idlwave.texi

\input texinfo  @c -*-texinfo-*-
@c %**start of header
@setfilename idlwave
@settitle IDLWAVE User Manual
@dircategory Emacs
@direntry
* IDLWAVE: (idlwave).	Major mode and shell for IDL files.
@end direntry
@synindex ky cp
@syncodeindex vr cp
@syncodeindex fn cp
@set VERSION 6.2
@set EDITION 6.2
@set IDLVERSION 6.4
@set NSYSROUTINES 4346
@set DATE November, 2007
@set AUTHOR J.D. Smith & Carsten Dominik
@set MAINTAINER J.D. Smith
@set IDLWAVEHOMEPAGE http://idlwave.org/
@c %**end of header
@finalout

@ifinfo 
This file documents IDLWAVE, a major mode for editing IDL files with
Emacs, and interacting with an IDL shell run as a subprocess.

This is edition @value{EDITION} of the IDLWAVE User Manual for IDLWAVE
@value{VERSION}

Copyright @copyright{} 1999, 2000, 2001, 2002, 2003, 2004, 2005, 
          2006, 2007 Free Software Foundation, Inc.

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, with the Front-Cover texts being ``A GNU
Manual'', and with the Back-Cover Texts as in (a) below.  A copy of the
license is included in the section entitled ``GNU Free Documentation
License'' in the Emacs manual.

(a) The FSF's Back-Cover Text is: ``You have freedom to copy and modify
this GNU Manual, like GNU software.  Copies published by the Free
Software Foundation raise funds for GNU development.''

This document is part of a collection distributed under the GNU Free
Documentation License.  If you want to distribute this document
separately from the collection, you can do so by adding a copy of the
license to the document, as described in section 6 of the license.
@end ifinfo

@titlepage
@title IDLWAVE User Manual
@subtitle Emacs major mode and shell for IDL
@subtitle Edition @value{EDITION}, @value{DATE}

@author by J.D. Smith & Carsten Dominik
@page
This is edition @value{EDITION} of the @cite{IDLWAVE User Manual} for
IDLWAVE version @value{VERSION}, @value{DATE}.
@sp 2
Copyright @copyright{} 1999, 2000, 2001, 2002, 2003, 2004, 2005, 
          2006, 2007 Free Software Foundation, Inc.
@sp 2
@cindex Copyright, of IDLWAVE
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, with the Front-Cover texts being ``A GNU
Manual'', and with the Back-Cover Texts as in (a) below.  A copy of the
license is included in the section entitled ``GNU Free Documentation
License'' in the Emacs manual.

(a) The FSF's Back-Cover Text is: ``You have freedom to copy and modify
this GNU Manual, like GNU software.  Copies published by the Free
Software Foundation raise funds for GNU development.''

This document is part of a collection distributed under the GNU Free
Documentation License.  If you want to distribute this document
separately from the collection, you can do so by adding a copy of the
license to the document, as described in section 6 of the license.
@end titlepage
@contents

@page

@ifnottex

@node Top, Introduction, (dir), (dir)

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

@end ifnottex

@menu
* Introduction::                What IDLWAVE is, and what it is not
* IDLWAVE in a Nutshell::       One page quick-start guide
* Getting Started::             Tutorial
* The IDLWAVE Major Mode::      The mode for editing IDL programs
* The IDLWAVE Shell::           
* Installation::                How to Install or Upgrade               
* Acknowledgements::            
* Sources of Routine Info::     How does IDLWAVE know about routine XYZ     
* HTML Help Browser Tips::      
* Configuration Examples::      The user is king
* Windows and MacOS::           What still works, and how
* Troubleshooting::             When good computers turn bad
* GNU Free Documentation License::  The license for this documentation.
* Index::                       Fast access

@detailmenu
 --- The Detailed Node Listing ---

Getting Started (Tutorial)

* Lesson I -- Development Cycle::  
* Lesson II -- Customization::  
* Lesson III -- User Catalog::  

The IDLWAVE Major Mode

* Code Formatting::             Making code look nice
* Routine Info::                Calling Sequence and Keyword List
* Online Help::                 One key press from source to help
* Completion::                  Completing routine names and Keywords
* Routine Source::              Finding routines, the easy way
* Resolving Routines::          Force the Shell to compile a routine
* Code Templates::              Frequent code constructs
* Abbreviations::               Abbreviations for common commands
* Actions::                     Changing case, Padding, End checking
* Doc Header::                  Inserting a standard header
* Motion Commands::             Moving through the structure of a program
* Misc Options::                Things that fit nowhere else

Code Formatting

* Code Indentation::            Reflecting the logical structure
* Continued Statement Indentation::  
* Comment Indentation::         Special indentation for comment lines
* Continuation Lines::          Splitting statements over lines
* Syntax Highlighting::         Font-lock support
* Octals and Highlighting::     Why "123 causes problems

Online Help

* Help with HTML Documentation::  
* Help with Source::            

Completion

* Case of Completed Words::     CaseOFcomPletedWords
* Object Method Completion and Class Ambiguity::  obj->Method, what?
* Object Method Completion in the Shell::  
* Class and Keyword Inheritance::  obj->Method, _EXTRA=e
* Structure Tag Completion::    Completing state.Tag

Actions

* Block Boundary Check::        Is the END statement correct?
* Padding Operators::           Enforcing space around `=' etc
* Case Changes::                Enforcing upper case keywords

The IDLWAVE Shell

* Starting the Shell::          How to launch IDL as a subprocess
* Using the Shell::             Interactively working with the Shell
* Multi-Line Commands::         
* Commands Sent to the Shell::  
* Debugging IDL Programs::      
* Examining Variables::         
* Custom Expression Examination::  

Debugging IDL Programs

* A Tale of Two Modes::         
* Debug Key Bindings::          
* Breakpoints and Stepping::    
* Compiling Programs::          
* Walking the Calling Stack::   
* Electric Debug Mode::         

Installation

* Installing IDLWAVE::          How to install the distribution
* Installing Online Help::      Where to get the additional files needed

Sources of Routine Info

* Routine Definitions::         Where IDL Routines are defined.
* Routine Information Sources::  So how does IDLWAVE know about...
* Catalogs::                    
* Load-Path Shadows::           Routines defined in several places
* Documentation Scan::          Scanning the IDL Manuals

Catalogs

* Library Catalogs::            
* User Catalog::                

@end detailmenu
@end menu

@node Introduction, IDLWAVE in a Nutshell, Top, Top
@chapter Introduction
@cindex Introduction
@cindex CORBA (Common Object Request Broker Architecture)
@cindex Interface Definition Language
@cindex Interactive Data Language
@cindex cc-mode.el
@cindex @file{idl.el}
@cindex @file{idl-shell.el}
@cindex Feature overview

IDLWAVE is a package which supports editing source files written in
the Interactive Data Language (IDL@footnote{IDL is a registered
trademark ITT Visual Information Solutions}
), and running IDL as an inferior shell@footnote{IDLWAVE can also be used
for editing source files for the related WAVE/CL language, but with only
limited support.}.  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 (@code{idlwave-mode}) and a mode for running the IDL
program as an inferior shell (@code{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:

@itemize @bullet
@item 
Smart code indentation and automatic-formatting.
@item
Three level syntax highlighting support.
@item 
Context-sensitive display of calling sequences and keywords for more
than 1000 native IDL routines, extendible to any additional number of
local routines, and already available with many pre-scanned libraries.
@item
Fast, context-sensitive online HTML help, or source-header help for
undocumented routines.
@item
Context sensitive completion of routine names, keywords, system
variables, class names and much more.
@item
Easy insertion of code templates and abbreviations of common constructs.
@item
Automatic corrections to enforce a variety of customizable coding
standards.
@item
Integrity checks and auto-termination of logical blocks.
@item
Routine name space conflict search with likelihood-of-use ranking.
@item
Support for @file{imenu} (Emacs) and @file{func-menu} (XEmacs).
@item
Documentation support.
@item
Running IDL as an inferior Shell with history search, command line
editing and all the completion and routine info capabilities present in
IDL source buffers.
@item
Full handling of debugging with breakpoints, with interactive setting
of break conditions, and easy stepping through code.
@item
Compilation, execution and interactive single-keystroke debugging of
programs directly from the source buffer.
@item
Quick, source-guided navigation of the calling stack, with variable
inspection, etc.
@item
Examining variables and expressions with a mouse click.
@item
And much, much more...
@end itemize

@ifnottex
@cindex Screenshots
Here are a number of screenshots showing IDLWAVE in action:

@itemize @bullet
@item
@uref{http://idlwave.org/screenshots/emacs_21_nav.gif,An IDLWAVE buffer}
@item
@uref{http://idlwave.org/screenshots/emacs_21_keys.gif,A keyword being completed}
@item
@uref{http://idlwave.org/screenshots/emacs_21_help.gif,Online help text.}
@item
@uref{http://idlwave.org/screenshots/emacs_21_ri.gif,Routine information displayed}
@item
@uref{http://idlwave.org/screenshots/emacs_21_bp.gif,Debugging code
stopped at a breakpoint}
@end itemize
@end ifnottex

IDLWAVE is the distant successor to the @file{idl.el} and
@file{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
@code{idl-mode}, defined in Emacs in the file @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 @kbd{C-h v}).  Some configuration examples are also given in the
appendix.

@node IDLWAVE in a Nutshell, Getting Started, Introduction, Top
@chapter IDLWAVE in a Nutshell
@cindex Summary of important commands
@cindex IDLWAVE in a Nutshell
@cindex Nutshell, IDLWAVE in a

@subheading Editing IDL Programs

@multitable @columnfractions .15 .85
@item @key{TAB}
@tab Indent the current line relative to context.
@item @kbd{C-M-\}
@tab Re-indent all lines in the current region.
@item @kbd{C-M-q}
@tab Re-indent all lines in the current routine.
@item @kbd{C-u @key{TAB}}
@tab Re-indent all lines in the current statement.
@item @kbd{M-@key{RET}}
@tab Start a continuation line, splitting the current line at point.
@item @kbd{M-;}
@tab Start new comment at line beginning or after code, or (un)comment
highlighted region.
@item @kbd{M-q}
@tab Fill the current comment paragraph.
@item @kbd{C-c ?}
@tab Display calling sequence and keywords for the procedure or function call
at point.
@item @kbd{M-?}
@tab Load context sensitive online help for nearby routine, keyword, etc.
@item @kbd{M-@key{TAB}}
@tab Complete a procedure name, function name or keyword in the buffer.
@item @kbd{C-c C-i}
@tab Update IDLWAVE's knowledge about functions and procedures.
@item @kbd{C-c C-v}
@tab Visit the source code of a procedure/function.
@item @kbd{C-u C-c C-v}
@tab Visit the source code of a procedure/function in this buffer.
@item @kbd{C-c C-h}
@tab Insert a standard documentation header.
@item @kbd{C-c @key{RET}}
@tab Insert a new timestamp and history item in the documentation header.
@end multitable

@subheading Running the IDLWAVE Shell, Debugging Programs

@multitable @columnfractions .15 .85
@item @kbd{C-c C-s}
@tab Start IDL as a subprocess and/or switch to the shell buffer.
@item @key{Up}, @kbd{M-p}
@tab Cycle back through IDL command history.
@item @key{Down},@kbd{M-n}
@tab Cycle forward.
@item @kbd{@key{TAB}}
@tab Complete a procedure name, function name or keyword in the shell buffer.
@item @kbd{C-c C-d C-c}
@tab Save and compile the source file in the current buffer.
@item @kbd{C-c C-d C-e}
@tab Compile and run the current region.
@item @kbd{C-c C-d C-x}
@tab Go to next syntax error.
@item @kbd{C-c C-d C-v}
@tab Switch to electric debug mode.
@item @kbd{C-c C-d C-b}
@tab Set a breakpoint at the nearest viable source line.
@item @kbd{C-c C-d C-d}
@tab Clear the nearest breakpoint.
@item @kbd{C-c C-d [}
@tab Go to the previous breakpoint.
@item @kbd{C-c C-d ]}
@tab Go to the next breakpoint.
@item @kbd{C-c C-d C-p}
@tab Print the value of the expression near point in IDL.
@end multitable

@subheading Commonly used Settings in @file{.emacs}
@lisp
;; 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))
@end lisp

@html
<A NAME="TUTORIAL"></A>
@end html

@node Getting Started, The IDLWAVE Major Mode, IDLWAVE in a Nutshell, Top
@chapter Getting Started (Tutorial)
@cindex Quick-Start
@cindex Tutorial
@cindex Getting Started

@menu
* Lesson I -- Development Cycle::  
* Lesson II -- Customization::  
* Lesson III -- User Catalog::  
@end menu

@node  Lesson I -- Development Cycle, Lesson II -- Customization, Getting Started, Getting Started
@section 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 or XEmacs with the full
IDLWAVE package including online help (@pxref{Installation}).  We also
assume that you are familiar with Emacs and can read the nomenclature of
key presses in Emacs (in particular, @kbd{C} stands for @key{CONTROL}
and @kbd{M} for @key{META} (often the @key{ALT} key carries this
functionality)).

Open a new source file by typing:

@example
@kbd{C-x C-f tutorial.pro @key{RET}}
@end example

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 @samp{IDLWAVE}.

Now cut-and-paste the following code, also available as
@file{tutorial.pro} in the IDLWAVE distribution.

@example
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
end
     
function weekday,day,month,year
  ;; compute weekday number for date
  nr = daynr(day,month,year)
  return, nr mod 7
end
     
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])
  end
  plot,years,wdays,YS=2,YT="Wday (0=Sunday)"
end
@end example

The indentation probably looks funny, since it's different from the
settings you use, so use the @key{TAB} key in each line to
automatically line it up (or, more quickly, @emph{select} the entire
buffer with @kbd{C-x h}, and indent the whole region with
@kbd{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 @code{end} statement of the @code{for} loop and press
@key{SPC}.  IDLWAVE blinks back to the beginning of the block and
changes the generic @code{end} to the specific @code{endfor}
automatically (as long as the variable @code{idlwave-expand-generic-end}
is turned on --- @pxref{Lesson II -- Customization}).  Now place the
cursor in any line you would like to split and press @kbd{M-@key{RET}}.
The line is split at the cursor position, with the continuation @samp{$}
and indentation all taken care of.  Use @kbd{C-/} to undo the last
change.

