper or lower case. Valid values are nil, t, and down.

User Option: idlwave-reserved-word-upcase (nil)

Non-nil means reserved words will be made upper case via abbrev expansion.

4.10 Documentation Header

The command C-c C-h inserts a standard routine header into the buffer, with the usual fields for documentation (a different header can be specified with idlwave-file-header). One of the keywords is ‘MODIFICATION HISTORY’ under which the changes to a routine can be recorded. The command C-c C-m jumps to the ‘MODIFICATION HISTORY’ of the current routine or file and inserts the user name with a timestamp.

User Option: idlwave-file-header

The doc-header template or a path to a file containing it.

User Option: idlwave-header-to-beginning-of-file (nil)

Non-nil means the documentation header will always be at start of file.

User Option: idlwave-timestamp-hook

The hook function used to update the timestamp of a function.

User Option: idlwave-doc-modifications-keyword

The modifications keyword to use with the log documentation commands.

User Option: idlwave-doclib-start

Regexp matching the start of a document library header.

User Option: idlwave-doclib-end

Regexp matching the start of a document library header.

4.11 Motion Commands

IDLWAVE supports Imenu, a package which make it easy to jump to the definitions of functions and procedures in the current file with a pop-up selection. To bind Imenu to a mouse-press, use in your .emacs:

(define-key global-map [S-down-mouse-3] 'imenu)

In addition, Speedbar support allows convenient navigation of a source tree of IDL routine files, quickly stepping to routine definitions. See Tools->Display Speedbar.

Several commands allow you to move quickly through the structure of an IDL program:

C-M-aBeginning of subprogram
C-M-eEnd of subprogram
C-c {Beginning of block (stay inside the block)
C-c }End of block (stay inside the block)
C-M-nForward block (on same level)
C-M-pBackward block (on same level)
C-M-dDown block (enters a block)
C-M-uBackward up block (leaves a block)
C-c C-nNext Statement

4.12 Miscellaneous Options

User Option: idlwave-help-application

The external application providing reference help for programming.

User Option: idlwave-startup-message (t)

Non-nil means display a startup message when idlwave-mode’ is first called.

User Option: idlwave-mode-hook

Normal hook. Executed when a buffer is put into idlwave-mode.

5 The IDLWAVE Shell

The IDLWAVE shell is an Emacs major mode which permits running the IDL program as an inferior process of Emacs, and works closely with the IDLWAVE major mode in buffers. It can be used to work with IDL interactively, to compile and run IDL programs in Emacs buffers and to debug these programs. The IDLWAVE shell is built on comint, an Emacs packages which handles the communication with the IDL program. Unfortunately, IDL for Windows does not have command-prompt versions and thus do not allow the interaction with Emacs — so the IDLWAVE shell currently works only under UNIX and macOS.

5.1 Starting the Shell

The IDLWAVE shell can be started with the command M-x idlwave-shell. In idlwave-mode the function is bound to C-c C-s. It creates a buffer *idl* which is used to interact with the shell. If the shell is already running, C-c C-s will simply switch to the shell buffer. The command C-c C-l (idlwave-shell-recenter-shell-window) displays the shell window without selecting it. The shell can also be started automatically when another command tries to send a command to it. To enable auto start, set the variable idlwave-shell-automatic-start to t.

In order to create a separate frame for the IDLWAVE shell buffer, call idlwave-shell with a prefix argument: C-u C-c C-s or C-u C-c C-l. Two prefix argument (C-u C-u C-c C-s) will restore to the single frame mode. If you always want a dedicated frame for the shell window, configure the variable idlwave-shell-use-dedicated-frame. If you’d prefer the shell window to appear in the same frame, but at a reduced height, configure idlwave-shell-buffer-height-frac.

To launch a quick IDLWAVE shell directly from a shell prompt without an IDLWAVE buffer (e.g., as a replacement for running inside an xterm), define a system alias with the following content:

emacs -geometry 80x32 -eval "(idlwave-shell 'quick)"

Replace the ‘-geometry 80x32’ option with ‘-nw’ if you prefer the Emacs process to run directly inside the terminal window.

To use IDLWAVE with ENVI or other custom packages which change the ‘IDL> ’ prompt, you must change the idlwave-shell-prompt-pattern, which defaults to ‘"^ ?IDL> "’. Normally, you can just replace the ‘IDL’ in this expression with the prompt you see. A suitable pattern which matches the prompt for both ENVI and IDL simultaneously is ‘"^ ?\\(ENVI\\|IDL\\)> "’.

User Option: idlwave-shell-explicit-file-name (idl)

This is the command to run IDL.

User Option: idlwave-shell-command-line-options

A list of command line options for calling the IDL program.

User Option: idlwave-shell-prompt-pattern

Regexp to match IDL prompt at beginning of a line.

User Option: idlwave-shell-process-name

Name to be associated with the IDL process.

User Option: idlwave-shell-automatic-start (nil)

Non-nil means attempt to invoke idlwave-shell if not already running.

User Option: idlwave-shell-initial-commands

Initial commands, separated by newlines, to send to IDL.

User Option: idlwave-shell-save-command-history (t)

Non-nil means preserve command history between sessions.

User Option: idlwave-shell-command-history-file (~/.emacs.d/idlwave/.idlwhist)

The file in which the command history of the idlwave shell is saved. Unless it’s an absolute path, it goes in idlwave-config-directory.

User Option: idlwave-shell-use-dedicated-frame (nil)

Non-nil means IDLWAVE should use a special frame to display the shell buffer.

User Option: idlwave-shell-buffer-height-frac (nil)

Non-nil means make the shell buffer this fraction of the total frame height. E.g. 0.25 would mean the shell buffer occupies 1/4 of the total frame. Only relevant if idlwave-shell-use-dedicated-frame is nil.

User Option: idlwave-shell-use-dedicated-window (nil)

Non-nil means use a dedicated window for the shell, taking care not it replace it with other buffers.

User Option: idlwave-shell-frame-parameters

The frame parameters for a dedicated idlwave-shell frame.

User Option: idlwave-shell-raise-frame (t)

Non-nil means idlwave-shell raises the frame showing the shell window.

User Option: idlwave-shell-temp-pro-prefix

The prefix for temporary IDL files used when compiling regions.

User Option: idlwave-shell-mode-hook

Hook for customizing idlwave-shell-mode.

5.2 Using the Shell

The IDLWAVE shell works in the same fashion as other shell modes in Emacs. It provides command history, command line editing and job control. The UP and DOWN arrows cycle through the input history just like in an X terminal4. The history is preserved between emacs and IDL sessions. Here is a list of commonly used commands:

UP, M-pCycle backwards in input history
DOWN, M-nCycle forwards in input history
M-rPrevious input matching a regexp
M-sNext input matching a regexp
returnSend input or copy line to current prompt
C-c C-aBeginning of line; skip prompt
C-c C-uKill input to beginning of line
C-c C-wKill word before cursor
C-c C-cSend ^C
C-c C-zSend ^Z
C-c C-\Send ^\
C-c C-oDelete last batch of process output
C-c C-rShow last batch of process output
C-c C-lList input history

In addition to these standard comint commands, idlwave-shell-mode provides many of the same commands which simplify writing IDL code available in IDLWAVE buffers. This includes abbreviations, online help, and completion. See Routine Info and Online Help and Completion for more information on these commands.

TABCompletion of file names (between quotes and after executive commands ‘.run’ and ‘.compile’), routine names, class names, keywords, system variables, system variable tags etc. (idlwave-shell-complete).
M-TABSame as TAB
C-c ?Routine Info display (idlwave-routine-info)
M-?IDL online help on routine (idlwave-routine-info-from-idlhelp)
C-c C-iUpdate routine info from buffers and shell (idlwave-update-routine-info)
C-c C-vFind the source file of a routine (idlwave-find-module)
C-c C-tFind the source file of a routine in the currently visited file (idlwave-find-module-this-file).
C-c =Compile a library routine (idlwave-resolve)
User Option: idlwave-shell-arrows-do-history (t)

Non-nil means UP and DOWN arrows move through command history like xterm.

User Option: idlwave-shell-comint-settings

Alist of special settings for the comint variables in the IDLWAVE Shell.

User Option: idlwave-shell-file-name-chars

The characters allowed in file names, as a string. Used for file name completion.

User Option: idlwave-shell-graphics-window-size

Size of IDL graphics windows popped up by special IDLWAVE command.

IDLWAVE works in line input mode: you compose a full command line (or multiple lines; see below), using all the power Emacs gives you to do this. When you press RET, the whole line is sent to IDL. Sometimes it is necessary to send single characters (without a newline), for example when an IDL program is waiting for single character input with the GET_KBRD function. You can send a single character to IDL with the command C-c C-x (idlwave-shell-send-char). When you press C-c C-y (idlwave-shell-char-mode-loop), IDLWAVE runs a blocking loop which accepts characters and immediately sends them to IDL. The loop can be exited with C-g. It terminates also automatically when the current IDL command is finished. Check the documentation of the two variables described below for a way to make IDL programs trigger automatic switches of the input mode.

User Option: idlwave-shell-use-input-mode-magic (nil)

Non-nil means IDLWAVE should check for input mode spells in output.

User Option: idlwave-shell-input-mode-spells

The three regular expressions which match the “magic spells” for input modes.

5.3 Multi-Line Commands

IDLWAVE can edit and send groups of commands built from multiple lines directly in the shell in many ways. A main level routine (without a ‘pro’ or ‘function’ routine definition statement, but with an ‘END’) can be compiled, or a batch routine or selected region can be run (see Compiling Programs). Or, as discussed in this section, multi-line commands can be entered directly into the IDLWAVE shell, and saved and recalled on the history stack.

Hitting RET at the end of a command in the shell sends the command text between the last prompt and the cursor. To build up multi-line commands, use, e.g., C-j. By default, each line is sent, one at a time, to the IDL process as a separate command. As in IDL batch files, however, no multi-line control statements are allowed (e.g. FOR...BEGIN..ENDFOR). To group multi-line control or other statement together as a single command, use an ‘&’ at the end of each line, e.g.:

IDL> for i=0,3 do begin &
print,i,' is fun' &
print,i^2,' is even more fun' &

Note that this is identical syntax to an IDL batch file. Use C-c SPACE to insert a ‘&’ and newline together. As in an IDLWAVE buffer, M-RET will add a continuation character (‘$’) and new line for a continued single command. With a combination of C-c SPACE and M-RET, complex multi-line commands can be built, e.g.:

IDL> for i=1,20 do begin &
print,'Now is the time for all good men to come to the aid of their number ', $
strtrim(i,2),' countries' &
endfor &
print,'(Right now)'

As usual, RET at the very end will send the multi-line command. By default, moving through history (see Using the Shell) with the arrow keys will not inhibit movement within multi-line commands, for ease of editing. Holding SHIFT while using the arrow keys will override this behavior; the command history will be cycled through directly.

5.4 Commands Sent to the Shell

The IDLWAVE buffers and shell interact very closely. In addition to the normal commands you enter at the IDL> prompt, many other special commands are sent to the shell, sometimes as a direct result of invoking a key command, menu item, or toolbar button, but also automatically, as part of the normal flow of information updates between the buffer and shell.

The commands sent include breakpoint, .step and other debug commands (see Debugging IDL Programs), .run and other compilation statements (see Compiling Programs), examination commands like print and help (see Examining Variables), and other special purpose commands designed to keep information on the running shell current.

By default, much of this background shell input and output is hidden from the user, but this is configurable. The custom variable idlwave-abbrev-show-commands allows you to configure which commands sent to the shell are shown there. For a related customization for separating the output of examine commands, see Examining Variables.

User Option: idlwave-shell-show-commands ('(run misc breakpoint))

A list of command types to echo in the shell when sent. Possible values are run for .run, .compile and other run commands, misc for lesser used commands like window, retall,close, etc., breakpoint for breakpoint setting and clearing commands, and debug for other debug, stepping, and continue commands. In addition, if the variable is set to the single symbol 'everything, all the copious shell input is displayed (which is probably only useful for debugging purposes). N.B. For hidden commands which produce output by side-effect, that output remains hidden (e.g., stepping through a print command). As a special case, any error message in the output will be displayed (e.g., stepping to an error).

