A macro and/or template processor written in Tcl for Tcl, by [William Duquette].
See http://www.wjduquette.com/expand/index.html for its homepage.

This is a useful tool for conversion of tcl-based documents into other formats. The range of applications include

   * Generation of website with uniform look & feel. See the homepage [http://www.wjduquette.com/] of the expand author, or [AK]'s [memchan] website at SourceForge [http://memchan.sourceforge.net] for examples of this.
   * Conversion of manpages in a tcl-based markup to HTML, nroff, TMML, etc.

   * Generation and setup of Makefiles for an extension based upon a template.

   * Provide a generic support to update a set of files depending on single definition file (tcl script)

All of this falls under the broad category of [Template and Macro processing].



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BUT, with 8.5, expand also becomes the closest thing Tcl has to a conventional keyword.  See TIP 157 [http://www.tcl.tk/cgi-bin/tct/tip/157.html] for the
details.
[[expand [syntax] ...]]

[[Would someone please take on the painful task of explaining the Tcl 8.5
meaning of expand in a way that a Tcl novice will understand?]]

[NEM] OK - here's an attempt at explaining {expand} in Tcl 8.5. The easiest way to explain is perhaps with an example. Consider the following code, which may be used for launching a browser on Windows:

 eval exec [auto_execok start] [list $url]

The reason that the [[eval]] is there is that [[auto_execok]] may return a list which represents the command to be run. This list needs to be flattened for exec. For instance, let's say [[auto_execok start]] returned:

 % auto_execok start
 c:/windows/command.com /c start

If you just did:

 exec [auto_execok start] $url

You would get an error about "can't find 'c:/windows/command.com /c start' - no such file or directory" or something similar. In order to flatten this list, you currently have to use [[eval]] which does this for you (as it [concat]s its arguments together before evaluation). But because the $url may contain spaces, we need to protect it, so that it doesn't get flattened. Hence the use of [[list]], and the full line given at the start. There are lots of gotchas with quoting arguments correctly for [[eval]]. So, to solve this problem, 8.5 introduced the {expand} syntax, which inline expands arguments in a command invocation. What this means is that {expand}''list'' becomes ''word word word...'' at invocation time. So, we can now rewrite our example (in 8.5) as:

 exec {expand}[auto_execok start] $url

Which is clearer, safer and better all round.

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[Category Application] | [Category Package], a part of [Tcllib] (/[textutil])
| [Category Command]