The procedure @code{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
@kbd{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 @code{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 @kbd{C-c C-d C-c} to compile
the program.  If you watch the shell buffer, you see that IDLWAVE types
@samp{.run "tutorial.pro"} for you.  But the compilation fails because
there is a comma in the line @samp{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 @kbd{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 @samp{plot_} and hit @key{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 @w{@code{plot_wday}} should be one of
them.  Saving the buffer alerted IDLWAVE about this new routine.
Click with the middle mouse button on @code{plot_wday} and it will be
copied to the shell buffer, or if you prefer, add @samp{w} to
@samp{plot_} to make it unambiguous (depending on what other routines
starting with @samp{plot_} you have installed on your system), hit
@key{TAB} again, and the full routine name will be completed.  Now
provide the two arguments:

@example
plot_wday,1,1
@end example

@noindent and press @key{RET}.  This fails with an error message telling
you the @code{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 @kbd{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 @code{YTITLE}.  Fix that up.
Recompile with @kbd{C-c C-d C-c}. Jump back into the shell with
@kbd{C-c C-s}, press the @key{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 @code{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
@kbd{M-@key{Tab}}.  A long list of plot's keywords appears.  Aha,
there it is, @code{PSYM}.  Middle click to insert it.  An @samp{=}
sign is included for you too.  Now what were the values of @code{PSYM}
supposed to be?  With the cursor on or after the keyword, press
@kbd{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 @code{PYSM} keyword.
OK, let's use diamonds=4.  Fix this, recompile (you know the command
by now: @kbd{C-c C-d C-c}), go back to the shell (if it's vanished,
you know what to do: @kbd{C-c C-s}) and execute again.  Now things
look pretty good.

Let's try a different day --- how about April fool's day?

@example
plot_wday,1,4
@end example

Oops, this looks very wrong.  All April Fool's days cannot be Fridays!
We've got a bug in the program, perhaps in the @code{daynr} function.
Let's put a breakpoint on the last line there.  Position the cursor on
the @samp{return, d+...} line and press @kbd{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:
@samp{d}, @samp{y}, @samp{m}, @samp{y1}, etc.  Maybe @code{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, @samp{y1} is zero,
but it should be the year, depending on delta.  Shift click
@samp{delta} to see that it's 0.  Below, we see the offending line:
@samp{y1=y*delta...} the multiplication should have been a minus sign!
Hit @kbd{q} to exit the debugging mode, and fix the line to read:

@example
y1 = y - delta
@end example

Now remove all breakpoints: @kbd{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.

@node  Lesson II -- Customization, Lesson III -- User Catalog, Lesson I -- Development Cycle, Getting Started
@section 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 @file{.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 @samp{t} means on, a value
of @samp{nil} means off.  Copy the following line into your
@file{.emacs} file, exit and restart Emacs.

@lisp
(setq idlwave-reserved-word-upcase t)
@end lisp

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 @key{SPC}
or @key{RET} right after the word.  Try it out!  @samp{if} changes to
@samp{IF}, @samp{begin} to @samp{BEGIN}.  If you don't like this
behavior, remove the option again from your @file{.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
@code{BEGIN} and @code{END}.  Try the following lines in @file{.emacs}:

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

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

If you cannot seem to master this Lisp customization in @file{.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
@file{.pro} buffers, menu item @code{Customize->Browse IDLWAVE
Group}. Here you'll be presented with all the various variables grouped
into categories.  You can navigate the hierarchy (e.g. @samp{IDLWAVE
Code Formatting->Idlwave Abbrev And Indent Action->Idlwave Expand
Generic End} to turn on @code{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 @kbd{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 @key{CONTROL} and @key{SHIFT} while pressing
a single character: @kbd{C-S-b} for setting a breakpoint, @kbd{C-S-c}
for compiling the current source file, @kbd{C-S-a} for deleting all
breakpoints (try it, it's easier).  You can enable this with:

@lisp
(setq idlwave-shell-debug-modifiers '(shift control))
@end lisp

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

@lisp
(setq idlwave-shell-debug-modifiers '(super))
@end lisp

@noindent to get compilation on @kbd{S-c}.  Often, a modifier key like
@key{SUPER} or @key{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
@emph{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.

@lisp
;; 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)))
@end lisp

@node  Lesson III -- User Catalog,  , Lesson II -- Customization, Getting Started
@section 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 @kbd{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 JHUPL
or the IDL-Astro library?  In many cases, you may already have this
information.  Files named @file{.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
@file{.idlwave_catalog} files, or using the built-in method to create a
single ``user catalog'', which we'll show here.  @xref{Catalogs}, for
more information on choosing which method to use.

To build a user catalog, select @code{Routine Info/Select Catalog
Directories} from the IDLWAVE entry in the menu bar.  If necessary,
start the shell first with @kbd{C-c C-s} (@pxref{Starting the Shell}).
IDLWAVE will find out about the IDL @code{!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 @samp{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 @file{.idlwave/idlusercat.el} in your home
directory 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 (@kbd{C-c ?}) or completion
(@kbd{M-@key{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:

@example
    a=readf@key{M-@key{TAB}}
@end example

expands to `readfits('.  Then try

@example
    a=readfits(@key{C-c ?}
@end example

and you get:

@example
Usage:    Result = READFITS(filename, header, heap)
...
@end example

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 @kbd{C-h v idlwave<-variable-name> @key{RET}}) and ask the
remaining questions on the newsgroup @code{comp.lang.idl-pvwave}.

@node The IDLWAVE Major Mode, The IDLWAVE Shell, Getting Started, Top
@chapter The IDLWAVE Major Mode
@cindex IDLWAVE major mode
@cindex Major mode, @code{idlwave-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.

@menu
* Code Formatting::             Making code look nice
* Routine Info::                Calling Sequence and Keyword List
* Online Help::                 One key press from source to help
* Completion::                  Completing routine names and Keywords
* Routine Source::              Finding routines, the easy way
* Resolving Routines::          Force the Shell to compile a routine
* Code Templates::              Frequent code constructs
* Abbreviations::               Abbreviations for common commands
* Actions::                     Changing case, Padding, End checking
* Doc Header::                  Inserting a standard header
* Motion Commands::             Moving through the structure of a program
* Misc Options::                Things that fit nowhere else
@end menu

@node Code Formatting, Routine Info, The IDLWAVE Major Mode, The IDLWAVE Major Mode
@section Code Formatting
@cindex Code formatting
@cindex Formatting, of code

@menu
* Code Indentation::            Reflecting the logical structure
* Continued Statement Indentation::  
* Comment Indentation::         Special indentation for comment lines
* Continuation Lines::          Splitting statements over lines
* Syntax Highlighting::         Font-lock support
* Octals and Highlighting::     Why "123 causes problems
@end menu

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.


@node Code Indentation, Continued Statement Indentation, Code Formatting, Code Formatting
@subsection Code Indentation
@cindex Code indentation
@cindex Indentation

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

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

@defopt idlwave-main-block-indent (@code{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.
@end defopt

@defopt idlwave-block-indent (@code{3})
Extra indentation applied to block lines.  If you change this, you
probably also want to change @code{idlwave-end-offset}.
@end defopt

@defopt idlwave-end-offset (@code{-3})
Extra indentation applied to block END lines.  A value equal to negative
@code{idlwave-block-indent} will make END lines line up with the block
BEGIN lines.
@end defopt

@node Continued Statement Indentation, Comment Indentation, Code Indentation, Code Formatting
@subsection Continued Statement Indentation
@cindex Indentation, continued statement
@cindex Continued statement indentation
Continuation lines (following a line ending with @code{$}) 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 (@code{,},@code{(},@code{@{},@code{[},@code{=}).  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:

@example
function foo, a, b,  $
              c, d
  bar =  sin( a + b + $
              c + d)
end
@end example
@noindent

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:

@example
function thisfunctionnameisverylongsoitwillleavelittleroom, a, b, $
                                                            c, d
@end example

You can instruct IDLWAVE when to avoid using this special continuation
indentation by setting the variable
@code{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
@code{idlwave-continuation-indent}).  As a special case, continuations
of routine calls without any arguments or keywords will @emph{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
@code{idlwave-max-extra-continuation-indent} is small, the key
@kbd{C-u @key{TAB}} will re-indent all lines in the current statement.
Note that @code{idlwave-indent-to-open-paren}, if non-@code{nil},
overrides the @code{idlwave-max-extra-continuation-indent} limit, for
parentheses only, forcing them always to line up.


@defopt idlwave-continuation-indent (@code{2})
Extra indentation applied to normal continuation lines.
@end defopt

@defopt idlwave-max-extra-continuation-indent (@code{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 @code{0}.  To enable it
constantly, set to a large number (like @code{100}).  Note that the
indentation in a long continued statement never decreases from line to
line, outside of nested parentheses statements.
@end defopt

@defopt idlwave-indent-to-open-paren (@code{t})
Non-@code{nil} means indent continuation lines to innermost open
parenthesis, regardless of whether the
@code{idlwave-max-extra-continuation-indent} limit is satisfied.
@end defopt

@node Comment Indentation, Continuation Lines, Continued Statement Indentation, Code Formatting
@subsection Comment Indentation
@cindex Comment indentation
@cindex Hanging paragraphs
@cindex Paragraphs, filling
@cindex Paragraphs, hanging

In IDL, lines starting with a @samp{;} are called @emph{comment lines}.
Comment lines are indented as follows:

@multitable @columnfractions .1 .90
@item @code{;;;}
@tab The indentation of lines starting with three semicolons remains
unchanged.
@item @code{;;}
@tab Lines starting with two semicolons are indented like the surrounding code.
@item @code{;}
@tab Lines starting with a single semicolon are indented to a minimum column.
@end multitable

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

@defopt idlwave-no-change-comment
The indentation of a comment starting with this regexp will not be
changed.
@end defopt

@defopt idlwave-begin-line-comment
A comment anchored at the beginning of line.
@end defopt

@defopt idlwave-code-comment
A comment that starts with this regexp is indented as if it is a part of
IDL code.
@end defopt

@node Continuation Lines, Syntax Highlighting, Comment Indentation, Code Formatting
@subsection Continuation Lines and Filling
@cindex Continuation lines
@cindex Line splitting
@cindex String splitting
@cindex Splitting, of lines

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

@cindex Filling
@cindex @code{auto-fill-mode}
@cindex Hanging paragraphs
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 @code{auto-fill-mode} is turned
on (toggle with @kbd{C-c C-a}), comments will be auto-filled.  If the
first line of a paragraph contains a match for
@code{idlwave-hang-indent-regexp} (a dash-space by default), subsequent
lines are positioned to line up after it, as in the following example.

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

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

@defopt idlwave-fill-comment-line-only (@code{t})
Non-@code{nil} means auto fill will only operate on comment lines.
@end defopt

@defopt idlwave-auto-fill-split-string (@code{t})
Non-@code{nil} means auto fill will split strings with the IDL @samp{+}
operator.
@end defopt

@defopt idlwave-split-line-string (@code{t})
Non-@code{nil} means @code{idlwave-split-line} will split strings with
@samp{+}.
@end defopt

@defopt idlwave-hanging-indent (@code{t})
Non-@code{nil} means comment paragraphs are indented under the hanging
indent given by @code{idlwave-hang-indent-regexp} match in the first
line of the paragraph.
@end defopt

@defopt idlwave-hang-indent-regexp (@code{"- "})
Regular expression matching the position of the hanging indent
in the first line of a comment paragraph.
@end defopt

@defopt idlwave-use-last-hang-indent (@code{nil})
Non-@code{nil} means use last match on line for
@code{idlwave-indent-regexp}. 
@end defopt

@node Syntax Highlighting, Octals and Highlighting, Continuation Lines, Code Formatting
@subsection Syntax Highlighting
@cindex Syntax highlighting
@cindex Highlighting of syntax
@cindex Font lock

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

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

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

@defopt idlwave-default-font-lock-items
Items which should be fontified on the default fontification level
2. 
@end defopt

@node Octals and Highlighting,  , Syntax Highlighting, Code Formatting
@subsection Octals and Highlighting
@cindex Syntax highlighting, Octals
@cindex Highlighting of syntax, Octals

A rare syntax highlighting problem results from an extremely unfortunate
notation for octal numbers in IDL: @code{"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:

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

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

@example
   string('305'OB) + ' is an Angstrom.'
@end example

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

@node Routine Info, Online Help, Code Formatting, The IDLWAVE Major Mode
@section Routine Info
@cindex Routine info
@cindex Updating routine info
@cindex Scanning buffers for routine info
@cindex Buffers, scanning for routine info
@cindex Shell, querying for routine info

@kindex C-c C-i
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
@samp{.pro} routines on your system than IDL itself!  It maintains a
list of all built-in routines, with calling sequences and
keywords@footnote{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.}.  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 @kbd{C-c C-i}
(@code{idlwave-update-routine-info}).

@kindex C-c ?
To display the information about a routine, press @kbd{C-c ?}, which
calls the command @code{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:

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

@cindex Default routine, for info and help
On positions 1,2 and 8, information about the @samp{plot} procedure will
be shown.  On positions 3,4, and 7, the @samp{alog} function will be
described, while positions 5 and 6 will investigate the @samp{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
@samp{->} operator (@pxref{Object Method Completion and Class
Ambiguity}), or by having been explicitly included in the call
(e.g. @code{a->myclass::Foo}).