5.5 Debugging IDL Programs

Programs can be compiled, run, and debugged directly from the source buffer in Emacs, walking through arbitrarily deeply nested code, printing expressions and skipping up and down the calling stack along the way. IDLWAVE makes compiling and debugging IDL programs far less cumbersome by providing a full-featured, key/menu/toolbar-driven interface to commands like breakpoint, .step, .run, etc. It can even perform complex debug operations not natively supported by IDL (like continuing to the line at the cursor).

The IDLWAVE shell installs key bindings both in the shell buffer and in all IDL code buffers of the current Emacs session, so debug commands work in both places (in the shell, commands operate on the last file compiled). On Emacs versions which support it, a debugging toolbar is also installed. The toolbar display can be toggled with C-c C-d C-t (idlwave-shell-toggle-toolbar).

User Option: idlwave-shell-use-toolbar (t)

Non-nil means use the debugging toolbar in all IDL related buffers.

5.5.1 A Tale of Two Modes

The many debugging, compiling, and examination commands provided in IDLWAVE are available simultaneously through two different interfaces: the original, multi-key command interface, and the new Electric Debug Mode. The functionality they offer is similar, but the way you interact with them is quite different. The main difference is that, in Electric Debug Mode, the source buffers are made read-only, and single key-strokes are used to step through, examine expressions, set and remove breakpoints, etc. The same variables, prefix arguments, and settings apply to both versions, and both can be used interchangeably. By default, when breakpoints are hit, Electric Debug Mode is enabled. The traditional interface is described first. See Electric Debug Mode, for more on that mode. Note that electric debug mode can be prevented from activating automatically by customizing the variable idlwave-shell-automatic-electric-debug.

5.5.2 Debug Key Bindings

The standard debugging key bindings are always available by default on the prefix key C-c C-d, so, for example, setting a breakpoint is done with C-c C-d C-b, and compiling a source file with C-c C-d C-c. You can also easily configure IDLWAVE to use one or more modifier keys not in use by other commands, in lieu of the prefix C-c C-d (though these bindings will typically also be available; see idlwave-shell-activate-prefix-keybindings). For example, if you include in .emacs:

(setq idlwave-shell-debug-modifiers '(control shift))

a breakpoint can then be set by pressing b while holding down shift and control keys, i.e., C-S-b. Compiling a source file will be on C-S-c, deleting a breakpoint C-S-d, etc. In the remainder of this chapter we will assume that the C-c C-d bindings are active, but each of these bindings will have an equivalent shortcut if modifiers are given in the idlwave-shell-debug-modifiers variable (see Lesson II: Customization). A much simpler and faster form of debugging for running code is also available by default; see Electric Debug Mode.

User Option: idlwave-shell-prefix-key (C-c C-d)

The prefix key for the debugging map idlwave-shell-mode-prefix-map.

User Option: idlwave-shell-activate-prefix-keybindings (t)

Non-nil means debug commands will be bound to the prefix key, like C-c C-d C-b.

User Option: idlwave-shell-debug-modifiers (nil)

List of modifier keys to use for additional, alternative binding of debugging commands in the shell and source buffers. Can be one or more of control, meta, super, hyper, alt, and shift.

5.5.3 Breakpoints and Stepping

IDLWAVE helps you set breakpoints and step through code. Setting a breakpoint in the current line of the source buffer is accomplished with C-c C-d C-b (idlwave-shell-break-here). With a prefix arg of 1 (i.e., C-1 C-c C-d C-b), the breakpoint gets a /ONCE keyword, meaning that it will be deleted after first use. With a numeric prefix greater than one (e.g., C-4 C-c C-d C-b), the breakpoint will only be active the nth time it is hit. With a single non-numeric prefix (i.e., C-u C-c C-d C-b), prompt for a condition: an IDL expression to be evaluated and trigger the breakpoint only if true. To clear the breakpoint in the current line, use C-c C-d C-d (idlwave-clear-current-bp). When executed from the shell window, the breakpoint where IDL is currently stopped will be deleted. To clear all breakpoints, use C-c C-d C-a (idlwave-clear-all-bp). Breakpoints can also be disabled and re-enabled: C-c C-d C-\ (idlwave-shell-toggle-enable-current-bp).

Breakpoint lines are highlighted or indicated with an icon in the source code (different icons for conditional, after, and other break types). Disabled breakpoints are grayed out by default. Note that IDL places breakpoints as close as possible on or after the line you specify. IDLWAVE queries the shell for the actual breakpoint location which was set, so the exact line you specify may not be marked. You can re-sync the breakpoint list and update the display at any time (e.g., if you add or remove some on the command line) using C-c C-d C-l.

In recent IDLWAVE versions, the breakpoint line is highlighted when the mouse is moved over it, and a tooltip pops up describing the break details. mouse-3 on the breakpoint line pops up a menu of breakpoint actions, including clearing, disabling, and adding or changing break conditions or “after” break count.

Once the program has stopped somewhere, you can step through it. The most important stepping commands are C-c C-d C-s to execute one line of IDL code ("step into"); C-c C-d C-n to step a single line, treating procedure and function calls as a single step ("step over"); C-c C-d C-h to continue execution to the line at the cursor and C-c C-d C-r to continue execution. See Commands Sent to the Shell, for information on displaying or hiding the breakpoint and stepping commands the shell receives. Here is a summary of the breakpoint and stepping commands:

C-c C-d C-bSet breakpoint (idlwave-shell-break-here)
C-c C-d C-iSet breakpoint in module named here (idlwave-shell-break-in)
C-c C-d C-dClear current breakpoint (idlwave-shell-clear-current-bp)
C-c C-d C-aClear all breakpoints (idlwave-shell-clear-all-bp)
C-c C-d [Go to the previous breakpoint (idlwave-shell-goto-previous-bp)
C-c C-d ]Go to the next breakpoint (idlwave-shell-goto-next-bp)
C-c C-d C-\Disable/Enable current breakpoint (idlwave-shell-toggle-enable-current-bp)
C-c C-d C-jSet a breakpoint at the beginning of the enclosing routine.
C-c C-d C-sStep, into function calls (idlwave-shell-step)
C-c C-d C-nStep, over function calls (idlwave-shell-stepover)
C-c C-d C-kSkip one statement (idlwave-shell-skip)
C-c C-d C-uContinue to end of block (idlwave-shell-up)
C-c C-d C-mContinue to end of function (idlwave-shell-return)
C-c C-d C-oContinue past end of function (idlwave-shell-out)
C-c C-d C-hContinue to line at cursor position (idlwave-shell-to-here)
C-c C-d C-rContinue execution to next breakpoint, if any (idlwave-shell-cont)
C-c C-d C-upShow higher level in calling stack (idlwave-shell-stack-up)
C-c C-d C-downShow lower level in calling stack (idlwave-shell-stack-down)

All of these commands have equivalents in Electric Debug Mode, which provides faster single-key access (see Electric Debug Mode).

The line where IDL is currently stopped, at breakpoints, halts, and errors, etc., is marked with a color overlay or arrow, depending on the setting in idlwave-shell-mark-stop-line. If an overlay face is used to mark the stop line (as it is by default), when stepping through code, the face color is temporarily changed to gray, until IDL completes the next command and moves to the new line.

User Option: idlwave-shell-mark-breakpoints (t)

Non-nil means mark breakpoints in the source file buffers. The value indicates the preferred method. Valid values are nil, t, face, and glyph.

User Option: idlwave-shell-breakpoint-face

The face for breakpoint lines in the source code if idlwave-shell-mark-breakpoints has the value face.

User Option: idlwave-shell-breakpoint-popup-menu (t)

Whether to pop-up a menu and present a tooltip description on breakpoint lines.

User Option: idlwave-shell-mark-stop-line (t)

Non-nil means mark the source code line where IDL is currently stopped. The value specifies the preferred method. Valid values are nil, t, arrow, and face.

User Option: idlwave-shell-overlay-arrow (">")

The overlay arrow to display at source lines where execution halts, if configured in idlwave-shell-mark-stop-line.

User Option: idlwave-shell-stop-line-face

The face which highlights the source line where IDL is stopped, if configured in idlwave-shell-mark-stop-line.

5.5.4 Compiling Programs

In order to compile the current buffer under the IDLWAVE shell, press C-c C-d C-c (idlwave-save-and-run). This first saves the current buffer and then sends the command ‘.run path/to/file’ to the shell. You can also execute C-c C-d C-c from the shell buffer, in which case the most recently compiled buffer will be saved and re-compiled.

When developing or debugging a program, it is often necessary to execute the same command line many times. A convenient way to do this is C-c C-d C-y (idlwave-shell-execute-default-command-line). This command sends a default command line to the shell. If none has been set, you’ll be prompted to enter one. To edit the default command line again, call idlwave-shell-execute-default-command-line with a prefix argument: C-u C-c C-d C-y. If you give two prefix arguments, the last command on the comint input history is sent.

For quickly compiling and running the currently marked region as a main level program C-c C-d C-e (idlwave-shell-run-region) is very useful. A temporary file is created holding the contents of the current region (with END appended), and run from the shell.

5.5.5 Walking the Calling Stack

While debugging a program, it can be very useful to check the context in which the current routine was called, for instance to help understand the value of the arguments passed. To do so conveniently you need to examine the calling stack. If execution is stopped somewhere deep in a program, you can use the commands C-c C-d C-UP (idlwave-shell-stack-up) and C-c C-d C-DOWN (idlwave-shell-stack-down), or the corresponding toolbar buttons, to move up or down through the calling stack. The mode line of the shell window will indicate the position within the stack with a label like ‘[-3:MYPRO]’. The line of IDL code at that stack position will be highlighted. If you continue execution, IDLWAVE will automatically return to the current level. See Examining Variables, for information how to examine the value of variables and expressions on higher calling stack levels.

5.5.6 Electric Debug Mode

Even with a convenient debug key prefix enabled, repetitive stepping, variable examination (see Examining Variables), and other debugging activities can be awkward and slow using commands which require multiple keystrokes. Luckily, there’s a better way, inspired by the lisp e-debug mode, and available through the Electric Debug Mode. By default, as soon as a breakpoint is hit, this minor mode is enabled. The buffer showing the line where execution has halted is switched to Electric Debug Mode. This mode is visible as ‘*Debugging*’ in the mode line, and a different face (violet by default, if color is available) for the line stopped at point. The buffer is made read-only and single-character bindings for the most commonly used debugging commands are enabled. These character commands (a list of which is available with C-?) are:

aClear all breakpoints (idlwave-shell-clear-all-bp)
bSet breakpoint, C-u b for a conditional break, C-n b for nth hit (idlwave-shell-break-here)
dClear current breakpoint (idlwave-shell-clear-current-bp)
ePrompt for expression to print (idlwave-shell-clear-current-bp).
hContinue to the line at cursor position (idlwave-shell-to-here)
iSet breakpoint in module named here (idlwave-shell-break-in)
[Go to the previous breakpoint in the file (idlwave-shell-goto-previous-bp)
]Go to the next breakpoint in the file (idlwave-shell-goto-next-bp)
\Disable/Enable current breakpoint (idlwave-shell-toggle-enable-current-bp)
jSet breakpoint at beginning of enclosing routine (idlwave-shell-break-this-module)
kSkip one statement (idlwave-shell-skip)
mContinue to end of function (idlwave-shell-return)
nStep, over function calls (idlwave-shell-stepover)
oContinue past end of function (idlwave-shell-out)
pPrint expression near point or in region with C-u p (idlwave-shell-print)
qEnd the debugging session and return to the Shell’s main level (idlwave-shell-retall)
rContinue execution to next breakpoint, if any (idlwave-shell-cont)
s or SPACEStep, into function calls (idlwave-shell-step)
tPrint a calling-level traceback in the shell
uContinue to end of block (idlwave-shell-up)
vTurn Electric Debug Mode off (idlwave-shell-electric-debug-mode)
xExamine expression near point (or in region with C-u x) with shortcut of examine type.
zReset IDL (idlwave-shell-reset)
+ or =Show higher level in calling stack (idlwave-shell-stack-up)
- or _Show lower level in calling stack (idlwave-shell-stack-down)
?Help on expression near point or in region with C-u ? (idlwave-shell-help-expression)
C-?Show help on the commands available.

