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 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
(~/.idlwave/, by default). It also re-scans the XML catalog if
it is newer than the current cached version. You can force rescan with
the menu entry
IDLWAVE->Routine Info->Rescan XML Help Catalog.
Before IDL 6.2, the HTML help was not distributed with IDL, and was not part of the standalone IDLWAVE distribution, but had to be downloaded separately. This is no longer necessary: all help and routine information is supplied with IDL versions 6.2 and later.
There are a variety of options for displaying the HTML help: see below. Help for routines without HTML documentation is also available, by using the routine documentation header and/or routine source.
In any IDL program (or, as with most IDLWAVE commands, in the IDL
Shell), press M-? (
idlwave-context-help), or click with
S-Mouse-3 to access context sensitive online help. The following
locations are recognized context for help:
|Routine names||The name of a routine (function, procedure, method).
|Keyword Parameters||A keyword parameter of a routine.
|System Variables||System variables like |
|System Variable Tags||System variables tags like |
|IDL Statements||Statements like |
|IDL Controls||Control structures like |
|Class names||A class name in an |
|Class Init Keywords||Beyond the class name in an |
|Executive Command||An executive command like |
|Structure Tags||Structure tags like |
|Class Tags||Class tags like |
|Default||The routine that would be selected for routine info display.
Note that the
OBJ_NEW function is special in that the help
displayed depends on the cursor position. If the cursor is on the
‘OBJ_NEW’, this function is described. If it is on the class
name inside the quotes, the documentation for the class is pulled up.
If the cursor is after the class name, anywhere in the argument
list, the documentation for the corresponding
Init method and
its keywords is targeted.
Apart from an IDLWAVE buffer or shell, there are two more places from which online help can be accessed.