@cindex Calling sequences
@cindex Keywords of a routine
@cindex Routine source information
The description displayed contains the calling sequence, the list of
keywords and the source location of this routine.  It looks like this:

@example
Usage:    XMANAGER, NAME, ID
Keywords: BACKGROUND CATCH CLEANUP EVENT_HANDLER GROUP_LEADER
          JUST_REG MODAL NO_BLOCK
Source:   SystemLib   [LCSB] /soft1/idl53/lib/xmanager.pro
@end example

@cindex Categories, of routines
@cindex Load-path shadows
@cindex Shadows, load-path
@cindex IDL variable @code{!PATH}
@cindex @code{!PATH}, IDL variable
@cindex IDL variable @code{!DIR}
@cindex @code{!DIR}, IDL variable

If a definition of this routine exists in several files accessible to
IDLWAVE, several @samp{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
(@pxref{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 (@pxref{Catalogs}).
The source entry consists of a @emph{source category}, a set of
@emph{flags} and the path to the @emph{source file}.  The following
default categories exist:

@multitable @columnfractions .15 .85
@item @i{System}
@tab A system routine of unknown origin.  When the system library has
been scanned as part of a catalog (@pxref{Catalogs}), this category
will automatically split into the next two.
@item @i{Builtin}
@tab A builtin system routine with no source code available.
@item @i{SystemLib}
@tab A library system routine in the official lib directory @file{!DIR/lib}.
@item @i{Obsolete}
@tab A library routine in the official lib directory @file{!DIR/lib/obsolete}.
@item @i{Library}
@tab A routine in a file on IDL's search path @code{!PATH}.
@item @i{Other}
@tab Any other routine with a file not known to be on the search path.
@item @i{Unresolved}
@tab An otherwise unknown routine the shell lists as unresolved 
(referenced, but not compiled).
@end multitable

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

@cindex Flags, in routine info
@cindex Duplicate routines
@cindex Multiply defined routines
@cindex Routine definitions, multiple
The flags @code{[LCSB]} indicate the source of the information IDLWAVE
has regarding the file: from a library catalog (@w{@code{[L---]}}),
from a user catalog (@w{@code{[-C--]}}, from the IDL Shell
(@w{@code{[--S-]}}) or from an Emacs buffer (@w{@code{[---B]}}).
Combinations are possible (a compiled library routine visited in a
buffer might read @w{@code{[L-SB]}}).  If a file contains multiple
definitions of the same routine, the file name will be prefixed with
@samp{(Nx)} where @samp{N} is the number of definitions.

@cindex Online Help from the routine info buffer
@cindex Active text, in routine info
@cindex Inserting keywords, from routine info
@cindex Source file, access from routine info
Some of the text in the @file{*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:

@multitable @columnfractions 0.15 0.85
@item @i{Usage}
@tab If online help is installed, a click with the @emph{right} mouse
button on the @i{Usage:} line will access the help for the
routine (@pxref{Online Help}).  
@item @i{Keyword}
@tab Online help about keywords is also available with the
@emph{right} mouse button.  Clicking on a keyword with the @emph{middle}
mouse button will insert this keyword in the buffer from where
@code{idlwave-routine-info} was called.  Holding down @key{SHIFT} while
clicking also adds the initial @samp{/}.
@item @i{Source}
@tab Clicking with the @emph{middle} mouse button on a @samp{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
@kbd{C-c ?} was called.  If you use the @emph{right} mouse button, the
source will not be visited by a buffer, but displayed in the online help
window.
@item @i{Classes}
@tab The @i{Classes} line is only included in the routine info window if
the current class inherits from other classes.  You can click with the
@emph{middle} mouse button to display routine info about the current
method in other classes on the inheritance chain, if such a method
exists there.
@end multitable

@defopt idlwave-resize-routine-help-window (@code{t})
Non-@code{nil} means resize the Routine-info @file{*Help*} window to
fit the content.
@end defopt

@defopt idlwave-special-lib-alist
Alist of regular expressions matching special library directories.
@end defopt

@defopt idlwave-rinfo-max-source-lines (@code{5})
Maximum number of source files displayed in the Routine Info window.
@end defopt


@html
<A NAME="ONLINE_HELP"></A>
@end html
@node Online Help, Completion, Routine Info, The IDLWAVE Major Mode
@section Online Help

@cindex Online Help
@cindex @file{idlw-help.txt}
@cindex @file{idlw-help.el}
@cindex Installing online help
@cindex Online Help, Installation
@cindex Speed, of online help
@cindex XML Help Catalog

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 @emph{much}
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 @code{idlwave_config_directory}
(@file{~/.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 @code{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.

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.

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

@cindex Context, for online help
@multitable @columnfractions .25 .75
@item @i{Routine names}
@tab The name of a routine (function, procedure, method).
@item @i{Keyword Parameters}
@tab A keyword parameter of a routine.
@item @i{System Variables}
@tab System variables like @code{!DPI}.
@item @i{System Variable Tags}
@tab System variables tags like @code{!D.X_SIZE}.
@item @i{IDL Statements}
@tab Statements like @code{PRO}, @code{REPEAT}, @code{COMPILE_OPT}, etc.
@item @i{IDL Controls}
@tab Control structures like @code{FOR}, @code{SWITCH}, etc.
@item @i{Class names}
@tab A class name in an @code{OBJ_NEW} call.
@item @i{Class Init Keywords}
@tab Beyond the class name in an @code{OBJ_NEW} call.
@item @i{Executive Command}
@tab An executive command like @code{.RUN}.  Mostly useful in the shell.
@item @i{Structure Tags}
@tab Structure tags like @code{state.xsize}
@item @i{Class Tags}
@tab Class tags like @code{self.value}.
@item @i{Default}
@tab The routine that would be selected for routine info display.
@end multitable

@cindex @code{OBJ_NEW}, special online help
Note that the @code{OBJ_NEW} function is special in that the help
displayed depends on the cursor position.  If the cursor is on the
@samp{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 @emph{after} the class name, anywhere in the argument
list, the documentation for the corresponding @code{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.

@itemize @bullet
@item
Online help for routines and keywords can be accessed through the
Routine Info display.  Click with @kbd{Mouse-3} on an item to see the
corresponding help (@pxref{Routine Info}).
@item
When using completion and Emacs pops up a @file{*Completions*} buffer
with possible completions, clicking with @kbd{Mouse-3} on a completion
item invokes help on that item (@pxref{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).
@end itemize
@noindent
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.


@menu
* Help with HTML Documentation::  
* Help with Source::            
@end menu

@node Help with HTML Documentation, Help with Source, Online Help, Online Help
@subsection Help with HTML Documentation
@cindex HTML Help
@cindex Help using HTML manuals
@cindex IDL manual, HTML version
@cindex IDL Assistant

Help using the HTML documentation is invoked with the built-in Emacs
command @code{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 @emph{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
@code{idlwave-help-use-assistant} controls whether this browser is
used.  Note that, due to limitations in the Assistant, invoking help
within IDLWAVE and @code{? 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
@code{idlwave-help-browser-function} controls which browser help is sent
to (as long as @code{idlwave-help-use-assistant} is not set).  This
function is used to set the variable @code{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
@code{w3} (bundled with many versions of Emacs) and @code{w3m}
(@uref{http://emacs-w3m.namazu.org/}) 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 @code{idlwave-help-browser-is-local}.

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

@xref{HTML Help Browser Tips}, for more information on selecting and
configuring a browser for use with IDL's HTML help system.

@defopt idlwave-html-system-help-location @file{help/online_help}
Relative directory of the system-supplied HTML help directory,
considered with respect to @code{idlwave-system-directory}.  Relevant
for IDL 6.2 and greater.  Should not change.
@end defopt     

@defopt idlwave-html-help-location @file{/usr/local/etc/}
The directory where the @file{idl_html_help} HTML directory live.
Obsolete and ignored for IDL 6.2 and greater
(@code{idlwave-html-system-help-location} is used instead).
@end defopt

@defopt idlwave-help-use-assistant @code{t}
If set, use the IDL Assistant if possible for online HTML help,
otherwise use the browser function specified in
@code{idlwave-help-browser-function}.
@end defopt

@defopt idlwave-help-browser-function
The browser function to use to display IDLWAVE HTML help.  Should be
one of the functions available for setting
@code{browse-url-browser-function}, which see.
@end defopt

@defopt idlwave-help-browser-is-local
Is the browser selected in @code{idlwave-help-browser-function} run in a
local Emacs buffer or window?  Defaults to @code{t} if the function
contains "-w3".
@end defopt

@defopt idlwave-help-link-face
The face for links to IDLWAVE online help.
@end defopt

@node Help with Source,  , Help with HTML Documentation, Online Help
@subsection Help with Source
@cindex Help using routine source

@cindex Source code, as online help
@cindex DocLib header, as online help
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
(@code{pro}/@code{function}) is shown.  The doclib header sections which
are searched for include @samp{NAME} and @samp{KEYWORDS}.  Localization
support can be added by customizing the @code{idlwave-help-doclib-name}
and @code{idlwave-help-doclib-keyword} variables.

@cindex Structure tags, in online help
@cindex Class tags, in online help
Help is also available for class structure tags (@code{self.TAG}), and
generic structure tags, if structure tag completion is enabled
(@pxref{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:

@multitable  @columnfractions .15 .85
@item @kbd{@key{SPACE}}
@tab Scroll forward one page.
@item @kbd{@key{RET}}
@tab Scroll forward one line.
@item @kbd{@key{DEL}}
@tab Scroll back one page.
@item @kbd{h}
@tab Jump to DocLib Header of the routine whose source is displayed
as help.
@item @kbd{H}
@tab Jump to the first DocLib Header in the file.
@item @kbd{.} @r{(Dot)}
@tab Jump back and forth between the routine definition (the
@code{pro}/@code{function} statement) and the description of the help
item in the DocLib header.
@item @kbd{F}
@tab Fontify the buffer like source code.  See the variable @code{idlwave-help-fontify-source-code}.
@item @kbd{q}
@tab Kill the help window.
@end multitable


@defopt idlwave-help-use-dedicated-frame (@code{nil})
Non-@code{nil} means use a separate frame for Online Help if possible.
@end defopt

@defopt idlwave-help-frame-parameters
The frame parameters for the special Online Help frame.
@end defopt

@defopt idlwave-max-popup-menu-items (@code{20})
Maximum number of items per pane in pop-up menus.
@end defopt

@defopt idlwave-extra-help-function
Function to call for help if the normal help fails.
@end defopt

@defopt idlwave-help-fontify-source-code (@code{nil})
Non-@code{nil} means fontify source code displayed as help.
@end defopt

@defopt idlwave-help-source-try-header (@code{t})
Non-@code{nil} means try to find help in routine header when
displaying source file.
@end defopt

@defopt idlwave-help-doclib-name (@code{"name"})
The case-insensitive heading word in doclib headers to locate the
@emph{name} section.  Can be a regexp, e.g. @code{"\\(name\\|nom\\)"}.
@end defopt

@defopt idlwave-help-doclib-keyword (@code{"KEYWORD"})
The case-insensitive heading word in doclib headers to locate the
@emph{keywords} section.  Can be a regexp.
@end defopt


@node Completion, Routine Source, Online Help, The IDLWAVE Major Mode
@section Completion
@cindex Completion
@cindex Keyword completion
@cindex Method completion
@cindex Object method completion
@cindex Class name completion
@cindex Function name completion
@cindex Procedure name completion

@kindex M-@key{TAB}
@kindex C-c C-i
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 @kbd{M-@key{TAB}} (or simply @kbd{@key{TAB}} in the IDLWAVE
Shell --- @pxref{Using the Shell}).  Completion uses exactly the same
internal information as routine info, so when necessary (rarely) it can
be updated with @kbd{C-c C-i} (@code{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 @kbd{M-@key{TAB}} would try to complete when the cursor is on the
position marked with a @samp{_}:

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

@cindex Completion, ambiguity
@cindex Completion, forcing function name
The only place where completion is ambiguous is procedure/function
@emph{keywords} versus @emph{functions}.  After @samp{plot,x,_}, IDLWAVE
will always assume a keyword to @samp{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: @kbd{C-u M-@key{TAB}}.

Giving two prefix arguments (@kbd{C-u C-u M-@key{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.

@cindex Scrolling the @file{*Completions*} window
@cindex Completion, scrolling
@cindex Completion, Online Help
@cindex Online Help in @file{*Completions*} buffer
If the list of completions is too long to fit in the
@file{*Completions*} window, the window can be scrolled by pressing
@kbd{M-@key{TAB}} repeatedly.  Online help (if installed) for each
possible completion is available by clicking with @kbd{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.

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

@defopt idlwave-keyword-completion-adds-equal (@code{t})
Non-@code{nil} means completion automatically adds @samp{=} after
completed keywords.
@end defopt

@defopt idlwave-function-completion-adds-paren (@code{t})
Non-@code{nil} means completion automatically adds @samp{(} after
completed function.  A value of `2' means also add the closing
parenthesis and position the cursor between the two.
@end defopt

@defopt idlwave-completion-restore-window-configuration (@code{t})
Non-@code{nil} means restore window configuration after successful
completion.
@end defopt

@defopt idlwave-highlight-help-links-in-completion (@code{t})
Non-@code{nil} means highlight completions for which system help is
available.
@end defopt

@menu
* Case of Completed Words::     CaseOFcomPletedWords
* Object Method Completion and Class Ambiguity::  obj->Method, what?
* Object Method Completion in the Shell::  
* Class and Keyword Inheritance::  obj->Method, _EXTRA=e
* Structure Tag Completion::    Completing state.Tag
@end menu

@node  Case of Completed Words, Object Method Completion and Class Ambiguity, Completion, Completion
@subsection Case of Completed Words
@cindex Case of completed words
@cindex Mixed case completion
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 @code{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
@code{(routine . preserve)} in that variable.  To enable total control
over the case of completed items, independent of buffer context, set
@code{idlwave-completion-force-default-case} to non-@code{nil}.