Most single-character electric debug bindings use the final keystroke of the equivalent multiple key commands (which are of course also still available), but some differ (e.g., e,t,q,x). Some have additional convenience bindings (like SPACE for stepping). All prefix and other argument options described in this section for the commands invoked by electric debug bindings are still valid. For example, C-u b sets a conditional breakpoint, just as it did with C-u C-c C-d C-b.

You can toggle the electric debug mode at any time in a buffer using C-c C-d C-v (v to turn it off while in the mode), or from the Debug menu. Normally the mode will be enabled and disabled at the appropriate times, but occasionally you might want to edit a file while still debugging it, or switch to the mode for conveniently setting lots of breakpoints.

To quickly abandon a debugging session and return to normal editing at the Shell’s main level, use q (idlwave-shell-retall). This disables electric debug mode in all IDLWAVE buffers5. Help is available for the command shortcuts with C-?. If you find this mode gets in your way, you can keep it from automatically activating by setting the variable idlwave-shell-automatic-electric-debug to nil, or 'breakpoint. If you’d like the convenient electric debug shortcuts available also when run-time errors are encountered, set to t.

User Option: idlwave-shell-automatic-electric-debug ('breakpoint)

Whether to enter electric debug mode automatically when a breakpoint or run-time error is encountered, and then disable it in all buffers when the $MAIN$ level is reached (either through normal program execution, or retall). In addition to nil for never, and t for both breakpoints and errors, this can be 'breakpoint (the default) to enable it only at breakpoint halts.

User Option: idlwave-shell-electric-stop-color (Violet)

Default color of the stopped line overlay when in electric debug mode.

User Option: idlwave-shell-electric-stop-line-face

The face to use for the stopped line. Defaults to a face similar to the modeline, with color idlwave-shell-electric-stop-color.

User Option: idlwave-shell-electric-zap-to-file (t)

If set, when entering electric debug mode, select the window displaying the file where point is stopped. This takes point away from the shell window, but is useful for immediate stepping, etc.

5.6 Examining Variables

Do you find yourself repeatedly typing, e.g., print,n_elements(x), and similar statements to remind yourself of the type/size/structure/value/etc. of variables and expressions in your code or at the command line? IDLWAVE has a suite of special commands to automate these types of variable or expression examinations. They work by sending statements to the shell formatted to include the indicated expression, and can be accessed in several ways.

These examine commands can be used in the shell or buffer at any time (as long as the shell is running), and are very useful when execution is stopped in a buffer due to a triggered breakpoint or error, or while composing a long command in the IDLWAVE shell. In the latter case, the command is sent to the shell and its output is visible, but point remains unmoved in the command being composed: you can inspect the constituents of a command you’re building without interrupting the process of building it! You can even print arbitrary expressions from older input or output further up in the shell window; any expression, variable, number, or function you see can be examined.

If the variable idlwave-shell-separate-examine-output is non-nil (the default), all examine output will be sent to a special *Examine* buffer, rather than the shell. The output of prior examine commands is saved in this buffer. In this buffer c clears the contents, and q hides the buffer.

The two most basic examine commands are bound to C-c C-d C-p, to print the expression at point, and C-c C-d ?, to invoke help on this expression6. The expression at point is either an array expression or a function call, or the contents of a pair of parentheses. The chosen expression is highlighted, and simultaneously the resulting output is highlighted in the shell or separate output buffer. Calling the above commands with a prefix argument will use the current region as expression instead of using the one at point. which can be useful for examining complicated, multi-line expressions. Two prefix arguments (C-u C-u C-c C-d C-p) will prompt for an expression to print directly. By default, when invoking print, only an initial portion of long arrays will be printed, up to idlwave-shell-max-print-length.

For added speed and convenience, there are mouse bindings which allow you to click on expressions and examine their values. Use S-mouse-2 to print an expression and C-M-mouse-2 to invoke help (i.e., you need to hold down META and CONTROL while clicking with the middle mouse button). If you simply click, the nearest expression will be selected in the same manner as described above. You can also drag the mouse in order to highlight exactly the specific expression or sub-expression you want to examine. For custom expression examination, and the powerful customizable pop-up examine selection, See Custom Expression Examination.

The same variable inspection commands work both in the IDL Shell and IDLWAVE buffers, and even for variables at higher levels of the calling stack. For instance, if you’re stopped at a breakpoint in a routine, you can examine the values of variables and expressions inside its calling routine, and so on, all the way up through the calling stack. Simply step up the stack, and print variables as you see them (see Walking the Calling Stack, for information on stepping back through the calling stack). The following restrictions apply for all levels except the current:

  • Array expressions must use the ‘[ ]’ index delimiters. Identifiers with a ‘( )’ will be interpreted as function calls.
  • N.B.: printing values of expressions on higher levels of the calling stack uses the unsupported IDL routine ROUTINE_NAMES, which may or may not be available in future versions of IDL. Caveat Examinor.
User Option: idlwave-shell-expression-face

The face for idlwave-shell-expression-overlay. Allows you to choose the font, color and other properties for the expression printed by IDL.

User Option: idlwave-shell-output-face

The face for idlwave-shell-output-overlay. Allows you to choose the font, color and other properties for the most recent output of IDL when examining an expression."

User Option: idlwave-shell-separate-examine-output (t)

If non-nil, re-direct the output of examine commands to a special *Examine* buffer, instead of in the shell itself.

User Option: idlwave-shell-max-print-length (200)

The maximum number of leading array entries to print, when examining array expressions.

5.7 Custom Expression Examination

The variety of possible variable and expression examination commands is endless (just look, for instance, at the keyword list to widget_info()). Rather than attempt to include them all, IDLWAVE provides two easy methods to customize your own commands, with a special mouse examine command, and two macros for generating your own examine key and mouse bindings.

The most powerful and flexible mouse examine command of all is available on C-S-mouse-2. Just as for all the other mouse examine commands, it permits click or drag expression selection, but instead of sending hard-coded commands to the shell, it pops-up a customizable selection list of examine functions to choose among, configured with the idlwave-shell-examine-alist variable7. This variable is a list of key-value pairs (an alist in Emacs parlance), where the key gives a name to be shown for the examine command, and the value is the command strings itself, in which the text ___ (three underscores) will be replaced by the selected expression before being sent to the shell. An example might be key Structure Help with value help,___,/STRUCTURE. In that case, you’d be prompted with Structure Help, which might send something like help,var,/STRUCTURE to the shell for output. idlwave-shell-examine-alist comes configured by default with a large list of examine commands, but you can easily customize it to add your own.

In addition to configuring the functions available to the pop-up mouse command, you can easily create your own customized bindings to inspect expressions using the two convenience macros idlwave-shell-examine and idlwave-shell-mouse-examine. These create keyboard or mouse-based custom inspections of variables, sharing all the same properties of the built-in examine commands. Both functions take a single string argument sharing the syntax of the idlwave-shell-examine-alist values, e.g.:

(add-hook 'idlwave-shell-mode-hook
          (lambda ()
            (idlwave-shell-define-key-both [s-down-mouse-2]
                                  "print, size(___,/DIMENSIONS)"))
            (idlwave-shell-define-key-both [f9] (idlwave-shell-examine
                                       "print, size(___,/DIMENSIONS)"))
            (idlwave-shell-define-key-both [f10] (idlwave-shell-examine
            (idlwave-shell-define-key-both [f11] (idlwave-shell-examine

Now pressing f9, or middle-mouse dragging with the SUPER key depressed, will print the dimensions of the nearby or highlighted expression. Pressing f10 will give the type string, and f11 will show the contents of a nearby structure. As you can see, the possibilities are only marginally finite.

User Option: idlwave-shell-examine-alist

An alist of examine commands in which the keys name the command and are displayed in the selection pop-up, and the values are custom IDL examine command strings to send, after all instances of ___ (three underscores) are replaced by the indicated expression.

6 Installation

6.1 Installing IDLWAVE

IDLWAVE is part of Emacs 21.1 and later. It is also an XEmacs package and can be installed from the XEmacs ftp site with the normal package management system on XEmacs 21. You can also download IDLWAVE and install it yourself from the maintainers webpage. Follow the instructions in the INSTALL file.

6.2 Installing Online Help

Starting with IDL v6.2, all necessary online help files and routine information are distributed directly with IDL. Nothing additional is required.

For version of IDL prior to 6.2 (and IDLWAVE prior to version 6.0), if you want to use the online help display, an additional set of files (HTML versions of the IDL documentation) must be installed. These files can also be downloaded from the maintainers webpage. You need to place the files somewhere on your system and tell IDLWAVE where they are with:

; e.g. /usr/local/etc/
(setq idlwave-html-help-location "/path/to/help/dir/")

The default location is /usr/local/etc, and if you install the directory there, you do not need to set this variable. Note that the help package only changes with new versions of the IDL documentation, and need not be updated unless your version of IDL changes. Since the help system is distributed with IDL starting at version 6.2, no new help packages will be created for these versions.

7 Acknowledgments

The main contributors to the IDLWAVE package have been:

The following people have also contributed to the development of IDLWAVE with patches, ideas, bug reports and suggestions.

Doug Dirks was instrumental in providing the crucial IDL XML catalog to support HTML help with IDL v6.2 and later, and Ali Bahrami provided scripts and documentation to interface with the IDL Assistant.

Thanks to everyone!

Appendix A Sources of Routine Info

In Routine Info and Completion we showed how IDLWAVE displays the calling sequence and keywords of routines, and completes routine names and keywords. For these features to work, IDLWAVE must know about the accessible routines.

A.1 Routine Definitions

Routines which can be used in an IDL program can be defined in several places:

  1. Builtin routines are defined inside IDL itself. The source code of such routines is not available, but instead are learned about through the IDL documentation.
  2. Routines which are part of the current program, are defined in a file explicitly compiled by the user. This file may or may not be located on the IDL search path.
  3. Library routines are defined in files located on IDL’s search path. When a library routine is called for the first time, IDL will find the source file and compile it dynamically. A special sub-category of library routines are the system routines distributed with IDL, and usually available in the lib subdirectory of the IDL distribution.
  4. External routines written in other languages (like Fortran or C) can be called with CALL_EXTERNAL, linked into IDL via LINKIMAGE, or included as dynamically loaded modules (DLMs). Currently IDLWAVE cannot provide routine info and completion for such external routines, except by querying the Shell for calling information (DLMs only).

A.2 Routine Information Sources

To maintain the most comprehensive information about all IDL routines on a system, IDLWAVE collects data from many sources:

  1. It has a builtin list with information about the routines IDL ships with. IDLWAVE 6.5.2 is distributed with a list of 2611 routines and object methods, reflecting IDL version 9.0. As of IDL v6.2, the routine info is distributed directly with IDL in the form of an XML catalog which IDLWAVE scans. Formerly, this list was created (imperfectly) by scanning the IDL manuals to produce the file idlw-rinfo.el.
  2. IDLWAVE scans all its buffers in the current Emacs session for routine definitions. This is done automatically when routine information or completion is first requested by the user. Each new buffer and each buffer saved after making changes is also scanned. The command C-c C-i (idlwave-update-routine-info) can be used at any time to rescan all buffers.
  3. If you have an IDLWAVE-Shell running in the Emacs session, IDLWAVE will query the shell for compiled routines and their arguments. This happens automatically when routine information or completion is first requested by the user. Each time an Emacs buffer is compiled with C-c C-d C-c, the routine info for that file is queried. Though rarely necessary, the command C-c C-i (idlwave-update-routine-info) can be used to explicitly update the shell routine data.
  4. Many popular libraries are distributed with routine information already scanned into library catalogs (see Library Catalogs). These per-directory catalog files can also be built by the user with the supplied idlwave_catalog tool. They are automatically discovered by IDLWAVE.
  5. IDLWAVE can scan selected directories of source files and store the result in a single user catalog file which will be automatically loaded just like idlw-rinfo.el. See User Catalog, for information on how to scan files in this way.