@defopt idlwave-completion-case
Association list setting the case (UPPER/lower/Capitalized/MixedCase...)
of completed words.
@end defopt

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

@defopt idlwave-complete-empty-string-as-lower-case (@code{nil})
Non-@code{nil} means the empty string is considered lower case for
completion.
@end defopt

@node  Object Method Completion and Class Ambiguity, Object Method Completion in the Shell, Case of Completed Words, Completion
@subsection Object Method Completion and Class Ambiguity
@cindex Object methods
@cindex Class ambiguity
@cindex @code{self} object, default class
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 @emph{all} known classes which contain that method will be
considered for keyword completion.  In the @file{*Completions*} buffer,
the matching classes will be shown next to each item (see option
@code{idlwave-completion-show-classes}).  As a special case, the class
of an object called @samp{self} is always taken to be the class of the
current routine, when in an IDLWAVE buffer.  All inherits classes are
considered as well.

@cindex Forcing class query.
@cindex Class query, forcing
You can also call @code{idlwave-complete} with a prefix arg: @kbd{C-u
M-@key{TAB}}.  IDLWAVE will then prompt you for the class in order to
narrow down the number of possible completions.  The variable
@code{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. @code{Init,SetProperty,GetProperty}).  

@cindex Saving object class on @code{->}
@cindex @code{->}
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 @samp{->},
after which the operator will be shown in a different face (bold by
default).  The variable @code{idlwave-store-inquired-class} can be used
to turn it off or on.

@defopt idlwave-completion-show-classes (@code{1})
Non-@code{nil} means show up to that many classes in
@file{*Completions*} buffer when completing object methods and
keywords.
@end defopt

@defopt idlwave-completion-fontify-classes (@code{t})
Non-@code{nil} means fontify the classes in completions buffer.
@end defopt

@defopt idlwave-query-class (@code{nil})
Association list governing query for object classes during completion.
@end defopt

@defopt idlwave-store-inquired-class (@code{t})
Non-@code{nil} means store class of a method call as text property on
@samp{->}.
@end defopt

@defopt idlwave-class-arrow-face
Face to highlight object operator arrows @samp{->} which carry a saved
class text property.
@end defopt

@node Object Method Completion in the Shell, Class and Keyword Inheritance, Object Method Completion and Class Ambiguity, Completion
@subsection Object Method Completion in the Shell
@cindex Method Completion in Shell
In the IDLWAVE Shell (@pxref{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
@code{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). 

@node   Class and Keyword Inheritance, Structure Tag Completion, Object Method Completion in the Shell, Completion
@subsection Class and Keyword Inheritance
@cindex Inheritance, class
@cindex Keyword inheritance
@cindex Inheritance, keyword

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 (@pxref{Routine Info}), as long as variable
@code{idlwave-support-inheritance} is non-@code{nil}.

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

IDLWAVE can accommodate this special synergy between class and keyword
inheritance: if @code{_EXTRA} or @code{_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 @code{idlwave-keyword-class-inheritance} can be used to
configure which methods have keyword inheritance treated in this
simple, class-driven way.  By default, only @code{Init} and
@code{(Get|Set)Property} are.  The completion buffer will label
keywords based on their originating class.

@defopt idlwave-support-inheritance (@code{t})
Non-@code{nil} means consider inheritance during completion, online help etc.
@end defopt

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

@node    Structure Tag Completion,  , Class and Keyword Inheritance, Completion
@subsection Structure Tag Completion
@cindex Completion, structure tag
@cindex Structure tag completion

In many programs, especially those involving widgets, large structures
(e.g. the @samp{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 @samp{self}
object (@pxref{Object Method Completion and Class Ambiguity}).  Add-in
code for structure tag completion is available in the form of a loadable
completion module: @file{idlw-complete-structtag.el}.  Tag completion in
structures is highly ambiguous (much more so than @samp{self}
completion), so @code{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. @samp{state}), structure tags which are read from its definition
in the same file can be used for completion.

Structure tag completion is not enabled by default.  To enable it,
simply add the following to your @file{.emacs}:

@lisp
   (add-hook 'idlwave-load-hook 
             (lambda () (require 'idlw-complete-structtag)))
@end lisp

Once enabled, you'll also be able to access online help on the structure
tags, using the usual methods (@pxref{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.:

@example
IDL> st.[Tab]
@end example

@noindent will complete with all structure fields of the structure
@code{st}.

@node Routine Source, Resolving Routines, Completion, The IDLWAVE Major Mode
@section Routine Source
@cindex Routine source file
@cindex Module source file
@cindex Source file, of a routine
@kindex C-c C-v
In addition to clicking on a @i{Source:} line in the routine info
window, there is another way to quickly visit the source file of a
routine.  The command @kbd{C-c C-v} (@code{idlwave-find-module}) asks
for a module name, offering the same default as
@code{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 (@kbd{C-u C-c C-v})
or the convenience binding @kbd{C-c C-t}.

@cindex Buffers, killing
@cindex Killing autoloaded buffers
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 @kbd{C-c C-k}
(@code{idlwave-kill-autoloaded-buffers}) can be used to easily remove
these buffers.

@node Resolving Routines, Code Templates, Routine Source, The IDLWAVE Major Mode
@section Resolving Routines
@cindex @code{RESOLVE_ROUTINE}
@cindex Compiling library modules
@cindex Routines, resolving

The key sequence @kbd{C-c =} calls the command @code{idlwave-resolve}
and sends the line @samp{RESOLVE_ROUTINE, '@var{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.

@code{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 (@pxref{Catalogs}).
Routine info on modules will then be available without the need to
compile the modules first, and even without a running shell.

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

@node Code Templates, Abbreviations, Resolving Routines, The IDLWAVE Major Mode
@section Code Templates
@cindex Code templates
@cindex Templates

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

@multitable @columnfractions .15 .85
@item @kbd{C-c C-c}
@tab @code{CASE} statement template
@item @kbd{C-c C-f}
@tab @code{FOR} loop template
@item @kbd{C-c C-r}
@tab @code{REPEAT} loop template
@item @kbd{C-c C-w}
@tab @code{WHILE} loop template
@end multitable

All code templates are also available as abbreviations
(@pxref{Abbreviations}).

@node Abbreviations, Actions, Code Templates, The IDLWAVE Major Mode
@section Abbreviations
@cindex Abbreviations

Special abbreviations exist to enable rapid entry of commonly used
commands.  Emacs abbreviations are expanded by typing text into the
buffer and pressing @key{SPC} or @key{RET}.  The special abbreviations
used to insert code templates all start with a @samp{\} (the backslash),
or, optionally, any other character set in
@code{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 @kbd{M-x
idlwave-list-abbrevs}.

Template abbreviations:

@multitable @columnfractions .15 .85
@item @code{\pr}
@tab @code{PROCEDURE} template
@item @code{\fu}
@tab @code{FUNCTION} template
@item @code{\c}
@tab @code{CASE} statement template
@item @code{\f}
@tab @code{FOR} loop template
@item @code{\r}
@tab @code{REPEAT} loop template
@item @code{\w}
@tab @code{WHILE} loop template
@item @code{\i}
@tab @code{IF} statement template
@item @code{\elif}
@tab @code{IF-ELSE} statement template
@end multitable

String abbreviations:

@multitable @columnfractions .15 .85
@item @code{\ap}
@tab @code{arg_present()}
@item @code{\b}
@tab @code{begin}
@item @code{\cb}
@tab @code{byte()}
@item @code{\cc}
@tab @code{complex()}
@item @code{\cd}
@tab @code{double()}
@item @code{\cf}
@tab @code{float()}
@item @code{\cl}
@tab @code{long()}
@item @code{\co}
@tab @code{common}
@item @code{\cs}
@tab @code{string()}
@item @code{\cx}
@tab @code{fix()}
@item @code{\e}
@tab @code{else}
@item @code{\ec}
@tab @code{endcase}
@item @code{\ee}
@tab @code{endelse}
@item @code{\ef}
@tab @code{endfor}
@item @code{\ei}
@tab @code{endif else if}
@item @code{\el}
@tab @code{endif else}
@item @code{\en}
@tab @code{endif}
@item @code{\er}
@tab @code{endrep}
@item @code{\es}
@tab @code{endswitch}
@item @code{\ew}
@tab @code{endwhile}
@item @code{\g}
@tab @code{goto,}
@item @code{\h}
@tab @code{help,}
@item @code{\ik}
@tab @code{if keyword_set() then}
@item @code{\iap}
@tab @code{if arg_present() then}
@item @code{\ine}
@tab @code{if n_elements() eq 0 then}
@item @code{\inn}
@tab @code{if n_elements() ne 0 then}
@item @code{\k}
@tab @code{keyword_set()}
@item @code{\n}
@tab @code{n_elements()}
@item @code{\np}
@tab @code{n_params()}
@item @code{\oi}
@tab @code{on_ioerror,}
@item @code{\or}
@tab @code{openr,}
@item @code{\ou}
@tab @code{openu,}
@item @code{\ow}
@tab @code{openw,}
@item @code{\p}
@tab @code{print,}
@item @code{\pt}
@tab @code{plot,}
@item @code{\pv}
@tab @code{ptr_valid()}
@item @code{\re}
@tab @code{read,}
@item @code{\rf}
@tab @code{readf,}
@item @code{\rt}
@tab @code{return}
@item @code{\ru}
@tab @code{readu,}
@item @code{\s}
@tab @code{size()}
@item @code{\sc}
@tab @code{strcompress()}
@item @code{\sl}
@tab @code{strlowcase()}
@item @code{\sm}
@tab @code{strmid()}
@item @code{\sn}
@tab @code{strlen()}
@item @code{\sp}
@tab @code{strpos()}
@item @code{\sr}
@tab @code{strtrim()}
@item @code{\st}
@tab @code{strput()}
@item @code{\su}
@tab @code{strupcase()}
@item @code{\t}
@tab @code{then}
@item @code{\u}
@tab @code{until}
@item @code{\wc}
@tab @code{widget_control,}
@item @code{\wi}
@tab @code{widget_info()}
@item @code{\wu}
@tab @code{writeu,}
@end multitable

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

@lisp
(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))))
@end lisp

Notice how the abbreviation (here @emph{wb}) and its expansion
(@emph{widget_base()}) are given as arguments, and the single argument to
@code{idlwave-keyword-abbrev} (here @emph{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 @code{idlwave-abbrev-change-case} and, for reserved word
templates, @code{idlwave-reserved-word-upcase} (@pxref{Case Changes}).

@defopt idlwave-abbrev-start-char (@code{"\"})
A single character string used to start abbreviations in abbrev mode.
Beware of common characters which might naturally occur in sequence with
abbreviation strings.
@end defopt

@defopt idlwave-abbrev-move (@code{t})
Non-@code{nil} means the abbrev hook can move point, e.g. to end up
between the parentheses of a function call.
@end defopt

@node Actions, Doc Header, Abbreviations, The IDLWAVE Major Mode
@section Actions
@cindex Actions
@cindex Coding standards, enforcing

@emph{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:

@itemize @bullet
@item
Some actions are applied directly while typing.  For example, pressing
@samp{=} can run a check to make sure that this operator is surrounded
by spaces and insert these spaces if necessary.  Pressing @key{SPC}
after a reserved word can call a command to change the word to upper
case.
@item
When a line is re-indented with @key{TAB}, actions can be applied to the
entire line.  To enable this, the variable @code{idlwave-do-actions}
must be non-@code{nil}.
@item
@cindex Foreign code, adapting
@cindex Actions, applied to foreign code
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 @kbd{M-x expand-region-abbrevs}.  Useful marking
commands are @kbd{C-x h} (the entire file) or @kbd{C-M-h} (the current
subprogram). @xref{Code Indentation}, for information how to adjust the
indentation of the code.
@end itemize

@defopt idlwave-do-actions (@code{nil})
Non-@code{nil} means performs actions when indenting.  Individual action
settings are described below and set separately.
@end defopt

@menu
* Block Boundary Check::        Is the END statement correct?
* Padding Operators::           Enforcing space around `=' etc
* Case Changes::                Enforcing upper case keywords
@end menu

@node Block Boundary Check, Padding Operators, Actions, Actions
@subsection Block Boundary Check
@cindex Block boundary check
@cindex @code{END} type checking
@cindex @code{END}, automatic insertion
@cindex @code{END}, expanding
@cindex Block, closing
@cindex Closing a block

Whenever you type an @code{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 @code{END}, like
@code{ENDIF} or @code{ENDCASE}, you get a warning if that terminator
does not match the type of block it terminates.

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

@defopt idlwave-show-block (@code{t})
Non-@code{nil} means point blinks to block beginning for
@code{idlwave-show-begin}.
@end defopt

@defopt idlwave-expand-generic-end (@code{t})
Non-@code{nil} means expand generic END to ENDIF/ENDELSE/ENDWHILE etc.
@end defopt

@defopt idlwave-reindent-end (@code{t})
Non-@code{nil} means re-indent line after END was typed.
@end defopt

@node Padding Operators, Case Changes, Block Boundary Check, Actions
@subsection Padding Operators
@cindex Padding operators with spaces
@cindex Operators, padding with spaces
@cindex Space, around 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 @samp{<}, @samp{>}, @samp{,}, @samp{=},
and @samp{->}, as well as the modified assignment operators
(@samp{AND=}, @samp{OR=}, etc.).  This feature is turned off by default.
If you want to turn it on, customize the variables
@code{idlwave-surround-by-blank} and @code{idlwave-do-actions} and turn
both on.  You can also define similar actions for other operators by
using the function @code{idlwave-action-and-binding} in the mode hook.
For example, to enforce space padding of the @samp{+} and @samp{*}
operators (outside of strings and comments, of course), try this in
@file{.emacs}

@lisp
(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))))
@end lisp

Note that the modified assignment operators which begin with a word
(@samp{AND=}, @samp{OR=}, @samp{NOT=}, etc.) require a leading space to
be recognized (e.g @code{vAND=4} would be interpreted as a variable
@code{vAND}).  Also note that, since e.g., @code{>} and @code{>=} are
both valid operators, it is impossible to surround both by blanks while
they are being typed.  Similarly with @code{&} and @code{&&}.  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 @code{idlwave-do-actions} is on).

@defopt idlwave-surround-by-blank (@code{nil})
Non-@code{nil} means enable @code{idlwave-surround}.  If non-@code{nil},
@samp{=}, @samp{<}, @samp{>}, @samp{&}, @samp{,}, @samp{->}, and the
modified assignment operators (@samp{AND=}, @samp{OR=}, etc.) are
surrounded with spaces by @code{idlwave-surround}.
@end defopt

@defopt idlwave-pad-keyword (@code{t})
Non-@code{nil} means space-pad the @samp{=} in keyword assignments.
@end defopt

@node Case Changes,  , Padding Operators, Actions
@subsection Case Changes
@cindex Case changes
@cindex Upcase, enforcing for reserved words
@cindex Downcase, enforcing for reserved words

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

@lisp
(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)))
@end lisp

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

@defopt idlwave-abbrev-change-case (@code{nil})
Non-@code{nil} means all abbrevs will be forced to either upper or lower
case.  Valid values are @code{nil}, @code{t}, and @code{down}.
@end defopt

@defopt idlwave-reserved-word-upcase (@code{nil})
Non-@code{nil} means reserved words will be made upper case via abbrev
expansion.
@end defopt


@node Doc Header, Motion Commands, Actions, The IDLWAVE Major Mode
@section Documentation Header
@cindex Documentation header
@cindex DocLib header
@cindex Modification timestamp
@cindex Header, for file documentation
@cindex Timestamp, in doc header.
@cindex Changelog, in doc header.

@kindex C-c C-h
@kindex C-c C-m
The command @kbd{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 @code{idlwave-file-header}).  One of the keywords is
@samp{MODIFICATION HISTORY} under which the changes to a routine can be
recorded.  The command @kbd{C-c C-m} jumps to the @samp{MODIFICATION
HISTORY} of the current routine or file and inserts the user name with a
timestamp.

@defopt idlwave-file-header
The doc-header template or a path to a file containing it.
@end defopt

@defopt idlwave-header-to-beginning-of-file (@code{nil})
Non-@code{nil} means the documentation header will always be at start
of file.
@end defopt

@defopt idlwave-timestamp-hook
The hook function used to update the timestamp of a function.
@end defopt

@defopt idlwave-doc-modifications-keyword
The modifications keyword to use with the log documentation commands.
@end defopt

@defopt idlwave-doclib-start
Regexp matching the start of a document library header.
@end defopt

@defopt idlwave-doclib-end
Regexp matching the start of a document library header.
@end defopt

@node Motion Commands, Misc Options, Doc Header, The IDLWAVE Major Mode
@section Motion Commands
@cindex Motion commands
@cindex Program structure, moving through
@cindex Code structure, moving through
@cindex @file{Func-menu}, XEmacs package
@cindex @file{Imenu}, Emacs package
@cindex Function definitions, jumping to
@cindex Procedure definitions, jumping to

IDLWAVE supports both @file{Imenu} and @file{Func-menu}, two packages
which make it easy to jump to the definitions of functions and
procedures in the current file with a pop-up selection.  To bind
@file{Imenu} to a mouse-press, use in your @file{.emacs}:

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

@cindex @file{Speedbar}, Emacs package

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

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

@multitable @columnfractions .15 .85
@item @kbd{C-M-a}
@tab Beginning of subprogram
@item @kbd{C-M-e}
@tab End of subprogram
@item @kbd{C-c @{}
@tab Beginning of block (stay inside the block)
@item @kbd{C-c @}}
@tab End of block (stay inside the block)
@item @kbd{C-M-n}
@tab Forward block (on same level)
@item @kbd{C-M-p}
@tab Backward block (on same level)
@item @kbd{C-M-d}
@tab Down block (enters a block)
@item @kbd{C-M-u}
@tab Backward up block (leaves a block)
@item @kbd{C-c C-n}
@tab Next Statement
@end multitable


@node Misc Options,  , Motion Commands, The IDLWAVE Major Mode
@section Miscellaneous Options
@cindex Hooks

@defopt idlwave-help-application
The external application providing reference help for programming.
@end defopt

@defopt idlwave-startup-message (@code{t})
Non-@code{nil} means display a startup message when @code{idlwave-mode}'
is first called.
@end defopt

@defopt idlwave-mode-hook
Normal hook.  Executed when a buffer is put into @code{idlwave-mode}.
@end defopt

@defopt idlwave-load-hook
Normal hook.  Executed when @file{idlwave.el} is loaded.
@end defopt

@node The IDLWAVE Shell, Installation, The IDLWAVE Major Mode, Top
@chapter The IDLWAVE Shell
@cindex IDLWAVE shell
@cindex Major mode, @code{idlwave-shell-mode}
@cindex IDL, as Emacs subprocess
@cindex Subprocess of Emacs, IDL
@cindex Comint, Emacs package
@cindex Windows
@cindex MacOS

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 @file{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 MacOSX.

@menu
* Starting the Shell::          How to launch IDL as a subprocess
* Using the Shell::             Interactively working with the Shell
* Multi-Line Commands::         
* Commands Sent to the Shell::  
* Debugging IDL Programs::      
* Examining Variables::         
* Custom Expression Examination::  
@end menu

@node Starting the Shell, Using the Shell, The IDLWAVE Shell, The IDLWAVE Shell
@section Starting the Shell
@cindex Starting the shell
@cindex Shell, starting
@cindex Dedicated frame, for shell buffer
@cindex Frame, for shell buffer
@cindex Subprocess of Emacs, IDL

@kindex C-c C-s
The IDLWAVE shell can be started with the command @kbd{M-x
idlwave-shell}.  In @code{idlwave-mode} the function is bound to
@kbd{C-c C-s}.  It creates a buffer @file{*idl*} which is used to
interact with the shell.  If the shell is already running, @kbd{C-c C-s}
will simply switch to the shell buffer.  The command @kbd{C-c C-l}
(@code{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 @code{idlwave-shell-automatic-start} to @code{t}.

In order to create a separate frame for the IDLWAVE shell buffer, call
@code{idlwave-shell} with a prefix argument: @kbd{C-u C-c C-s} or
@kbd{C-u C-c C-l}.  Two prefix argument (@kbd{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
@code{idlwave-shell-use-dedicated-frame}.  If you'd prefer the shell
window to appear in the same frame, but at a reduced height, configure
@code{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:

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

Replace the @samp{-geometry 80x32} option with @samp{-nw} if you prefer
the Emacs process to run directly inside the terminal window.

@cindex ENVI
@cindex IDL> Prompt

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

@defopt idlwave-shell-explicit-file-name (@file{idl})
This is the command to run IDL.
@end defopt

@defopt idlwave-shell-command-line-options
A list of command line options for calling the IDL program.
@end defopt

@defopt idlwave-shell-prompt-pattern
Regexp to match IDL prompt at beginning of a line.
@end defopt

@defopt idlwave-shell-process-name
Name to be associated with the IDL process.
@end defopt

@defopt idlwave-shell-automatic-start  (@code{nil})
Non-@code{nil} means attempt to invoke idlwave-shell if not already
running.
@end defopt

@defopt idlwave-shell-initial-commands
Initial commands, separated by newlines, to send to IDL.
@end defopt

@defopt idlwave-shell-save-command-history (@code{t})
Non-@code{nil} means preserve command history between sessions.
@end defopt

@defopt idlwave-shell-command-history-file (@file{~/.idlwave/.idlwhist})
The file in which the command history of the idlwave shell is saved.
Unless it's an absolute path, it goes in
@code{idlwave-config-directory}.
@end defopt
  
@defopt idlwave-shell-use-dedicated-frame (@code{nil})
Non-@code{nil} means IDLWAVE should use a special frame to display the
shell buffer.
@end defopt

@defopt idlwave-shell-buffer-height-frac  (@code{nil})
Non-@code{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 @code{idlwave-shell-use-dedicated-frame}
is @code{nil}.
@end defopt

@defopt idlwave-shell-use-dedicated-window (@code{nil})
Non-@code{nil} means use a dedicated window for the shell, taking care
not it replace it with other buffers.
@end defopt

@defopt idlwave-shell-frame-parameters
The frame parameters for a dedicated idlwave-shell frame.
@end defopt

@defopt idlwave-shell-raise-frame (@code{t})
Non-@code{nil} means `idlwave-shell' raises the frame showing the shell
window.
@end defopt

@defopt idlwave-shell-temp-pro-prefix
The prefix for temporary IDL files used when compiling regions.
@end defopt

@cindex Hooks
@defopt idlwave-shell-mode-hook
Hook for customizing @code{idlwave-shell-mode}.
@end defopt

@node Using the Shell, Multi-Line Commands, Starting the Shell, The IDLWAVE Shell
@section Using the Shell
@cindex Comint
@cindex Shell, basic commands
@cindex History, 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 @key{UP} and @key{DOWN} arrows cycle through the input
history just like in an X terminal@footnote{This is different from
normal Emacs/Comint behavior, but more like an xterm.  If you prefer the
default comint functionality, check the variable
@code{idlwave-shell-arrows-do-history}.}.  The history is preserved
between emacs and IDL sessions.  Here is a list of commonly used
commands:

@multitable @columnfractions .12 .88
@item @key{UP}, @key{M-p}
@tab Cycle backwards in input history
@item @key{DOWN}, @key{M-n}
@tab Cycle forwards in input history
@item @kbd{M-r}
@tab Previous input matching a regexp
@item @kbd{M-s}
@tab Next input matching a regexp
@item @kbd{return}
@tab Send input or copy line to current prompt
@item @kbd{C-c C-a}
@tab Beginning of line; skip prompt
@item @kbd{C-c C-u}
@tab Kill input to beginning of line
@item @kbd{C-c C-w}
@tab Kill word before cursor
@item @kbd{C-c C-c}
@tab Send ^C
@item @kbd{C-c C-z}
@tab Send ^Z
@item @kbd{C-c C-\}
@tab Send ^\
@item @kbd{C-c C-o}
@tab Delete last batch of process output
@item @kbd{C-c C-r}
@tab Show last batch of process output
@item @kbd{C-c C-l}
@tab List input history
@end multitable

In addition to these standard @file{comint} commands,
@code{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 @ref{Routine Info} and
@ref{Online Help} and @ref{Completion} for more information on these
commands.

@cindex Completion, in the shell
@cindex Routine info, in the shell
@cindex Online Help, in the shell
@multitable @columnfractions .12 .88
@item @kbd{@key{TAB}}
@tab  Completion of file names (between quotes and after executive
commands @samp{.run} and @samp{.compile}), routine names, class names,
keywords, system variables, system variable tags etc.
(@code{idlwave-shell-complete}).
@item @kbd{M-@key{TAB}}
@tab Same as @key{TAB}
@item @kbd{C-c ?}
@tab Routine Info display (@code{idlwave-routine-info})
@item @kbd{M-?}
@tab IDL online help on routine (@code{idlwave-routine-info-from-idlhelp})
@item @kbd{C-c C-i}
@tab Update routine info from buffers and shell
(@code{idlwave-update-routine-info})
@item @kbd{C-c C-v}
@tab Find the source file of a routine (@code{idlwave-find-module})
@item @kbd{C-c C-t}
@tab Find the source file of a routine in the currently visited file 
(@code{idlwave-find-module-this-file}).
@item @kbd{C-c =}
@tab Compile a library routine (@code{idlwave-resolve})
@end multitable

@defopt idlwave-shell-arrows-do-history (@code{t})
Non-@code{nil} means @key{UP} and @key{DOWN} arrows move through command
history like xterm.
@end defopt

@defopt idlwave-shell-comint-settings
Alist of special settings for the comint variables in the IDLWAVE Shell.
@end defopt

@defopt idlwave-shell-file-name-chars
The characters allowed in file names, as a string.  Used for file name
completion.
@end defopt

@defopt idlwave-shell-graphics-window-size
Size of IDL graphics windows popped up by special IDLWAVE command.
@end defopt

@cindex Input mode
@cindex Character input mode (Shell)
@cindex Line input mode (Shell)
@cindex Magic spells, for input mode
@cindex Spells, magic
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 @key{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 @code{GET_KBRD} function.  You can send a single character to
IDL with the command @kbd{C-c C-x} (@code{idlwave-shell-send-char}).
When you press @kbd{C-c C-y} (@code{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 @kbd{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.

@defopt idlwave-shell-use-input-mode-magic (@code{nil})
Non-@code{nil} means IDLWAVE should check for input mode spells in
output.
@end defopt

@defopt idlwave-shell-input-mode-spells
The three regular expressions which match the ``magic spells'' for input
modes.
@end defopt

@node Multi-Line Commands, Commands Sent to the Shell, Using the Shell, The IDLWAVE Shell
@section Multi-Line Commands
@cindex Multi-line commands
@cindex Commands, multi-line


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
@samp{pro} or @samp{function} routine definition statement, but with an
@samp{END}) can be compiled, or a batch routine or selected region can
be run (@pxref{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 @key{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., @kbd{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. @code{FOR...BEGIN..ENDFOR}).  To group multi-line control or other
statement together as a single command, use an @samp{&} at the end of
each line, e.g.:

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

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

@example
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)'
@end example

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

@node Commands Sent to the Shell, Debugging IDL Programs, Multi-Line Commands, The IDLWAVE Shell
@section Commands Sent to the Shell
@cindex Commands in shell, showing
@cindex Showing commands in shell

The IDLWAVE buffers and shell interact very closely.  In addition to the
normal commands you enter at the @code{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 @code{breakpoint}, @code{.step} and other
debug commands (@pxref{Debugging IDL Programs}), @code{.run} and other
compilation statements (@pxref{Compiling Programs}), examination
commands like @code{print} and @code{help} (@pxref{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
@code{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 @emph{examine} commands, see @ref{Examining
Variables}.