Loading all the routine and catalog information can be a time consuming process, especially over slow networks. Depending on the system and network configuration it could take up to 30 seconds (though locally on fast systems is usually only a few seconds). In order to minimize the wait time upon your first completion or routine info command in a session, IDLWAVE uses Emacs idle time to do the initialization in six steps, yielding to user input in between. If this gets into your way, set the variable idlwave-init-rinfo-when-idle-after to 0 (zero). The more routines documented in library and user catalogs, the slower the loading will be, so reducing this number can help alleviate any long load times.

User Option: idlwave-init-rinfo-when-idle-after (10)

Seconds of idle time before routine info is automatically initialized.

User Option: idlwave-scan-all-buffers-for-routine-info (t)

Non-nil means scan all buffers for IDL programs when updating info.

User Option: idlwave-query-shell-for-routine-info (t)

Non-nil means query the shell for info about compiled routines.

User Option: idlwave-auto-routine-info-updates

Controls under what circumstances routine info is updated automatically.

A.3 Catalogs

Catalogs are files containing scanned information on individual routines, including arguments and keywords, calling sequence, file path, class and procedure vs. function type, etc. They represent a way of extending the internal built-in information available for IDL system routines (see Routine Info) to other source collections.

Starting with version 5.0, there are two types of catalogs available with IDLWAVE. The traditional user catalog and the newer library catalogs. Although they can be used interchangeably, the library catalogs are more flexible, and preferred. There are few occasions when a user catalog might be preferred—read below. Both types of catalogs can coexist without causing problems.

To facilitate the catalog systems, IDLWAVE stores information it gathers from the shell about the IDL search paths, and can write this information out automatically, or on-demand (menu Debug->Save Path Info). On systems with no shell from which to discover the path information (e.g., Windows), a library path must be specified in idlwave-library-path to allow library catalogs to be located, and to setup directories for user catalog scan (see User Catalog for more on this variable). Note that, before the shell is running, IDLWAVE can only know about the IDL search path by consulting the file pointed to by idlwave-path-file (~/.emacs.d/idlwave/idlpath.el, by default). If idlwave-auto-write-path is enabled (which is the default), the paths are written out whenever the IDLWAVE shell is started.

User Option: idlwave-auto-write-path (t)

Write out information on the !PATH and !DIR paths from IDL automatically when they change and when the Shell is closed. These paths are needed to locate library catalogs.

User Option: idlwave-library-path

IDL library path for Windows and macOS. Under Unix/macOS, will be obtained from the Shell when run.

User Option: idlwave-system-directory

The IDL system directory for Windows and macOS. Also needed for locating HTML help and the IDL Assistant for IDL v6.2 and later. Under Unix/macOS, will be obtained from the Shell and recorded, if run.

User Option: idlwave-config-directory (~/.emacs.d/idlwave)

Default path where IDLWAVE saves configuration information, a user catalog (if any), and a cached scan of the XML catalog (IDL v6.2 and later).

Next: , Up: Catalogs   [Contents][Index]

A.3.1 Library Catalogs

Library catalogs consist of files named .idlwave_catalog stored in directories containing .pro routine files. They are discovered on the IDL search path and loaded automatically when routine information is read. Each catalog file documents the routines found in that directory—one catalog per directory. Every catalog has a library name associated with it (e.g., AstroLib). This name will be shown briefly when the catalog is found, and in the routine info of routines it documents.

Many popular libraries of routines are shipped with IDLWAVE catalog files by default, and so will be automatically discovered. Library catalogs are scanned externally to Emacs using a tool provided with IDLWAVE. Each catalog can be re-scanned independently of any other. Catalogs can easily be made available system-wide with a common source repository, providing uniform routine information, and lifting the burden of scanning from the user (who may not even know they’re using a scanned catalog). Since all catalogs are independent, they can be re-scanned automatically to gather updates, e.g., in a cron job. Scanning is much faster than with the built-in user catalog method. One minor disadvantage: the entire IDL search path is scanned for catalog files every time IDLWAVE starts up, which might be slow if accessing IDL routines over a slow network.

A Perl tool to create library catalogs is distributed with IDLWAVE: idlwave_catalog. It can be called quite simply:

idlwave_catalog MyLib

This will scan all directories recursively beneath the current and populate them with .idlwave_catalog files, tagging the routines found there with the name library “MyLib”. The full usage information:

Usage: idlwave_catalog  [-l] [-v] [-d] [-s] [-f] [-h] libname
       libname - Unique name of the catalog (4 or more alphanumeric
            -l - Scan local directory only, otherwise recursively
                 catalog all directories at or beneath this one.
            -v - Print verbose information.
            -d - Instead of scanning, delete all .idlwave_catalog files
                 here or below.
            -s - Be silent.
            -f - Force overwriting any catalogs found with a different
                 library name.
            -h - Print this usage.

To re-load the library catalogs on the IDL path, force a system routine info update using a single prefix to idlwave-update-routine-info: C-u C-c C-i.

User Option: idlwave-use-library-catalogs (t)

Whether to search for and load library catalogs. Disable if load performance is a problem and/or the catalogs are not needed.

Previous: , Up: Catalogs   [Contents][Index]

A.3.2 User Catalog

The user catalog is the old routine catalog system. It is produced within Emacs, and stored in a single file in the user’s home directory (.emacs.d/idlwave/idlusercat.el by default). Although library catalogs are more flexible, there may be reasons to prefer a user catalog instead, including:

  • The scan is internal to Emacs, so you don’t need a working Perl installation, as you do for library catalogs.
  • Can be used to scan directories for which the user has no write privileges.
  • Easy widget-based path selection.

However, no routine info is available in the user catalog by default; the user must actively complete a scan. In addition, this type of catalog is all or nothing: if a single routine changes, the entire catalog must be rescanned to update it. Creating the user catalog is also much slower than scanning library catalogs.

You can scan any of the directories on the currently known path. Under Windows, you need to specify the IDL search path in the variable idlwave-library-path, and the location of the IDL directory (the value of the !DIR system variable) in the variable idlwave-system-directory, like this8:

(setq idlwave-library-path
        '("+c:/RSI/IDL56/lib/" "+c:/user/me/idllibs"))
(setq idlwave-system-directory "c:/RSI/IDL56/")

Under GNU/Linux and UNIX, these values will be automatically gathered from the IDLWAVE shell, if run.

The command M-x idlwave-create-user-catalog-file (or the menu item ‘IDLWAVE->Routine Info->Select Catalog Directories’) can then be used to create a user catalog. It brings up a widget in which you can select some or all directories on the search path. Directories which already contain a library catalog are marked with ‘[LIB]’, and need not be scanned (although there is no harm if you do so, other than the additional memory used for the duplication).

After selecting directories, click on the ‘[Scan & Save] button in the widget to scan all files in the selected directories and write out the resulting routine information. In order to update the library information using the directory selection, call the command idlwave-update-routine-info with a double prefix argument: C-u C-u C-c C-i. This will rescan files in the previously selected directories, write an updated version of the user catalog file and rebuild IDLWAVE’s internal lists. If you give three prefix arguments C-u C-u C-u C-c C-i, updating will be done with a background job9. You can continue to work, and the library catalog will be re-read when it is ready. If you find you need to update the user catalog often, you should consider building a library catalog for your routines instead (see Library Catalogs).

User Option: idlwave-special-lib-alist

Alist of regular expressions matching special library directories for labeling in routine-info display.

A.4 Load-Path Shadows

IDLWAVE can compile a list of routines which are (re-)defined in more than one file. Since one definition will hide (shadow) the others depending on which file is compiled first, such multiple definitions are called "load-path shadows". IDLWAVE has several routines to scan for load path shadows. The output is placed into the special buffer *Shadows*. The format of the output is identical to the source section of the routine info buffer (see Routine Info). The different definitions of a routine are ordered by likelihood of use. So the first entry will be most likely the one you’ll get if an unsuspecting command uses that routine. Before listing shadows, you should make sure that routine info is up-to-date by pressing C-c C-i. Here are the different routines (also available in the Menu ‘IDLWAVE->Routine Info’):

M-x idlwave-list-buffer-load-path-shadows

This command checks the names of all routines defined in the current buffer for shadowing conflicts with other routines accessible to IDLWAVE. The command also has a key binding: C-c C-b

M-x idlwave-list-shell-load-path-shadows.

Checks all routines compiled under the shell for shadowing. This is very useful when you have written a complete application. Just compile the application, use RESOLVE_ALL to compile any routines used by your code, update the routine info inside IDLWAVE with C-c C-i and then check for shadowing.

M-x idlwave-list-all-load-path-shadows

This command checks all routines accessible to IDLWAVE for conflicts.

For these commands to work fully you need to scan the entire load path in either a user or library catalog. Also, IDLWAVE should be able to distinguish between the system library files (normally installed in /usr/local/rsi/idl/lib) and any site specific or user specific files. Therefore, such local files should not be installed inside the lib directory of the IDL directory. This is also advisable for many other reasons.

Users of Windows also must set the variable idlwave-system-directory to the value of the !DIR system variable in IDL. IDLWAVE appends lib to the value of this variable and assumes that all files found on that path are system routines.

Another way to find out if a specific routine has multiple definitions on the load path is routine info display (see Routine Info).

A.5 Documentation Scan

Starting with version 6.2, IDL is distributed directly with HTML online help, and an XML-based catalog of routine information. This makes scanning the manuals with the tool get_html_rinfo, and the idlw-rinfo.el file it produced, as described here, entirely unnecessary. The information is left here for users wishing to produce a catalog of older IDL versions’ help.

IDLWAVE derives its knowledge about system routines from the IDL manuals. The file idlw-rinfo.el contains the routine information for the IDL system routines, and links to relevant sections of the HTML documentation. The Online Help feature of IDLWAVE requires HTML versions of the IDL manuals to be available; the HTML documentation is not distributed with IDLWAVE by default, but must be downloaded separately from the maintainers webpage.

The HTML files and related images can be produced from the idl.chm HTMLHelp file distributed with IDL using the free Microsoft HTML Help Workshop. If you are lucky, the maintainer of IDLWAVE will always have access to the newest version of IDL and provide updates. The IDLWAVE distribution also contains the Perl program get_html_rinfo which constructs the idlw-rinfo.el file by scanning the HTML documents produced from the IDL documentation. Instructions on how to use get_html_rinfo are in the program itself.

Appendix B HTML Help Browser Tips

The following information pertains to IDL versions >=5.0 and <7.0. With IDL v7.0, the IDL Assistant was dropped in favor of the Eclipse-based help system, and IDL is no longer distributed with the raw HTML help files.

There are a wide variety of possible browsers to use for displaying the online HTML help available with IDLWAVE (starting with version 5.0). Since IDL v6.2, a single cross-platform HTML help browser, the IDL Assistant is distributed with IDL. If this help browser is available, it is the preferred choice, and the default. The variable idlwave-help-use-assistant, enabled by default, controls whether this help browser is used. If you use the IDL Assistant, the tips here are not relevant.

Since IDLWAVE runs on many different system types, a single browser configuration is not possible, but choices abound. The default idlwave-help-browser-function inherits the browser configured in browse-url-browser-function.

Note that the HTML files recompiled from the help sources contain specific references to the ‘Symbol’ font, which by default is not permitted in normal encodings (it’s invalid, technically). Though it only impacts a few symbols, you can trick Mozilla-based browsers into recognizing ‘Symbol’ by following the directions here. With this fix in place, HTML help pages look almost identical to their PDF equivalents (yet can be bookmarked, browsed as history, searched, etc.).

Appendix C Configuration Examples

Question: You have all these complicated configuration options in your package, but which ones do you as the maintainer actually set in your own configuration?

Answer: Not many, beyond custom key bindings. I set most defaults the way that seems best. However, the default settings do not turn on features which:

To see what I mean, here is the entire configuration the old maintainer had in his .emacs:

(setq idlwave-shell-debug-modifiers '(control shift)
      idlwave-store-inquired-class t
      idlwave-shell-automatic-start t
      idlwave-main-block-indent 2
      idlwave-init-rinfo-when-idle-after 2
      idlwave-help-dir "~/lib/emacs/idlwave"
      idlwave-special-lib-alist '(("/idl-astro/" . "AstroLib")
                                  ("/jhuapl/" . "JHUAPL-Lib")
                                  ("/dominik/lib/idl/" . "MyLib")))

However, if you are an Emacs power-user and want IDLWAVE to work completely differently, you can change almost every aspect of it. Here is an example of a much more extensive configuration of IDLWAVE. The user is King!

;;; Settings for IDLWAVE mode

(setq idlwave-block-indent 3)           ; Indentation settings
(setq idlwave-main-block-indent 3)
(setq idlwave-end-offset -3)
(setq idlwave-continuation-indent 1)
(setq idlwave-begin-line-comment "^;[^;]")  ; Leave ";" but not ";;"
                                            ; anchored at start of line.
(setq idlwave-surround-by-blank t)      ; Turn on padding ops =,<,>
(setq idlwave-pad-keyword nil)          ; Remove spaces for keyword '='
(setq idlwave-expand-generic-end t)     ; convert END to ENDIF etc...
(setq idlwave-reserved-word-upcase t)   ; Make reserved words upper case
                                        ; (with abbrevs only)
(setq idlwave-abbrev-change-case nil)   ; Don't force case of expansions
(setq idlwave-hang-indent-regexp ": ")  ; Change from "- " for auto-fill
(setq idlwave-show-block nil)           ; Turn off blinking to begin
(setq idlwave-abbrev-move t)            ; Allow abbrevs to move point
(setq idlwave-query-class '((method-default . nil) ; No query for method
                            (keyword-default . nil); or keyword completion
                            ("INIT" . t)           ; except for these
                            ("CLEANUP" . t)
                            ("SETPROPERTY" .t)
                            ("GETPROPERTY" .t)))

;; Using w3m for help (must install w3m and emacs-w3m)
(autoload 'w3m-browse-url "w3m" "Interface for w3m on Emacs." t)
(setq idlwave-help-browser-function 'w3m-browse-url
      w3m-use-tab nil ; no tabs, location line, or toolbar
      w3m-use-header-line nil
      w3m-use-toolbar nil)

;; Close my help window or frame when w3m closes with 'q'.
(defadvice w3m-close-window (after idlwave-close activate)
  (if (boundp 'idlwave-help-frame)

;; Some setting can only be done from a mode hook.  Here is an example:
(add-hook 'idlwave-mode-hook
  (lambda ()
    (setq case-fold-search nil)          ; Make searches case sensitive
    ;; Run other functions here
    (font-lock-mode 1)                   ; Turn on font-lock mode
    (idlwave-auto-fill-mode 0)           ; Turn off auto filling
    (setq idlwave-help-browser-function 'browse-url-w3)

    ;; Pad with 1 space (if -n is used then make the
    ;; padding a minimum of n spaces.)  The defaults use -1
    ;; instead of 1.
    (idlwave-action-and-binding "=" '(idlwave-expand-equal 1 1))
    (idlwave-action-and-binding "<" '(idlwave-surround 1 1))
    (idlwave-action-and-binding ">" '(idlwave-surround 1 1 '(?-)))
    (idlwave-action-and-binding "&" '(idlwave-surround 1 1))

    ;; Only pad after comma and with exactly 1 space
    (idlwave-action-and-binding "," '(idlwave-surround nil 1))
    (idlwave-action-and-binding "&" '(idlwave-surround 1 1))

    ;; Pad only after '->', remove any space before the arrow
    (idlwave-action-and-binding "->"  '(idlwave-surround 0 -1 nil 2))

    ;; Set some personal bindings
    ;; (In this case, makes ',' have the normal self-insert behavior.)
    (local-set-key "," 'self-insert-command)
    (local-set-key [f5] 'idlwave-shell-break-here)
    (local-set-key [f6] 'idlwave-shell-clear-current-bp)

    ;; Create a newline, indenting the original and new line.
    ;; A similar function that does _not_ reindent the original
    ;; line is on "\C-j" (The default for emacs programming modes).
    (local-set-key "\n" 'idlwave-newline)
    ;; (local-set-key "\C-j" 'idlwave-newline) ; My preference.

    ;; Some personal abbreviations
    (define-abbrev idlwave-mode-abbrev-table
      (concat idlwave-abbrev-start-char "wb") "widget_base()"
      (idlwave-keyword-abbrev 1))
    (define-abbrev idlwave-mode-abbrev-table
      (concat idlwave-abbrev-start-char "on") "obj_new()"
      (idlwave-keyword-abbrev 1))

;;; Settings for IDLWAVE SHELL mode

(setq idlwave-shell-overlay-arrow "=>")        ; default is ">"
(setq idlwave-shell-use-dedicated-frame t)     ; Make a dedicated frame
(setq idlwave-shell-prompt-pattern "^WAVE> ")  ; default is "^IDL> "
(setq idlwave-shell-explicit-file-name "wave")
(setq idlwave-shell-process-name "wave")
(setq idlwave-shell-use-toolbar nil)           ; No toolbar

;; Most shell interaction settings can be done from the shell-mode-hook.
(add-hook 'idlwave-shell-mode-hook
          (lambda ()
            ;; Set up some custom key and mouse examine commands
            (idlwave-shell-define-key-both [s-down-mouse-2]
                                  "print, size(___,/DIMENSIONS)"))
            (idlwave-shell-define-key-both [f9] (idlwave-shell-examine
                                       "print, size(___,/DIMENSIONS)"))
            (idlwave-shell-define-key-both [f10] (idlwave-shell-examine
            (idlwave-shell-define-key-both [f11] (idlwave-shell-examine

Appendix D Windows and macOS

IDLWAVE was developed on a UNIX system. However, thanks to the portability of Emacs, much of IDLWAVE does also work under different operating systems like Windows (with NTEmacs).

The only real problem is that there is no command-line version of IDL for Windows with which IDLWAVE can interact. As a result, the IDLWAVE Shell does not work and you have to rely on IDLDE to run and debug your programs. However, editing IDL source files with Emacs/IDLWAVE works with all bells and whistles, including routine info, completion and fast online help. Only a small amount of additional information must be specified in your .emacs file: the path names which, on a UNIX system, are automatically gathered by talking to the IDL program.

Here is an example of the additional configuration needed for a Windows system. I am assuming that IDLWAVE has been installed in ‘C:\Program Files\IDLWAVE and that IDL is installed in ‘C:\RSI\IDL63.

;; location of the lisp files (only needed if IDLWAVE is not part of
;; your default X/Emacs installation)
(setq load-path (cons "c:/program files/IDLWAVE" load-path))

;; The location of the IDL library directories, both standard,  and your own.
;; note that the initial "+" expands the path recursively
(setq idlwave-library-path
        '("+c:/RSI/IDL63/lib/" "+c:/path/to/my/idllibs" ))

;; location of the IDL system directory (try "print,!DIR")
(setq idlwave-system-directory "c:/RSI/IDL62/")

Furthermore, Windows sometimes tries to outsmart you; make sure you check the following things:

Windows users who’d like to make use of IDLWAVE’s context-aware HTML help can skip the browser and use the HTMLHelp functionality directly. See Help with HTML Documentation.

Appendix E Troubleshooting

Although IDLWAVE usually installs and works without difficulty, a few common problems and their solutions are documented below.

  1. Whenever an IDL error occurs or a breakpoint is hit, I get errors or strange behavior when I try to type anything into some of my IDLWAVE buffers.

    This is a feature, not an error. You’re in Electric Debug Mode (see Electric Debug Mode). You should see *Debugging* in the mode-line. The buffer is read-only and all debugging and examination commands are available as single keystrokes; C-? lists these shortcuts. Use q to quit the mode, and customize the variable idlwave-shell-automatic-electric-debug if you prefer not to enter electric debug on breakpoints… but you really should try it before you disable it! You can also customize this variable to enter debug mode when errors are encountered.

  2. I get errors like ‘Searching for program: no such file or directory, idl’ when attempting to start the IDL shell.

    IDLWAVE needs to know where IDL is in order to run it as a process. By default, it attempts to invoke it simply as ‘idl’, which presumes such an executable is on your search path. You need to ensure ‘idl’ is on your ‘$PATH’, or specify the full pathname to the idl program with the variable idlwave-shell-explicit-file-name. Note that you may need to set your shell search path in two places when running Emacs as an Aqua application with macOS; see the next topic.

  3. IDLWAVE is disregarding my ‘IDL_PATH’ which I set under macOS

    If you run Emacs directly as an Aqua application, rather than from the console shell, the environment is set not from your usual shell configuration files (e.g., .cshrc), but from the file ~/.MacOSX/environment.plist. Either include your path settings there, or start Emacs and IDLWAVE from the shell.

  4. M-TAB doesn’t complete words, it switches windows on my desktop.

    Your system is trapping M-TAB and using it for its own nefarious purposes: Emacs never sees the keystrokes. On many Unix systems, you can reconfigure your window manager to use another key sequence for switching among windows. Another option is to use the equivalent sequence ESC-TAB.

  5. When stopping at breakpoints or errors, IDLWAVE does not seem to highlight the relevant line in the source.

    IDLWAVE scans for error and halt messages and highlights the stop location in the correct file. However, if you’ve changed the system variable ‘!ERROR_STATE.MSG_PREFIX’, it is unable to parse these message correctly. Don’t do that.

  6. IDLWAVE doesn’t work correctly when using ENVI.

    Though IDLWAVE was not written with ENVI in mind, it works just fine with it, as long as you update the prompt it’s looking for (‘IDL> ’ by default). You can do this with the variable idlwave-shell-prompt-pattern (see Starting the Shell), e.g., in your .emacs:

    (setq idlwave-shell-prompt-pattern "^\r? ?\\(ENVI\\|IDL\\)> ")
  7. Attempts to set breakpoints fail: no breakpoint is indicated in the IDLWAVE buffer.

    IDL changed its breakpoint reporting format starting with IDLv5.5. The first version of IDLWAVE to support the new format is IDLWAVE v4.10. If you have an older version and are using IDL >v5.5, you need to upgrade, and/or make sure your recent version of IDLWAVE is being found on the Emacs load-path (see the next entry). You can list the version being used with C-h v idlwave-mode-version RET.

  8. I installed a new version of IDLWAVE, but the old version is still being used or IDLWAVE works, but when I tried to install the optional modules idlw-roprompt.el or idlw-complete-structtag, I get errors like ‘Cannot open load file.

    The problem is that your Emacs is not finding the version of IDLWAVE you installed. Emacs might come with an older bundled copy of IDLWAVE which is likely what’s being used instead. You need to make sure your Emacs load-path contains the directory where IDLWAVE is installed (/usr/local/share/emacs/site-lisp, by default), before Emacs’s default search directories. You can accomplish this by putting the following in your .emacs:

    (setq load-path (cons "/usr/local/share/emacs/site-lisp" load-path))

    You can check on your load-path value using C-h v load-path RET, and C-h m in an IDLWAVE buffer should show you the version Emacs is using.