@defopt idlwave-shell-show-commands (@code{'(run misc breakpoint)})
A list of command types to echo in the shell when sent.  Possible values
are @code{run} for @code{.run}, @code{.compile} and other run commands,
@code{misc} for lesser used commands like @code{window},
@code{retall},@code{close}, etc., @code{breakpoint} for breakpoint
setting and clearing commands, and @code{debug} for other debug,
stepping, and continue commands.  In addition, if the variable is set to
the single symbol @code{'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 @code{print} command).
As a special case, any error message in the output will be displayed
(e.g., stepping to an error).
@end defopt

@node Debugging IDL Programs, Examining Variables, Commands Sent to the Shell, The IDLWAVE Shell
@section Debugging IDL Programs
@cindex Debugging
@cindex Keybindings for debugging
@cindex Toolbar

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 @code{breakpoint}, @code{.step},
@code{.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
@kbd{C-c C-d C-t} (@code{idlwave-shell-toggle-toolbar}).


@defopt idlwave-shell-use-toolbar (@code{t})
Non-@code{nil} means use the debugging toolbar in all IDL related
buffers.
@end defopt

@menu
* A Tale of Two Modes::         
* Debug Key Bindings::          
* Breakpoints and Stepping::    
* Compiling Programs::          
* Walking the Calling Stack::   
* Electric Debug Mode::         
@end menu


@node A Tale of Two Modes, Debug Key Bindings, Debugging IDL Programs, Debugging IDL Programs
@subsection A Tale of Two Modes
@cindex Electric Debug Mode
@cindex Debugging Interface

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.  @xref{Electric Debug
Mode}, for more on that mode.  Note that electric debug mode can be
prevented from activating automatically by customizing the variable
@code{idlwave-shell-automatic-electric-debug}.

@node Debug Key Bindings, Breakpoints and Stepping, A Tale of Two Modes, Debugging IDL Programs
@subsection Debug Key Bindings
@kindex C-c C-d
@cindex Key bindings

The standard debugging key bindings are always available by default on
the prefix key @kbd{C-c C-d}, so, for example, setting a breakpoint is
done with @kbd{C-c C-d C-b}, and compiling a source file with @kbd{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
@kbd{C-c C-d} (though these bindings will typically also be available
--- see @code{idlwave-shell-activate-prefix-keybindings}).  For
example, if you include in @file{.emacs}:

@lisp
(setq idlwave-shell-debug-modifiers '(control shift))
@end lisp

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

@defopt idlwave-shell-prefix-key (@kbd{C-c C-d})
The prefix key for the debugging map
@code{idlwave-shell-mode-prefix-map}.
@end defopt

@defopt idlwave-shell-activate-prefix-keybindings (@code{t})
Non-@code{nil} means debug commands will be bound to the prefix
key, like @kbd{C-c C-d C-b}.
@end defopt

@defopt idlwave-shell-debug-modifiers (@code{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 @code{control}, @code{meta}, @code{super}, @code{hyper},
@code{alt}, and @code{shift}.
@end defopt

@node Breakpoints and Stepping, Compiling Programs, Debug Key Bindings, Debugging IDL Programs
@subsection Breakpoints and Stepping
@cindex Breakpoints
@cindex Stepping
@cindex Execution, controlled

@kindex C-c C-d C-b
@kindex C-c C-d C-b
IDLWAVE helps you set breakpoints and step through code.  Setting a
breakpoint in the current line of the source buffer is accomplished
with @kbd{C-c C-d C-b} (@code{idlwave-shell-break-here}).  With a
prefix arg of 1 (i.e. @kbd{C-1 C-c C-d C-b}), the breakpoint gets a
@code{/ONCE} keyword, meaning that it will be deleted after first use.
With a numeric prefix greater than one (e.g. @kbd{C-4 C-c C-d C-b}),
the breakpoint will only be active the @code{nth} time it is hit.
With a single non-numeric prefix (i.e. @kbd{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 @kbd{C-c C-d C-d} (@code{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 @kbd{C-c C-d
C-a} (@code{idlwave-clear-all-bp}).  Breakpoints can also be disabled
and re-enabled: @kbd{C-c C-d C-\}
(@code{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 @emph{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 @kbd{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.  @kbd{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 @kbd{C-c C-d C-s} to execute one
line of IDL code ("step into"); @kbd{C-c C-d C-n} to step a single line,
treating procedure and function calls as a single step ("step over");
@kbd{C-c C-d C-h} to continue execution to the line at the cursor and
@kbd{C-c C-d C-r} to continue execution.  @xref{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:

@multitable @columnfractions .23 .77
@item @kbd{C-c C-d C-b}
@tab Set breakpoint (@code{idlwave-shell-break-here})
@item @kbd{C-c C-d C-i}
@tab Set breakpoint in module named here (@code{idlwave-shell-break-in})
@item @kbd{C-c C-d C-d}
@tab Clear current breakpoint (@code{idlwave-shell-clear-current-bp})
@item @kbd{C-c C-d C-a}
@tab Clear all breakpoints (@code{idlwave-shell-clear-all-bp})
@item @kbd{C-c C-d [}
@tab Go to the previous breakpoint (@code{idlwave-shell-goto-previous-bp})
@item @kbd{C-c C-d ]}
@tab Go to the next breakpoint (@code{idlwave-shell-goto-next-bp})
@item @kbd{C-c C-d C-\}
@tab Disable/Enable current breakpoint (@code{idlwave-shell-toggle-enable-current-bp})
@item @kbd{C-c C-d C-j}
@tab Set a breakpoint at the beginning of the enclosing routine.
@item @kbd{C-c C-d C-s}
@tab Step, into function calls (@code{idlwave-shell-step})
@item @kbd{C-c C-d C-n}
@tab Step, over function calls (@code{idlwave-shell-stepover})
@item @kbd{C-c C-d C-k}
@tab Skip one statement (@code{idlwave-shell-skip})
@item @kbd{C-c C-d C-u}
@tab Continue to end of block (@code{idlwave-shell-up})
@item @kbd{C-c C-d C-m}
@tab Continue to end of function (@code{idlwave-shell-return})
@item @kbd{C-c C-d C-o}
@tab Continue past end of function (@code{idlwave-shell-out})
@item @kbd{C-c C-d C-h}
@tab Continue to line at cursor position (@code{idlwave-shell-to-here})
@item @kbd{C-c C-d C-r}
@tab Continue execution to next breakpoint, if any (@code{idlwave-shell-cont})
@item @kbd{C-c C-d C-up}
@tab Show higher level in calling stack (@code{idlwave-shell-stack-up})
@item @kbd{C-c C-d C-down}
@tab Show lower level in calling stack (@code{idlwave-shell-stack-down})
@end multitable

All of these commands have equivalents in Electric Debug Mode, which
provides faster single-key access (@pxref{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 @code{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.

@defopt idlwave-shell-mark-breakpoints (@code{t})
Non-@code{nil} means mark breakpoints in the source file buffers.  The
value indicates the preferred method.  Valid values are @code{nil},
@code{t}, @code{face}, and @code{glyph}.
@end defopt

@defopt idlwave-shell-breakpoint-face
The face for breakpoint lines in the source code if
@code{idlwave-shell-mark-breakpoints} has the value @code{face}.
@end defopt

@defopt idlwave-shell-breakpoint-popup-menu (@code{t})
Whether to pop-up a menu and present a tooltip description on
breakpoint lines.
@end defopt

@defopt idlwave-shell-mark-stop-line (@code{t})
Non-@code{nil} means mark the source code line where IDL is currently
stopped.  The value specifies the preferred method.  Valid values are
@code{nil}, @code{t}, @code{arrow}, and @code{face}.
@end defopt

@defopt idlwave-shell-overlay-arrow (@code{">"})
The overlay arrow to display at source lines where execution halts, if
configured in @code{idlwave-shell-mark-stop-line}.
@end defopt

@defopt idlwave-shell-stop-line-face
The face which highlights the source line where IDL is stopped, if
configured in @code{idlwave-shell-mark-stop-line}.
@end defopt


@node Compiling Programs, Walking the Calling Stack, Breakpoints and Stepping, Debugging IDL Programs
@subsection Compiling Programs
@cindex Compiling programs
@cindex Programs, compiling
@cindex Default command line, executing
@cindex Executing a default command line

@kindex C-c C-d C-c
In order to compile the current buffer under the IDLWAVE shell, press
@kbd{C-c C-d C-c} (@code{idlwave-save-and-run}).  This first saves the
current buffer and then sends the command @samp{.run path/to/file} to the 
shell.  You can also execute @kbd{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
@kbd{C-c C-d C-y} (@code{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 @code{idlwave-shell-execute-default-command-line} with
a prefix argument: @kbd{C-u C-c C-d C-y}.  If you give two prefix
arguments, the last command on the @code{comint} input history is sent.

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

@node Walking the Calling Stack, Electric Debug Mode, Compiling Programs, Debugging IDL Programs
@subsection Walking the Calling Stack
@cindex Calling stack, walking

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 @kbd{C-c C-d C-@key{UP}}
(@code{idlwave-shell-stack-up}) and @kbd{C-c C-d C-@key{DOWN}}
(@code{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 @samp{[-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. @xref{Examining Variables},
for information how to examine the value of variables and expressions on
higher calling stack levels.

@html
<A NAME="EDEBUG"></A>
@end html
@node Electric Debug Mode,  , Walking the Calling Stack, Debugging IDL Programs
@subsection Electric Debug Mode
@cindex Electric Debug Mode
@cindex @samp{*Debugging*}

Even with a convenient debug key prefix enabled, repetitive stepping,
variable examination (@pxref{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 @emph{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 @samp{*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 @kbd{C-?}) are:

@multitable @columnfractions .2 .8
@item @kbd{a}
@tab Clear all breakpoints (@code{idlwave-shell-clear-all-bp})
@item @kbd{b}
@tab Set breakpoint, @kbd{C-u b} for a conditional break, @kbd{C-n b} for nth hit (@code{idlwave-shell-break-here})
@item @kbd{d}
@tab Clear current breakpoint (@code{idlwave-shell-clear-current-bp})
@item @kbd{e}
@tab Prompt for expression to print (@code{idlwave-shell-clear-current-bp}).
@item @kbd{h}
@tab Continue to the line at cursor position (@code{idlwave-shell-to-here})
@item @kbd{i}
@tab Set breakpoint in module named here (@code{idlwave-shell-break-in})
@item @kbd{[}
@tab Go to the previous breakpoint in the file (@code{idlwave-shell-goto-previous-bp})
@item @kbd{]}
@tab Go to the next breakpoint in the file
(@code{idlwave-shell-goto-next-bp})
@item @kbd{\}
@tab Disable/Enable current breakpoint (@code{idlwave-shell-toggle-enable-current-bp})
@item @kbd{j}
@tab Set breakpoint at beginning of enclosing routine (@code{idlwave-shell-break-this-module})
@item @kbd{k}
@tab Skip one statement (@code{idlwave-shell-skip})
@item @kbd{m}
@tab Continue to end of function (@code{idlwave-shell-return})
@item @kbd{n}
@tab Step, over function calls (@code{idlwave-shell-stepover})
@item @kbd{o}
@tab Continue past end of function (@code{idlwave-shell-out})
@item @kbd{p}
@tab Print expression near point or in region with @kbd{C-u p} (@code{idlwave-shell-print})
@item @kbd{q}
@tab End the debugging session and return to the Shell's main level
(@code{idlwave-shell-retall})
@item @kbd{r}
@tab Continue execution to next breakpoint, if any (@code{idlwave-shell-cont})
@item @kbd{s} or @kbd{@key{SPACE}}
@tab Step, into function calls (@code{idlwave-shell-step})
@item @kbd{t}
@tab Print a calling-level traceback in the shell
@item @kbd{u}
@tab Continue to end of block (@code{idlwave-shell-up})
@item @kbd{v}
@tab Turn Electric Debug Mode off
(@code{idlwave-shell-electric-debug-mode})
@item @kbd{x}
@tab Examine expression near point (or in region with @kbd{C-u x})
with shortcut of examine type.
@item @kbd{z}
@tab Reset IDL (@code{idlwave-shell-reset})
@item @kbd{+} or @kbd{=}
@tab Show higher level in calling stack (@code{idlwave-shell-stack-up})
@item @kbd{-} or @kbd{_}
@tab Show lower level in calling stack (@code{idlwave-shell-stack-down})
@item @kbd{?}
@tab Help on expression near point or in region with @kbd{C-u ?}
(@code{idlwave-shell-help-expression})
@item @kbd{C-?}
@tab Show help on the commands available.
@end multitable

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. @kbd{e},@kbd{t},@kbd{q},@kbd{x}).
Some have additional convenience bindings (like @kbd{@key{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, @kbd{C-u b} sets a conditional breakpoint, just
as it did with @kbd{C-u C-c C-d C-b}.

You can toggle the electric debug mode at any time in a buffer using
@kbd{C-c C-d C-v} (@kbd{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 @kbd{q} (@code{idlwave-shell-retall}).
This disables electric debug mode in all IDLWAVE buffers@footnote{Note
that this binding is not symmetric: @kbd{C-c C-d C-q} is bound to
@code{idlwave-shell-quit}, which quits your IDL session.}.  Help is
available for the command shortcuts with @kbd{C-?}.  If you find this
mode gets in your way, you can keep it from automatically activating
by setting the variable @code{idlwave-shell-automatic-electric-debug}
to @code{nil}, or @code{'breakpoint}.  If you'd like the convenient
electric debug shortcuts available also when run-time errors are
encountered, set to @code{t}.