  9. IDLWAVE is screwing up the formatting of my .idl files.

    Actually, this isn’t IDLWAVE at all, but ‘idl-mode’, an unrelated programming mode for CORBA’s Interface Definition Language (you should see ‘(IDL)’, not ‘(IDLWAVE)’ in the mode-line). One solution: don’t name your file .idl, but rather .pro. Another solution: make sure .idl files load IDLWAVE instead of ‘idl-mode’ by adding the following to your .emacs:

    (setcdr (rassoc 'idl-mode auto-mode-alist) 'idlwave-mode)
  10. The routine info for my local routines is out of date!

    IDLWAVE collects routine info from various locations (see Routine Information Sources). Routines in files visited in a buffer or compiled in the shell should be up to date. For other routines, the information is only as current as the most recent scan. If you have a rapidly changing set of routines, and you’d like the latest routine information to be available for it, one powerful technique is to make use of the library catalog tool, ‘idlwave_catalog’. Simply add a line to your ‘cron’ file (‘crontab -e’ will let you edit this on some systems), like this

    45 3 * * 1-5 (cd /path/to/myidllib; /path/to/idlwave_catalog MyLib)

    where ‘MyLib’ is the name of your library. This will rescan all .pro files at or below /path/to/myidllib every week night at 3:45am. You can even scan site-wide libraries with this method, and the most recent information will be available to all users. Since the scanning is very fast, there is very little impact.

  11. All the Greek-font characters in the HTML help are displayed as Latin characters!

    Unfortunately, the HTMLHelp files RSI provides attempt to switch to ‘Symbol’ font to display Greek characters, which is not really an permitted method for doing this in HTML. There is a "workaround" for some browsers: See HTML Help Browser Tips.

  12. In the shell, my long commands are truncated at 256 characters!

    This actually happens when running IDL in an XTerm as well. There are a couple of workarounds: define_key,/control,'^d' (e.g., in your $IDL_STARTUP file) will disable the ‘EOF’ character and give you a 512 character limit. You won’t be able to use C-d to quit the shell, however. Another possibility is !EDIT_INPUT=0, which gives you an infinite limit (OK, a memory-bounded limit), but disables the processing of background widget events (those with /NO_BLOCK passed to XManager).

  13. When I invoke IDL HTML help on a routine, the page which is loaded is one page off, e.g., for CONVERT_COORD, I get CONTOUR.

    You have a mismatch between your help index and the HTML help package you downloaded. You need to ensure you download a “downgrade kit” if you are using anything older than the latest HTML help package. A new help package appears with each IDL release (assuming the documentation is updated). See the maintainers webpage for more. Note that, starting with IDL 6.2, the HTML help and its catalog are distributed with IDL, and so should never be inconsistent.

Next: , Previous: , Up: IDLWAVE   [Contents][Index]

Appendix F GNU Free Documentation License

Version 1.2, November 2002
Copyright (C) 2000,2001,2002  Free Software Foundation, Inc.
51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.


    The purpose of this License is to make a manual, textbook, or other functional and useful document “free” in the sense of freedom: to assure everyone the effective freedom to copy and redistribute it, with or without modifying it, either commercially or noncommercially. Secondarily, this License preserves for the author and publisher a way to get credit for their work, while not being considered responsible for modifications made by others.

    This License is a kind of “copyleft,” which means that derivative works of the document must themselves be free in the same sense. It complements the GNU General Public License, which is a copyleft license designed for free software.

    We have designed this License in order to use it for manuals for free software, because free software needs free documentation: a free program should come with manuals providing the same freedoms that the software does. But this License is not limited to software manuals; it can be used for any textual work, regardless of subject matter or whether it is published as a printed book. We recommend this License principally for works whose purpose is instruction or reference.


    This License applies to any manual or other work, in any medium, that contains a notice placed by the copyright holder saying it can be distributed under the terms of this License. Such a notice grants a world-wide, royalty-free license, unlimited in duration, to use that work under the conditions stated herein. The “Document,” below, refers to any such manual or work. Any member of the public is a licensee, and is addressed as “you.” You accept the license if you copy, modify or distribute the work in a way requiring permission under copyright law.

    A “Modified Version” of the Document means any work containing the Document or a portion of it, either copied verbatim, or with modifications and/or translated into another language.

    A “Secondary Section” is a named appendix or a front-matter section of the Document that deals exclusively with the relationship of the publishers or authors of the Document to the Document’s overall subject (or to related matters) and contains nothing that could fall directly within that overall subject. (Thus, if the Document is in part a textbook of mathematics, a Secondary Section may not explain any mathematics.) The relationship could be a matter of historical connection with the subject or with related matters, or of legal, commercial, philosophical, ethical or political position regarding them.

    The “Invariant Sections” are certain Secondary Sections whose titles are designated, as being those of Invariant Sections, in the notice that says that the Document is released under this License. If a section does not fit the above definition of Secondary then it is not allowed to be designated as Invariant. The Document may contain zero Invariant Sections. If the Document does not identify any Invariant Sections then there are none.

    The “Cover Texts” are certain short passages of text that are listed, as Front-Cover Texts or Back-Cover Texts, in the notice that says that the Document is released under this License. A Front-Cover Text may be at most 5 words, and a Back-Cover Text may be at most 25 words.

    A “Transparent” copy of the Document means a machine-readable copy, represented in a format whose specification is available to the general public, that is suitable for revising the document straightforwardly with generic text editors or (for images composed of pixels) generic paint programs or (for drawings) some widely available drawing editor, and that is suitable for input to text formatters or for automatic translation to a variety of formats suitable for input to text formatters. A copy made in an otherwise Transparent file format whose markup, or absence of markup, has been arranged to thwart or discourage subsequent modification by readers is not Transparent. An image format is not Transparent if used for any substantial amount of text. A copy that is not “Transparent” is called “Opaque.”

    Examples of suitable formats for Transparent copies include plain ASCII without markup, Texinfo input format, LaTeX input format, SGML or XML using a publicly available DTD, and standard-conforming simple HTML, PostScript or PDF designed for human modification. Examples of transparent image formats include PNG, XCF and JPG. Opaque formats include proprietary formats that can be read and edited only by proprietary word processors, SGML or XML for which the DTD and/or processing tools are not generally available, and the machine-generated HTML, PostScript or PDF produced by some word processors for output purposes only.

    The “Title Page” means, for a printed book, the title page itself, plus such following pages as are needed to hold, legibly, the material this License requires to appear in the title page. For works in formats which do not have any title page as such, “Title Page” means the text near the most prominent appearance of the work’s title, preceding the beginning of the body of the text.

    A section “Entitled XYZ” means a named subunit of the Document whose title either is precisely XYZ or contains XYZ in parentheses following text that translates XYZ in another language. (Here XYZ stands for a specific section name mentioned below, such as “Acknowledgements,” “Dedications,” “Endorsements,” or “History.”) To “Preserve the Title” of such a section when you modify the Document means that it remains a section “Entitled XYZ” according to this definition.

    The Document may include Warranty Disclaimers next to the notice which states that this License applies to the Document. These Warranty Disclaimers are considered to be included by reference in this License, but only as regards disclaiming warranties: any other implication that these Warranty Disclaimers may have is void and has no effect on the meaning of this License.


    You may copy and distribute the Document in any medium, either commercially or noncommercially, provided that this License, the copyright notices, and the license notice saying this License applies to the Document are reproduced in all copies, and that you add no other conditions whatsoever to those of this License. You may not use technical measures to obstruct or control the reading or further copying of the copies you make or distribute. However, you may accept compensation in exchange for copies. If you distribute a large enough number of copies you must also follow the conditions in section 3.

    You may also lend copies, under the same conditions stated above, and you may publicly display copies.


    If you publish printed copies (or copies in media that commonly have printed covers) of the Document, numbering more than 100, and the Document’s license notice requires Cover Texts, you must enclose the copies in covers that carry, clearly and legibly, all these Cover Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on the back cover. Both covers must also clearly and legibly identify you as the publisher of these copies. The front cover must present the full title with all words of the title equally prominent and visible. You may add other material on the covers in addition. Copying with changes limited to the covers, as long as they preserve the title of the Document and satisfy these conditions, can be treated as verbatim copying in other respects.

    If the required texts for either cover are too voluminous to fit legibly, you should put the first ones listed (as many as fit reasonably) on the actual cover, and continue the rest onto adjacent pages.

    If you publish or distribute Opaque copies of the Document numbering more than 100, you must either include a machine-readable Transparent copy along with each Opaque copy, or state in or with each Opaque copy a computer-network location from which the general network-using public has access to download using public-standard network protocols a complete Transparent copy of the Document, free of added material. If you use the latter option, you must take reasonably prudent steps, when you begin distribution of Opaque copies in quantity, to ensure that this Transparent copy will remain thus accessible at the stated location until at least one year after the last time you distribute an Opaque copy (directly or through your agents or retailers) of that edition to the public.

    It is requested, but not required, that you contact the authors of the Document well before redistributing any large number of copies, to give them a chance to provide you with an updated version of the Document.


    You may copy and distribute a Modified Version of the Document under the conditions of sections 2 and 3 above, provided that you release the Modified Version under precisely this License, with the Modified Version filling the role of the Document, thus licensing distribution and modification of the Modified Version to whoever possesses a copy of it. In addition, you must do these things in the Modified Version:

    A. Use in the Title Page (and on the covers, if any) a title distinct from that of the Document, and from those of previous versions (which should, if there were any, be listed in the History section of the Document). You may use the same title as a previous version if the original publisher of that version gives permission.
    B. List on the Title Page, as authors, one or more persons or entities responsible for authorship of the modifications in the Modified Version, together with at least five of the principal authors of the Document (all of its principal authors, if it has fewer than five), unless they release you from this requirement.
    C. State on the Title page the name of the publisher of the Modified Version, as the publisher.
    D. Preserve all the copyright notices of the Document.
    E. Add an appropriate copyright notice for your modifications adjacent to the other copyright notices.
    F. Include, immediately after the copyright notices, a license notice giving the public permission to use the Modified Version under the terms of this License, in the form shown in the Addendum below.
    G. Preserve in that license notice the full lists of Invariant Sections and required Cover Texts given in the Document’s license notice.
    H. Include an unaltered copy of this License.
    I. Preserve the section Entitled “History,” Preserve its Title, and add to it an item stating at least the title, year, new authors, and publisher of the Modified Version as given on the Title Page. If there is no section Entitled “History” in the Document, create one stating the title, year, authors, and publisher of the Document as given on its Title Page, then add an item describing the Modified Version as stated in the previous sentence.
    J. Preserve the network location, if any, given in the Document for public access to a Transparent copy of the Document, and likewise the network locations given in the Document for previous versions it was based on. These may be placed in the “History” section. You may omit a network location for a work that was published at least four years before the Document itself, or if the original publisher of the version it refers to gives permission.
    K. For any section Entitled “Acknowledgements” or “Dedications,” Preserve the Title of the section, and preserve in the section all the substance and tone of each of the contributor acknowledgements and/or dedications given therein.
    L. Preserve all the Invariant Sections of the Document, unaltered in their text and in their titles. Section numbers or the equivalent are not considered part of the section titles.
    M. Delete any section Entitled “Endorsements.” Such a section may not be included in the Modified Version.
    N. Do not retitle any existing section to be Entitled “Endorsements” or to conflict in title with any Invariant Section.
    O. Preserve any Warranty Disclaimers.

    If the Modified Version includes new front-matter sections or appendices that qualify as Secondary Sections and contain no material copied from the Document, you may at your option designate some or all of these sections as invariant. To do this, add their titles to the list of Invariant Sections in the Modified Version’s license notice. These titles must be distinct from any other section titles.

    You may add a section Entitled “Endorsements,” provided it contains nothing but endorsements of your Modified Version by various parties–for example, statements of peer review or that the text has been approved by an organization as the authoritative definition of a standard.

    You may add a passage of up to five words as a Front-Cover Text, and a passage of up to 25 words as a Back-Cover Text, to the end of the list of Cover Texts in the Modified Version. Only one passage of Front-Cover Text and one of Back-Cover Text may be added by (or through arrangements made by) any one entity. If the Document already includes a cover text for the same cover, previously added by you or by arrangement made by the same entity you are acting on behalf of, you may not add another; but you may replace the old one, on explicit permission from the previous publisher that added the old one.