@defopt idlwave-shell-automatic-electric-debug (@code{'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 @code{nil} for never, and
@code{t} for both breakpoints and errors, this can be
@code{'breakpoint} (the default) to enable it only at breakpoint
halts.
@end defopt

@defopt idlwave-shell-electric-stop-color (Violet)
Default color of the stopped line overlay when in electric debug mode.
@end defopt        

@defopt idlwave-shell-electric-stop-line-face 
The face to use for the stopped line.  Defaults to a face similar to the
modeline, with color @code{idlwave-shell-electric-stop-color}.
@end defopt

@defopt idlwave-shell-electric-zap-to-file (@code{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.
@end defopt

@html
<A NAME="EXAMINE"></A>
@end html
@node Examining Variables, Custom Expression Examination, Debugging IDL Programs, The IDLWAVE Shell
@section Examining Variables
@cindex @code{PRINT} expressions
@cindex @code{HELP}, on expressions
@cindex Expressions, printing & help
@cindex Examining expressions
@cindex Printing expressions
@cindex Mouse binding to print expressions

@kindex C-c C-d C-p
Do you find yourself repeatedly typing, e.g. @code{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 @emph{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 @code{idlwave-shell-separate-examine-output} is
non-@code{nil} (the default), all examine output will be sent to a
special @file{*Examine*} buffer, rather than the shell.  The output of
prior examine commands is saved in this buffer.  In this buffer @key{c}
clears the contents, and @key{q} hides the buffer.

The two most basic examine commands are bound to @kbd{C-c C-d C-p}, to
print the expression at point, and @kbd{C-c C-d ?}, to invoke help on
this expression@footnote{Available as @kbd{p} and @kbd{?} in Electric
Debug Mode (@pxref{Electric Debug Mode})}.  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 (@kbd{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
@code{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
@kbd{S-Mouse-2} to print an expression and @kbd{C-M-Mouse-2} to invoke
help (i.e. you need to hold down @key{META} and @key{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 @emph{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, @xref{Custom Expression Examination}.

@cindex Printing expressions, on calling stack
@cindex Restrictions for expression printing
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
(@pxref{Walking the Calling Stack}, for information on stepping back
through the calling stack).  The following restrictions apply for all
levels except the current:

@itemize @bullet
@item
Array expressions must use the @samp{[ ]} index delimiters.  Identifiers
with a @samp{( )} will be interpreted as function calls.
@item
@cindex ROUTINE_NAMES, IDL procedure
N.B.: printing values of expressions on higher levels of the calling
stack uses the @emph{unsupported} IDL routine @code{ROUTINE_NAMES},
which may or may not be available in future versions of IDL.  Caveat
Examinor.
@end itemize

@defopt idlwave-shell-expression-face
The face for @code{idlwave-shell-expression-overlay}.
Allows you to choose the font, color and other properties for
the expression printed by IDL.
@end defopt

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

@defopt idlwave-shell-separate-examine-output (@code{t})
If non-@code{nil}, re-direct the output of examine commands to a special
@file{*Examine*} buffer, instead of in the shell itself. 
@end defopt

@defopt idlwave-shell-max-print-length (200)
The maximum number of leading array entries to print, when examining
array expressions.
@end defopt

@node Custom Expression Examination,  , Examining Variables, The IDLWAVE Shell
@section Custom Expression Examination
@cindex Expressions, custom examination
@cindex Custom expression examination

The variety of possible variable and expression examination commands is
endless (just look, for instance, at the keyword list to
@code{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 @kbd{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 @code{idlwave-shell-examine-alist}
variable@footnote{In Electric Debug Mode (@pxref{Electric Debug
Mode}), the key @kbd{x} provides a single-character shortcut interface
to the same examine functions for the expression at point or marked by
the region.}.  This variable is a list of key-value pairs (an
@emph{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 @code{___} (three underscores) will be
replaced by the selected expression before being sent to the shell.
An example might be key @code{Structure Help} with value
@code{help,___,/STRUCTURE}.  In that case, you'd be prompted with
@emph{Structure Help}, which might send something like
@code{help,var,/STRUCTURE} to the shell for output.
@code{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
@code{idlwave-shell-examine} and @code{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
@code{idlwave-shell-examine-alist} values, e.g.:

@lisp
(add-hook 'idlwave-shell-mode-hook
          (lambda ()
            (idlwave-shell-define-key-both [s-down-mouse-2] 
                                 (idlwave-shell-mouse-examine 
                                  "print, size(___,/DIMENSIONS)"))
            (idlwave-shell-define-key-both [f9] (idlwave-shell-examine
                                       "print, size(___,/DIMENSIONS)"))
            (idlwave-shell-define-key-both [f10] (idlwave-shell-examine 
                                        "print,size(___,/TNAME)"))
            (idlwave-shell-define-key-both [f11] (idlwave-shell-examine
                                        "help,___,/STRUCTURE"))))
@end lisp                                        
            
@noindent Now pressing @key{f9}, or middle-mouse dragging with the
@key{SUPER} key depressed, will print the dimensions of the nearby or
highlighted expression.  Pressing @key{f10} will give the type string,
and @key{f11} will show the contents of a nearby structure.  As you can
see, the possibilities are only marginally finite.

@defopt 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 @code{___}
(three underscores) are replaced by the indicated expression.
@end defopt

@node Installation, Acknowledgements, The IDLWAVE Shell, Top
@chapter Installation
@cindex Installation

@menu
* Installing IDLWAVE::          How to install the distribution
* Installing Online Help::      Where to get the additional files needed
@end menu

@node Installing IDLWAVE, Installing Online Help, Installation, Installation
@section Installing IDLWAVE

@cindex FTP site
@cindex URL, homepage for IDLWAVE
@cindex Homepage for IDLWAVE
@cindex IDLWAVE, homepage
@cindex XEmacs package IDLWAVE
@cindex Emacs, distributed with IDLWAVE
IDLWAVE is part of Emacs 21.1 and later.  It is also an XEmacs package
and can be installed from
@uref{ftp://ftp.xemacs.org/pub/xemacs/packages/,the XEmacs ftp site}
with the normal package management system on XEmacs 21.  You can also
download IDLWAVE and install it yourself from
@uref{@value{IDLWAVEHOMEPAGE}, the maintainers webpage}.  Follow the
instructions in the INSTALL file.

@node Installing Online Help,  , Installing IDLWAVE, Installation
@section Installing Online Help
@cindex Installing online help
@cindex Online Help, Installation

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 @uref{@value{IDLWAVEHOMEPAGE}, the
maintainers webpage}.  You need to place the files somewhere on your
system and tell IDLWAVE where they are with:

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

@noindent The default location is @file{/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.

@node Acknowledgements, Sources of Routine Info, Installation, Top
@chapter Acknowledgements
@cindex Acknowledgements
@cindex Maintainer, of IDLWAVE
@cindex Authors, of IDLWAVE
@cindex Contributors, to IDLWAVE
@cindex Email address, of Maintainer
@cindex Thanks

@noindent
The main contributors to the IDLWAVE package have been:

@itemize @minus
@item
@uref{mailto:chase@@att.com, @b{Chris Chase}}, the original author.
Chris wrote @file{idl.el} and @file{idl-shell.el} and maintained them
for several years.

@item
@uref{mailto:dominik@@astro.uva.nl, @b{Carsten Dominik}} was in charge
of the package from version 3.0, during which time he overhauled almost
everything, modernized IDLWAVE with many new features, and developed the
manual.

@item 
@uref{mailto:jdsmith@@as.arizona.edu, @b{J.D. Smith}}, the current
maintainer, as of version 4.10, helped shape object method completion
and most new features introduced in versions 4.x, and introduced many
new features for IDLWAVE versions 5.x and 6.x.
@end itemize

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

@itemize @minus
@item
Ulrik Dickow <dickow__at__nbi.dk>
@item
Eric E. Dors <edors__at__lanl.gov>
@item
Stein Vidar H. Haugan <s.v.h.haugan__at__astro.uio.no>
@item
David Huenemoerder <dph__at__space.mit.edu>
@item
Kevin Ivory <Kevin.Ivory__at__linmpi.mpg.de>
@item
Dick Jackson <dick__at__d-jackson.com>
@item
Xuyong Liu <liu__at__stsci.edu>
@item
Simon Marshall <Simon.Marshall__at__esrin.esa.it>
@item
Craig Markwardt <craigm__at__cow.physics.wisc.edu>
@item
Laurent Mugnier <mugnier__at__onera.fr>
@item
Lubos Pochman <lubos__at__rsinc.com>
@item
Bob Portmann <portmann__at__al.noaa.gov>
@item
Patrick M. Ryan <pat__at__jaameri.gsfc.nasa.gov>
@item
Marty Ryba <ryba__at__ll.mit.edu>
@item
Phil Williams <williams__at__irc.chmcc.org>
@item
Phil Sterne <sterne__at__dublin.llnl.gov>
@item
Paul Sorenson <aardvark62__at__msn.com>
@end itemize

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.

@noindent
Thanks to everyone!

@node Sources of Routine Info, HTML Help Browser Tips, Acknowledgements, Top
@appendix Sources of Routine Info

@cindex Sources of routine information
In @ref{Routine Info} and @ref{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.

@menu
* Routine Definitions::         Where IDL Routines are defined.
* Routine Information Sources::  So how does IDLWAVE know about...
* Catalogs::                    
* Load-Path Shadows::           Routines defined in several places
* Documentation Scan::          Scanning the IDL Manuals
@end menu

@node Routine Definitions, Routine Information Sources, Sources of Routine Info, Sources of Routine Info
@appendixsec Routine Definitions
@cindex Routine definitions
@cindex IDL variable @code{!PATH}
@cindex @code{!PATH}, IDL variable
@cindex @code{CALL_EXTERNAL}, IDL routine
@cindex @code{LINKIMAGE}, IDL routine
@cindex External routines

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

@enumerate
@item 
@emph{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.
@item
Routines which are @emph{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.
@item 
@emph{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 @emph{system routines} distributed with IDL,
and usually available in the @file{lib} subdirectory of the IDL
distribution.
@item
External routines written in other languages (like Fortran or C) can be
called with @code{CALL_EXTERNAL}, linked into IDL via @code{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).
@end enumerate

@node Routine Information Sources, Catalogs, Routine Definitions, Sources of Routine Info
@appendixsec Routine Information Sources
@cindex Routine info sources
@cindex Builtin list of routines
@cindex Updating routine info
@cindex Scanning buffers for routine info
@cindex Buffers, scanning for routine info
@cindex Shell, querying for routine info

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

@enumerate

@item
It has a @emph{builtin list} with information about the routines IDL
ships with.  IDLWAVE @value{VERSION} is distributed with a list of
@value{NSYSROUTINES} routines and object methods, reflecting IDL version
@value{IDLVERSION}.  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 by scanning the IDL manuals to produce
the file @file{idlw-rinfo.el}.

@item 
IDLWAVE @emph{scans} all its @emph{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 @kbd{C-c C-i} (@code{idlwave-update-routine-info}) can be used
at any time to rescan all buffers.

@item
If you have an IDLWAVE-Shell running in the Emacs session, IDLWAVE will
@emph{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
@kbd{C-c C-d C-c}, the routine info for that file is queried.  Though
rarely necessary, the command @kbd{C-c C-i}
(@code{idlwave-update-routine-info}) can be used to explicitly update
the shell routine data.

@item
Many popular libraries are distributed with routine information already
scanned into @emph{library catalogs} (@pxref{Library Catalogs}).  These
per-directory catalog files can also be built by the user with the
supplied @file{idlwave_catalog} tool.  They are automatically discovered
by IDLWAVE.

@item
IDLWAVE can scan selected directories of source files and store the
result in a single @emph{user catalog} file which will be
automatically loaded just like @file{idlw-rinfo.el}. @xref{User
Catalog}, for information on how to scan files in this way.
@end enumerate

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 @code{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.

@defopt idlwave-init-rinfo-when-idle-after (@code{10})
Seconds of idle time before routine info is automatically initialized.
@end defopt

@defopt idlwave-scan-all-buffers-for-routine-info (@code{t})
Non-@code{nil} means scan all buffers for IDL programs when updating
info.
@end defopt

@defopt idlwave-query-shell-for-routine-info (@code{t})
Non-@code{nil} means query the shell for info about compiled routines.
@end defopt

@defopt idlwave-auto-routine-info-updates
Controls under what circumstances routine info is updated automatically.
@end defopt

@html
<A NAME="CATALOGS"></A>
@end html
@node Catalogs, Load-Path Shadows, Routine Information Sources, Sources of Routine Info
@appendixsec Catalogs
@cindex Catalogs

@emph{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 (@pxref{Routine Info}) to other source collections.

Starting with version 5.0, there are two types of catalogs available
with IDLWAVE.  The traditional @emph{user catalog} and the newer
@emph{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 @code{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
@code{idlwave-library-path} to allow library catalogs to be located, and
to setup directories for user catalog scan (@pxref{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 @code{idlwave-path-file} (@file{~/.idlwave/idlpath.el}, by
default).  If @code{idlwave-auto-write-path} is enabled (which is the
default), the paths are written out whenever the IDLWAVE shell is
started.

@defopt idlwave-auto-write-path  (@code{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.
@end defopt

@defopt idlwave-library-path
IDL library path for Windows and MacOS.  Under Unix/MacOSX, will be
obtained from the Shell when run.
@end defopt

@defopt 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/MacOSX, will be obtained from the Shell and recorded, if run.
@end defopt

@defopt idlwave-config-directory (@file{~/.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).
@end defopt

@menu
* Library Catalogs::            
* User Catalog::                
@end menu

@html
<A NAME="LIBRARY_CATALOGS"></A>
@end html
@node Library Catalogs, User Catalog, Catalogs, Catalogs
@appendixsubsec Library Catalogs
@cindex @file{.idlwave_catalog}
@cindex Library catalogs
@cindex @code{idlwave_catalog}

Library catalogs consist of files named @file{.idlwave_catalog} stored
in directories containing @code{.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. @emph{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 @file{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:
@code{idlwave_catalog}.  It can be called quite simply:
@example
idlwave_catalog MyLib
@end example

@noindent This will scan all directories recursively beneath the current and
populate them with @file{.idlwave_catalog} files, tagging the routines
found there with the name library ``MyLib''.  The full usage
information:

@example
Usage: idlwave_catalog  [-l] [-v] [-d] [-s] [-f] [-h] libname
       libname - Unique name of the catalog (4 or more alphanumeric
                 characters).
            -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.
@end example

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

@defopt idlwave-use-library-catalogs  (@code{t})
Whether to search for and load library catalogs.  Disable if load
performance is a problem and/or the catalogs are not needed.
@end defopt

@node User Catalog,  , Library Catalogs, Catalogs
@appendixsubsec User Catalog
@cindex User catalog
@cindex IDL library routine info
@cindex Windows
@cindex MacOS
@cindex IDL variable @code{!DIR}
@cindex @code{!DIR}, IDL variable

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
(@file{.idlwave/idlusercat.el} by default).  Although library catalogs
are more flexible, there may be reasons to prefer a user catalog
instead, including:

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

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 and MacOS (not OSX), you need to specify the IDL search path in
the variable @code{idlwave-library-path}, and the location of the IDL
directory (the value of the @code{!DIR} system variable) in the variable
@code{idlwave-system-directory}, like this@footnote{The initial @samp{+}
leads to recursive expansion of the path, just like in IDL}:

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

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

The command @kbd{M-x idlwave-create-user-catalog-file} (or the menu item
@samp{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 @samp{[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 @w{@samp{[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
@code{idlwave-update-routine-info} with a double prefix argument:
@w{@kbd{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 @w{@kbd{C-u C-u C-u C-c C-i}}, updating will be done with a
background job@footnote{Unix systems only, I think.}.  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 (@pxref{Library
Catalogs}).