    The author(s) and publisher(s) of the Document do not by this License give permission to use their names for publicity for or to assert or imply endorsement of any Modified Version.


    You may combine the Document with other documents released under this License, under the terms defined in section 4 above for modified versions, provided that you include in the combination all of the Invariant Sections of all of the original documents, unmodified, and list them all as Invariant Sections of your combined work in its license notice, and that you preserve all their Warranty Disclaimers.

    The combined work need only contain one copy of this License, and multiple identical Invariant Sections may be replaced with a single copy. If there are multiple Invariant Sections with the same name but different contents, make the title of each such section unique by adding at the end of it, in parentheses, the name of the original author or publisher of that section if known, or else a unique number. Make the same adjustment to the section titles in the list of Invariant Sections in the license notice of the combined work.

    In the combination, you must combine any sections Entitled “History” in the various original documents, forming one section Entitled “History”; likewise combine any sections Entitled “Acknowledgements,” and any sections Entitled “Dedications.” You must delete all sections Entitled “Endorsements.”


    You may make a collection consisting of the Document and other documents released under this License, and replace the individual copies of this License in the various documents with a single copy that is included in the collection, provided that you follow the rules of this License for verbatim copying of each of the documents in all other respects.

    You may extract a single document from such a collection, and distribute it individually under this License, provided you insert a copy of this License into the extracted document, and follow this License in all other respects regarding verbatim copying of that document.


    A compilation of the Document or its derivatives with other separate and independent documents or works, in or on a volume of a storage or distribution medium, is called an “aggregate” if the copyright resulting from the compilation is not used to limit the legal rights of the compilation’s users beyond what the individual works permit. When the Document is included in an aggregate, this License does not apply to the other works in the aggregate which are not themselves derivative works of the Document.

    If the Cover Text requirement of section 3 is applicable to these copies of the Document, then if the Document is less than one half of the entire aggregate, the Document’s Cover Texts may be placed on covers that bracket the Document within the aggregate, or the electronic equivalent of covers if the Document is in electronic form. Otherwise they must appear on printed covers that bracket the whole aggregate.


    Translation is considered a kind of modification, so you may distribute translations of the Document under the terms of section 4. Replacing Invariant Sections with translations requires special permission from their copyright holders, but you may include translations of some or all Invariant Sections in addition to the original versions of these Invariant Sections. You may include a translation of this License, and all the license notices in the Document, and any Warranty Disclaimers, provided that you also include the original English version of this License and the original versions of those notices and disclaimers. In case of a disagreement between the translation and the original version of this License or a notice or disclaimer, the original version will prevail.

    If a section in the Document is Entitled “Acknowledgements,” “Dedications,” or “History,” the requirement (section 4) to Preserve its Title (section 1) will typically require changing the actual title.


    You may not copy, modify, sublicense, or distribute the Document except as expressly provided for under this License. Any other attempt to copy, modify, sublicense or distribute the Document is void, and will automatically terminate your rights under this License. However, parties who have received copies, or rights, from you under this License will not have their licenses terminated so long as such parties remain in full compliance.


    The Free Software Foundation may publish new, revised versions of the GNU Free Documentation License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns. See

    Each version of the License is given a distinguishing version number. If the Document specifies that a particular numbered version of this License “or any later version” applies to it, you have the option of following the terms and conditions either of that specified version or of any later version that has been published (not as a draft) by the Free Software Foundation. If the Document does not specify a version number of this License, you may choose any version ever published (not as a draft) by the Free Software Foundation.

ADDENDUM: How to use this License for your documents

To use this License in a document you have written, include a copy of the License in the document and put the following copyright and license notices just after the title page:

Copyright (C)  year  your name.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.2
or any later version published by the Free Software Foundation;
with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
A copy of the license is included in the section entitled ``GNU
Free Documentation License.''

If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts, replace the “with...Texts.” line with this:

with the Invariant Sections being list their titles, with the
Front-Cover Texts being list, and with the Back-Cover Texts being

If you have Invariant Sections without Cover Texts, or some other combination of the three, merge those two alternatives to suit the situation.

If your document contains nontrivial examples of program code, we recommend releasing these examples in parallel under your choice of free software license, such as the GNU General Public License, to permit their use in free software.


Jump to:   !   *   -   .  
A   B   C   D   E   F   G   H   I   K   L   M   N   O   P   Q   R   S   T   U   W   X  
Index Entry  Section

!DIR, IDL variable: Routine Info
!DIR, IDL variable: User Catalog
!DIR, IDL variable: Load-Path Shadows
!PATH, IDL variable: Routine Info
!PATH, IDL variable: Routine Definitions

*Debugging*: Electric Debug Mode

->: Object Method Completion and Class Ambiguity

.emacs: Configuration Examples
.idlwave_catalog: Library Catalogs

Abbreviations: Abbreviations
Acknowledgments: Acknowledgments
Actions: Actions
Actions, applied to foreign code: Actions
Active text, in routine info: Routine Info
Application, testing for shadowing: Load-Path Shadows
Authors, of IDLWAVE: Acknowledgments
auto-fill-mode: Continuation Lines

Block boundary check: Block Boundary Check
Block, closing: Block Boundary Check
Breakpoints: Breakpoints and Stepping
Browser Tips: HTML Help Browser Tips
Buffer, testing for shadowing: Load-Path Shadows
Buffers, killing: Routine Source
Buffers, scanning for routine info: Routine Info
Buffers, scanning for routine info: Routine Information Sources
Builtin list of routines: Routine Information Sources

C-c ?: Routine Info
C-c C-d: Debug Key Bindings
C-c C-d C-b: Breakpoints and Stepping
C-c C-d C-b: Breakpoints and Stepping
C-c C-d C-c: Compiling Programs
C-c C-d C-e: Compiling Programs
C-c C-d C-p: Examining Variables
C-c C-h: Doc Header
C-c C-i: Routine Info
C-c C-i: Completion
C-c C-m: Doc Header
C-c C-s: Starting the Shell
C-c C-v: Routine Source
C-M-\: Code Indentation
Calling sequences: Routine Info
Calling stack, walking: Walking the Calling Stack
CALL_EXTERNAL, IDL routine: Routine Definitions
Canceling completion: Completion
Case changes: Case Changes
Case of completed words: Case of Completed Words
Catalogs: Catalogs
Categories, of routines: Routine Info
cc-mode.el: Introduction
Changelog, in doc header.: Doc Header
Character input mode (Shell): Using the Shell
Class ambiguity: Object Method Completion and Class Ambiguity
Class name completion: Completion
Class query, forcing: Object Method Completion and Class Ambiguity
Class tags, in online help: Help with Source
Closing a block: Block Boundary Check
Code formatting: Code Formatting
Code indentation: Code Indentation
Code structure, moving through: Motion Commands
Code templates: Code Templates
Coding standards, enforcing: Actions
Comint: Using the Shell
Comint, Emacs package: The IDLWAVE Shell
Commands in shell, showing: Commands Sent to the Shell
Commands, multi-line: Multi-Line Commands
Comment indentation: Comment Indentation
Compiling library modules: Resolving Routines
Compiling programs: Compiling Programs
Compiling regions: Compiling Programs
Completion: Completion
Completion, ambiguity: Completion
Completion, canceling: Completion
Completion, forcing function name: Completion
Completion, in the shell: Using the Shell
Completion, Online Help: Completion
Completion, scrolling: Completion
Completion, structure tag: Structure Tag Completion
Configuration examples: Configuration Examples
Context, for online help: Online Help
Continuation lines: Continuation Lines
Continued statement indentation: Continued Statement Indentation
Contributors, to IDLWAVE: Acknowledgments
Copyright, of IDLWAVE: Top
CORBA (Common Object Request Broker Architecture): Introduction
Custom expression examination: Custom Expression Examination

Debugging: Debugging IDL Programs
Debugging Interface: A Tale of Two Modes
Dedicated frame, for shell buffer: Starting the Shell
Default command line, executing: Compiling Programs
Default routine, for info and help: Routine Info
Default settings, of options: Configuration Examples
DocLib header: Doc Header
DocLib header, as online help: Help with Source
Documentation header: Doc Header
Downcase, enforcing for reserved words: Case Changes
Duplicate routines: Routine Info
Duplicate routines: Load-Path Shadows

Eclipse-based help: Online Help
Electric Debug Mode: A Tale of Two Modes
Electric Debug Mode: Electric Debug Mode
Emacs, distributed with IDLWAVE: Installing IDLWAVE
Email address, of Maintainer: Acknowledgments
END type checking: Block Boundary Check
END, automatic insertion: Block Boundary Check
END, expanding: Block Boundary Check
ENVI: Starting the Shell
Examining expressions: Examining Variables
Example configuration: Configuration Examples
Executing a default command line: Compiling Programs
Execution, controlled: Breakpoints and Stepping
Expressions, custom examination: Custom Expression Examination
Expressions, printing & help: Examining Variables
External routines: Routine Definitions

Feature overview: Introduction
Filling: Continuation Lines
Flags, in routine info: Routine Info
Font lock: Syntax Highlighting
Forcing class query.: Object Method Completion and Class Ambiguity
Foreign code, adapting: Code Indentation
Foreign code, adapting: Actions
Formatting, of code: Code Formatting
Frame, for shell buffer: Starting the Shell
FTP site: Installing IDLWAVE
Function definitions, jumping to: Motion Commands
Function name completion: Completion

Getting Started: Getting Started
get_html_rinfo: Documentation Scan

Hanging paragraphs: Comment Indentation
Hanging paragraphs: Continuation Lines
Header, for file documentation: Doc Header
Help using HTML manuals: Help with HTML Documentation
Help using routine source: Help with Source
HELP, on expressions: Examining Variables
Highlighting of syntax: Syntax Highlighting
Highlighting of syntax, Octals: Octals and Highlighting
History, shell: Using the Shell
Homepage for IDLWAVE: Installing IDLWAVE
Hooks: Misc Options
Hooks: Starting the Shell
HTML Help: Help with HTML Documentation