@defopt idlwave-special-lib-alist
Alist of regular expressions matching special library directories for
labeling in routine-info display.
@end defopt

@node Load-Path Shadows, Documentation Scan, Catalogs, Sources of Routine Info
@appendixsec Load-Path Shadows
@cindex Load-path shadows
@cindex Shadows, load-path
@cindex Duplicate routines
@cindex Multiply defined routines
@cindex Routine definitions, multiple
@cindex Application, testing for shadowing
@cindex Buffer, testing for shadowing

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
@file{*Shadows*}.  The format of the output is identical to the source
section of the routine info buffer (@pxref{Routine Info}).  The
different definitions of a routine are ordered by @emph{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 @kbd{C-c
C-i}.  Here are the different routines (also available in the Menu
@samp{IDLWAVE->Routine Info}):

@table @asis
@item @kbd{M-x idlwave-list-buffer-load-path-shadows}
This commands 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: @kbd{C-c C-b}
@item @kbd{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 @code{RESOLVE_ALL} to compile any routines used by
your code, update the routine info inside IDLWAVE with @kbd{C-c C-i} and
then check for shadowing.
@item @kbd{M-x idlwave-list-all-load-path-shadows}
This command checks all routines accessible to IDLWAVE for conflicts.
@end table

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
@file{/usr/local/rsi/idl/lib}) and any site specific or user specific
files.  Therefore, such local files should not be installed inside the
@file{lib} directory of the IDL directory.  This is also advisable for
many other reasons.

@cindex Windows
@cindex MacOS
@cindex IDL variable @code{!DIR}
@cindex @code{!DIR}, IDL variable
Users of Windows and MacOS (not X) also must set the variable
@code{idlwave-system-directory} to the value of the @code{!DIR} system
variable in IDL.  IDLWAVE appends @file{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 (@pxref{Routine Info}).

@node Documentation Scan,  , Load-Path Shadows, Sources of Routine Info
@appendixsec Documentation Scan 
@cindex @file{get_html_rinfo}
@cindex @file{idlw-rinfo.el}
@cindex Scanning the documentation
@cindex Perl program, to create @file{idlw-rinfo.el}

@strong{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 @file{get_html_rinfo}, and the
@file{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 @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 @uref{@value{IDLWAVEHOMEPAGE}, the maintainers webpage}.

The HTML files and related images can be produced from the
@file{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
@file{get_html_rinfo} which constructs the @file{idlw-rinfo.el} file by
scanning the HTML documents produced from the IDL documentation.
Instructions on how to use @file{get_html_rinfo} are in the program
itself.

@node HTML Help Browser Tips, Configuration Examples, Sources of Routine Info, Top
@appendix HTML Help Browser Tips
@cindex Browser Tips

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
@emph{IDL Assistant} is distributed with IDL.  If this help browser is
available, it is the preferred choice, and the default.  The variable
@code{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 a many different system types, a single browser
configuration is not possible, but choices abound.  On many systems,
the default browser configured in @code{browse-url-browser-function},
and hence inherited by default by
@code{idlwave-help-browser-function}, is Netscape.  Unfortunately, the
HTML manuals decompiled from the original source contain formatting
structures which Netscape 4.x does not handle well, though they are
still readable.  A much better choice is Mozilla, or one of the
Mozilla-derived browsers such as
@uref{http://galeon.sourceforge.net/,Galeon} (GNU/Linux),
@uref{http://www.mozilla.org/projects/camino/,Camino} (MacOSX), or
@uref{http://www.mozilla.org/projects/firebird/,Firebird} (all
platforms).  Newer versions of Emacs provide a browser-function choice
@code{browse-url-gnome-moz} which uses the Gnome-configured browser.

Note that the HTML files decompiled from the help sources contain
specific references to the @samp{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 @samp{Symbol} by following the directions
@uref{http://hutchinson.belmont.ma.us/tth/Xfonts.html, 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.).

@noindent Individual platform recommendations:

@itemize @bullet
@item Unix/MacOSX: The @uref{http://www.w3m.org,@code{w3m}} browser
and its associated
@uref{http://emacs-w3m.namazu.org/,@code{emacs-w3m}} emacs mode
provide in-buffer browsing with image display, and excellent speed and
formatting.  Both the Emacs mode and the browser itself must be
downloaded separately.  To use this browser, include

@lisp
(setq idlwave-help-browser-function 'w3m-browse-url)
@end lisp

in your @file{.emacs}.  Setting a few other nice @code{w3m} options
cuts down on screen clutter:

@lisp
(setq w3m-use-tab nil
      w3m-use-header-line nil
      w3m-use-toolbar nil)
@end lisp

If you use a dedicated frame for help, you might want to add the
following, to get consistent behavior with the @kbd{q} key:

@lisp
;; Close my help window when w3m closes.
(defadvice w3m-close-window (after idlwave-close activate)
  (if (boundp 'idlwave-help-frame)
      (idlwave-help-quit)))
@end lisp

Note that you can open the file in an external browser from within
@code{w3m} using @kbd{M}.
@end itemize

@node Configuration Examples, Windows and MacOS, HTML Help Browser Tips, Top
@appendix Configuration Examples
@cindex Configuration examples
@cindex Example configuration
@cindex @file{.emacs}
@cindex Default settings, of options
@cindex Interview, with the maintainer

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

@noindent
@b{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:

@itemize @minus
@item
are not self-evident (i.e. too magic) when used by an unsuspecting user.
@item
are too intrusive.
@item
will not work properly on all Emacs installations.
@item
break with widely used standards.
@item
use function or other non-standard keys.
@item
are purely personal customizations, like additional key bindings, and
library names.
@end itemize

@noindent To see what I mean, here is the @emph{entire} configuration
the old maintainer had in his @file{.emacs}:

@lisp
(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")))
@end lisp

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!

@example
;;; 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)
      (idlwave-help-quit)))

;; 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] 
                                 (idlwave-shell-mouse-examine 
                                  "print, size(___,/DIMENSIONS)"))
            (idlwave-shell-define-key-both [f9] (idlwave-shell-examine
                                       "print, size(___,/DIMENSIONS)"))
            (idlwave-shell-define-key-both [f10] (idlwave-shell-examine 
                                        "print,size(___,/TNAME)"))
            (idlwave-shell-define-key-both [f11] (idlwave-shell-examine
                                        "help,___,/STRUCTURE"))))
@end example

@html
<A NAME="WIN_MAC"></A>
@end html
@node Windows and MacOS, Troubleshooting, Configuration Examples, Top
@appendix Windows and MacOS
@cindex Windows
@cindex MacOS
@cindex MacOSX

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 or NTXEmacs) or MacOS.

The only real problem is that there is no command-line version of IDL
for Windows or MacOS(<=9) 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 @file{.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
@w{@samp{C:\Program Files\IDLWAVE}} and that IDL is installed in
@w{@samp{C:\RSI\IDL63}}.

@lisp
;; 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/")

@end lisp

@noindent Furthermore, Windows sometimes tries to outsmart you --- make
sure you check the following things:

@itemize @bullet
@item When you download the IDLWAVE distribution, make sure you save the 
file under the names @file{idlwave.tar.gz}.
@item M-TAB switches among running programs --- use Esc-TAB
instead.
@item Other issues as yet unnamed...
@end itemize

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.
@xref{Help with HTML Documentation}.

@html
<A NAME="TROUBLE"></A>
@end html
@node Troubleshooting, GNU Free Documentation License, Windows and MacOS, Top
@appendix Troubleshooting
@cindex Troubleshooting

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

@enumerate

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

@item @strong{I get errors like @samp{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 @samp{idl}, which
presumes such an executable is on your search path.  You need to
ensure @samp{idl} is on your @samp{$PATH}, or specify the full
pathname to the idl program with the variable
@code{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 MacOSX; see the next topic.

@item @strong{IDLWAVE is disregarding my @samp{IDL_PATH} which I set
under MacOSX}

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. @file{.cshrc}), but from the file
@file{~/.MacOSX/environment.plist}.  Either include your path settings
there, or start Emacs and IDLWAVE from the shell.

@item @strong{I get errors like @samp{Symbol's function is void:
overlayp}}

You don't have the @samp{fsf-compat} package installed, which IDLWAVE
needs to run under XEmacs.  Install it, or find an XEmacs distribution
which includes it by default.

@item @strong{I'm getting errors like @samp{Symbol's value as variable is void:
cl-builtin-gethash} on completion or routine info.}

This error arises if you upgraded Emacs from 20.x to 21.x without
re-installing IDLWAVE.  Old Emacs and new Emacs are not byte-compatible
in compiled lisp files.  Presumably, you kept the original .elc files in
place, and this is the source of the error.  If you recompile (or just
"make; make install") from source, it should resolve this problem.
Another option is to recompile the @file{idlw*.el} files by hand using
@kbd{M-x byte-compile-file}.  Why not take the opportunity to grab the
latest IDLWAVE version at @uref{@value{IDLWAVEHOMEPAGE}, the maintainers
webpage}.

@item @strong{@kbd{M-@key{TAB}} doesn't complete words, it switches
windows on my desktop.}

Your system is trapping @kbd{M-@key{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 @kbd{@key{ESC}-@key{TAB}}.

@item @strong{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 @samp{!ERROR_STATE.MSG_PREFIX}, it is unable to parse these
message correctly.  Don't do that.

@item @strong{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 (@samp{IDL>
} by default).  You can do this with the variable
@code{idlwave-shell-prompt-pattern} (@pxref{Starting the Shell}), e.g.,
in your @file{.emacs}:

@lisp
(setq idlwave-shell-prompt-pattern "^\r? ?\\(ENVI\\|IDL\\)> ")
@end lisp

@item @strong{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 @kbd{C-h v idlwave-mode-version @key{RET}}.

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

The problem is that your Emacs is not finding the version of IDLWAVE you
installed.  Many Emacsen come with an older bundled copy of IDLWAVE
(e.g. v4.7 for Emacs 21.x), which is likely what's being used instead.
You need to make sure your Emacs @emph{load-path} contains the directory
where IDLWAVE is installed (@file{/usr/local/share/emacs/site-lisp}, by
default), @emph{before} Emacs' default search directories.  You can
accomplish this by putting the following in your @file{.emacs}:

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

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

@item @strong{IDLWAVE is screwing up the formatting of my @file{.idl} files.}

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

@lisp
(setcdr (rassoc 'idl-mode auto-mode-alist) 'idlwave-mode)
@end lisp

@item @strong{The routine info for my local routines is out of date!}

IDLWAVE collects routine info from various locations (@pxref{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, @samp{idlwave_catalog}.  Simply add a
line to your @samp{cron} file (@samp{crontab -e} will let you edit this
on some systems), like this

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

@noindent where @samp{MyLib} is the name of your library.  This will
rescan all @file{.pro} files at or below @file{/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.

@item @strong{All the Greek-font characters in the HTML help are
displayed as Latin characters!}

Unfortunately, the HTMLHelp files RSI provides attempt to switch to
@samp{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: @xref{HTML Help Browser Tips}.

@item @strong{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: @code{define_key,/control,'^d'} (e.g. in
your @file{$IDL_STARTUP} file) will disable the @samp{EOF} character
and give you a 512 character limit.  You won't be able to use
@key{C-d} to quit the shell, however.  Another possibility is
@code{!EDIT_INPUT=0}, which gives you an @emph{infinite} limit (OK, a
memory-bounded limit), but disables the processing of background
widget events (those with @code{/NO_BLOCK} passed to @code{XManager}).

@item @strong{When I invoke IDL HTML help on a routine, the page which
is loaded is one page off, e.g. for @code{CONVERT_COORD}, I get
@code{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 @uref{@value{IDLWAVEHOMEPAGE}, 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.

@item @strong{I get errors such as @samp{void-variable
browse-url-browser-function} or similar when attempting to load IDLWAVE
under XEmacs.}

You don't have the @samp{browse-url} (or other required) XEmacs package.
Unlike GNU Emacs, XEmacs distributes many packages separately from the
main program.  IDLWAVE is actually among these, but is not always the
most up to date.  When installing IDLWAVE as an XEmacs package, it
should prompt you for required additional packages.  When installing it
from source, it won't and you'll get this error.  The easiest solution
is to install all the packages when you install XEmacs (the so-called
@samp{sumo} bundle).  The minimum set of XEmacs packages required by
IDLWAVE is @samp{fsf-compat, xemacs-base, mail-lib}.

@end enumerate

@node GNU Free Documentation License, Index, Troubleshooting, Top
@appendix GNU Free Documentation License
@include doclicense.texi

@node Index,  , GNU Free Documentation License, Top
@unnumbered Index
@printindex cp

@bye