IDL Assistant: Help with HTML Documentation
IDL library routine info: User Catalog
IDL manual, HTML version: Help with HTML Documentation
IDL variable !DIR: Routine Info
IDL variable !DIR: User Catalog
IDL variable !DIR: Load-Path Shadows
IDL variable !PATH: Routine Info
IDL variable !PATH: Routine Definitions
IDL, as Emacs subprocess: The IDLWAVE Shell
idl-shell.el: Introduction
idl.el: Introduction
IDL> Prompt: Starting the Shell
idlw-help.el: Online Help
idlw-help.txt: Online Help
idlw-rinfo.el: Documentation Scan
IDLWAVE in a Nutshell: IDLWAVE in a Nutshell
IDLWAVE major mode: The IDLWAVE Major Mode
IDLWAVE shell: The IDLWAVE Shell
IDLWAVE, homepage: Installing IDLWAVE
idlwave-abbrev-change-case: Case Changes
idlwave-abbrev-move: Abbreviations
idlwave-abbrev-start-char: Abbreviations
idlwave-auto-fill-split-string: Continuation Lines
idlwave-auto-routine-info-updates: Routine Information Sources
idlwave-auto-write-path: Catalogs
idlwave-begin-line-comment: Comment Indentation
idlwave-block-indent: Code Indentation
idlwave-class-arrow-face: Object Method Completion and Class Ambiguity
idlwave-code-comment: Comment Indentation
idlwave-complete-empty-string-as-lower-case: Case of Completed Words
idlwave-complete-structure-tags: Structure Tag Completion
idlwave-completion-case: Case of Completed Words
idlwave-completion-fontify-classes: Object Method Completion and Class Ambiguity
idlwave-completion-force-default-case: Case of Completed Words
idlwave-completion-restore-window-configuration: Completion
idlwave-completion-show-classes: Object Method Completion and Class Ambiguity
idlwave-config-directory: Catalogs
idlwave-continuation-indent: Continued Statement Indentation
idlwave-default-font-lock-items: Syntax Highlighting
idlwave-do-actions: Actions
idlwave-doc-modifications-keyword: Doc Header
idlwave-doclib-end: Doc Header
idlwave-doclib-start: Doc Header
idlwave-end-offset: Code Indentation
idlwave-expand-generic-end: Block Boundary Check
idlwave-extra-help-function: Help with Source
idlwave-file-header: Doc Header
idlwave-fill-comment-line-only: Continuation Lines
idlwave-function-completion-adds-paren: Completion
idlwave-hang-indent-regexp: Continuation Lines
idlwave-hanging-indent: Continuation Lines
idlwave-header-to-beginning-of-file: Doc Header
idlwave-help-application: Misc Options
idlwave-help-browser-function: Help with HTML Documentation
idlwave-help-browser-is-local: Help with HTML Documentation
idlwave-help-doclib-keyword: Help with Source
idlwave-help-doclib-name: Help with Source
idlwave-help-fontify-source-code: Help with Source
idlwave-help-frame-parameters: Help with Source
idlwave-help-link-face: Help with HTML Documentation
idlwave-help-source-try-header: Help with Source
idlwave-help-use-assistant: Help with HTML Documentation
idlwave-help-use-dedicated-frame: Help with Source
idlwave-highlight-help-links-in-completion: Completion
idlwave-html-help-location: Help with HTML Documentation
idlwave-html-system-help-location: Help with HTML Documentation
idlwave-indent-to-open-paren: Continued Statement Indentation
idlwave-init-rinfo-when-idle-after: Routine Information Sources
idlwave-keyword-class-inheritance: Class and Keyword Inheritance
idlwave-keyword-completion-adds-equal: Completion
idlwave-library-path: Catalogs
idlwave-main-block-indent: Code Indentation
idlwave-max-extra-continuation-indent: Continued Statement Indentation
idlwave-max-popup-menu-items: Help with Source
idlwave-mode-hook: Misc Options
idlwave-no-change-comment: Comment Indentation
idlwave-pad-keyword: Padding Operators
idlwave-query-class: Object Method Completion and Class Ambiguity
idlwave-query-shell-for-routine-info: Routine Information Sources
idlwave-reindent-end: Block Boundary Check
idlwave-reserved-word-upcase: Case Changes
idlwave-resize-routine-help-window: Routine Info
idlwave-rinfo-max-source-lines: Routine Info
idlwave-scan-all-buffers-for-routine-info: Routine Information Sources
idlwave-shell-activate-prefix-keybindings: Debug Key Bindings
idlwave-shell-arrows-do-history: Using the Shell
idlwave-shell-automatic-electric-debug: Electric Debug Mode
idlwave-shell-automatic-start: Starting the Shell
idlwave-shell-breakpoint-face: Breakpoints and Stepping
idlwave-shell-breakpoint-popup-menu: Breakpoints and Stepping
idlwave-shell-buffer-height-frac: Starting the Shell
idlwave-shell-comint-settings: Using the Shell
idlwave-shell-command-history-file: Starting the Shell
idlwave-shell-command-line-options: Starting the Shell
idlwave-shell-debug-modifiers: Debug Key Bindings
idlwave-shell-electric-stop-color: Electric Debug Mode
idlwave-shell-electric-stop-line-face: Electric Debug Mode
idlwave-shell-electric-zap-to-file: Electric Debug Mode
idlwave-shell-examine-alist: Custom Expression Examination
idlwave-shell-explicit-file-name: Starting the Shell
idlwave-shell-expression-face: Examining Variables
idlwave-shell-file-name-chars: Using the Shell
idlwave-shell-frame-parameters: Starting the Shell
idlwave-shell-graphics-window-size: Using the Shell
idlwave-shell-initial-commands: Starting the Shell
idlwave-shell-input-mode-spells: Using the Shell
idlwave-shell-mark-breakpoints: Breakpoints and Stepping
idlwave-shell-mark-stop-line: Breakpoints and Stepping
idlwave-shell-max-print-length: Examining Variables
idlwave-shell-mode-hook: Starting the Shell
idlwave-shell-output-face: Examining Variables
idlwave-shell-overlay-arrow: Breakpoints and Stepping
idlwave-shell-prefix-key: Debug Key Bindings
idlwave-shell-process-name: Starting the Shell
idlwave-shell-prompt-pattern: Starting the Shell
idlwave-shell-raise-frame: Starting the Shell
idlwave-shell-save-command-history: Starting the Shell
idlwave-shell-separate-examine-output: Examining Variables
idlwave-shell-show-commands: Commands Sent to the Shell
idlwave-shell-stop-line-face: Breakpoints and Stepping
idlwave-shell-temp-pro-prefix: Starting the Shell
idlwave-shell-use-dedicated-frame: Starting the Shell
idlwave-shell-use-dedicated-window: Starting the Shell
idlwave-shell-use-input-mode-magic: Using the Shell
idlwave-shell-use-toolbar: Debugging IDL Programs
idlwave-show-block: Block Boundary Check
idlwave-special-lib-alist: Routine Info
idlwave-special-lib-alist: User Catalog
idlwave-split-line-string: Continuation Lines
idlwave-startup-message: Misc Options
idlwave-store-inquired-class: Object Method Completion and Class Ambiguity
idlwave-support-inheritance: Class and Keyword Inheritance
idlwave-surround-by-blank: Padding Operators
idlwave-system-directory: Catalogs
idlwave-timestamp-hook: Doc Header
idlwave-use-last-hang-indent: Continuation Lines
idlwave-use-library-catalogs: Library Catalogs
idlwave_catalog: Library Catalogs
Imenu: Motion Commands
Indentation: Code Indentation
Indentation, continued statement: Continued Statement Indentation
Indentation, of foreign code: Code Indentation
Inheritance, class: Class and Keyword Inheritance
Inheritance, keyword: Class and Keyword Inheritance
Input mode: Using the Shell
Inserting keywords, from routine info: Routine Info
Installation: Installation
Installing online help: Online Help
Installing online help: Installing Online Help
Interactive Data Language: Introduction
Interface Definition Language: Introduction
Interview, with the maintainer: Configuration Examples
Introduction: Introduction

Key bindings: Debug Key Bindings
Key bindings for debugging: Debugging IDL Programs
Keyword completion: Completion
Keyword inheritance: Class and Keyword Inheritance
Keywords of a routine: Routine Info
Killing autoloaded buffers: Routine Source

Library catalogs: Library Catalogs
Line input mode (Shell): Using the Shell
Line splitting: Continuation Lines
LINKIMAGE, IDL routine: Routine Definitions
Load-path shadows: Routine Info
Load-path shadows: Load-Path Shadows

M-?: Online Help
M-q: Continuation Lines
M-RET: Continuation Lines
M-TAB: Completion
macOS: The IDLWAVE Shell
macOS: User Catalog
macOS: Windows and macOS
Magic spells, for input mode: Using the Shell
Maintainer, of IDLWAVE: Acknowledgments
Major mode, idlwave-mode: The IDLWAVE Major Mode
Major mode, idlwave-shell-mode: The IDLWAVE Shell
Method completion: Completion
Method Completion in Shell: Object Method Completion in the Shell
Mixed case completion: Case of Completed Words
Modification timestamp: Doc Header
Module source file: Routine Source
Motion commands: Motion Commands
Mouse binding to print expressions: Examining Variables
Multi-line commands: Multi-Line Commands
Multiply defined routines: Routine Info
Multiply defined routines: Load-Path Shadows

Nutshell, IDLWAVE in a: IDLWAVE in a Nutshell

Object method completion: Completion
Object methods: Object Method Completion and Class Ambiguity
OBJ_NEW, special online help: Online Help
Online Help: Online Help
Online Help from the routine info buffer: Routine Info
Online Help in *Completions* buffer: Completion
Online Help, in the shell: Using the Shell
Online Help, Installation: Online Help
Online Help, Installation: Installing Online Help
Operators, padding with spaces: Padding Operators

Padding operators with spaces: Padding Operators
Paragraphs, filling: Comment Indentation
Paragraphs, hanging: Comment Indentation
Perl program, to create idlw-rinfo.el: Documentation Scan
PRINT expressions: Examining Variables
Printing expressions: Examining Variables
Printing expressions, on calling stack: Examining Variables
Procedure definitions, jumping to: Motion Commands
Procedure name completion: Completion
Program structure, moving through: Motion Commands
Programs, compiling: Compiling Programs

Quick-Start: Getting Started

RESOLVE_ROUTINE: Resolving Routines
Restrictions for expression printing: Examining Variables
Routine definitions: Routine Definitions
Routine definitions, multiple: Routine Info
Routine definitions, multiple: Load-Path Shadows
Routine info: Routine Info
Routine info sources: Routine Information Sources
Routine info, in the shell: Using the Shell
Routine source file: Routine Source
Routine source information: Routine Info
Routines, resolving: Resolving Routines
ROUTINE_NAMES, IDL procedure: Examining Variables

Saving object class on ->: Object Method Completion and Class Ambiguity
Scanning buffers for routine info: Routine Info
Scanning buffers for routine info: Routine Information Sources
Scanning the documentation: Documentation Scan
Scrolling the *Completions* window: Completion
self object, default class: Object Method Completion and Class Ambiguity
Shadows, load-path: Routine Info
Shadows, load-path: Load-Path Shadows
Shell, basic commands: Using the Shell
Shell, querying for routine info: Routine Info
Shell, querying for routine info: Routine Information Sources
Shell, starting: Starting the Shell
Showing commands in shell: Commands Sent to the Shell
Source code, as online help: Help with Source
Source file, access from routine info: Routine Info
Source file, of a routine: Routine Source
Sources of routine information: Sources of Routine Info
Space, around operators: Padding Operators
Speed, of online help: Online Help
Speedbar, Emacs package: Motion Commands
Spells, magic: Using the Shell
Splitting, of lines: Continuation Lines
Starting the shell: Starting the Shell
Stepping: Breakpoints and Stepping
String splitting: Continuation Lines
Structure tag completion: Structure Tag Completion
Structure tags, in online help: Help with Source
Subprocess of Emacs, IDL: The IDLWAVE Shell
Subprocess of Emacs, IDL: Starting the Shell
Summary of important commands: IDLWAVE in a Nutshell
Syntax highlighting: Syntax Highlighting
Syntax highlighting, Octals: Octals and Highlighting

Templates: Code Templates
Thanks: Acknowledgments
Timestamp, in doc header.: Doc Header
Toolbar: Debugging IDL Programs
Troubleshooting: Troubleshooting
Tutorial: Getting Started

Upcase, enforcing for reserved words: Case Changes
Updating routine info: Routine Info
Updating routine info: Routine Information Sources
URL, homepage for IDLWAVE: Installing IDLWAVE
User catalog: User Catalog

Windows: The IDLWAVE Shell
Windows: User Catalog
Windows: Load-Path Shadows
Windows: Windows and macOS

XEmacs package IDLWAVE: Installing IDLWAVE
XML Help Catalog: Online Help

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IDL is a registered trademark ITT Visual Information Solutions


IDLWAVE can also be used for editing source files for the related WAVE/CL language, but with only limited support.


This list is created by scanning the IDL manuals and might contain (very few) errors. Please report any errors to the maintainer, so that they can be fixed.


This is different from normal Emacs/Comint behavior, but more like an xterm. If you prefer the default comint functionality, check the variable idlwave-shell-arrows-do-history.


Note that this binding is not symmetric: C-c C-d C-q is bound to idlwave-shell-quit, which quits your IDL session.


Available as p and ? in Electric Debug Mode (see Electric Debug Mode)


In Electric Debug Mode (see Electric Debug Mode), the key x provides a single-character shortcut interface to the same examine functions for the expression at point or marked by the region.


The initial ‘+’ leads to recursive expansion of the path, just like in IDL


Unix systems only, I think.