Re: [Texmacs-dev] Literate Programming in TeXmacs?

[Felix Breuer]

Hello again!


One of the unique features of TeXmacs are its session plugins. I have
frequently have found myself wanting to "rerun" a sequence of
computations in a session with some slight modifications. In this
fashion an interactive session can even turn step by step into a
program. Thus, it is a natural idea to integrate a potential LP feature
of TeXmacs with its session features.


A simple implementation that serves both purposes might look as
follows. Suppose snippets of code in the document are wrapped in an
environment like

  <lp-code|label|body>

where label is an arbitrary string that marks which snippets belong
together and body is an arbitrary TeXmacs tree that is "the code". Now
the LP implementation might have a function

   (label-to-code label filter)

at its core that does:

  * collect all nodes in the document that are of type "lp-code" and
    have label _label_ as their first argument
  * apply the export filter _filter_ to the second arguments of each of
    the nodes in turn
  * concatenate the resulting list of strings and return it.

The resulting string could then either be written to a file or fed to a
session line by line.


Some comments:

* This bare-bones solution should be really simple to implement.
* One can add custom source code formatting and generation methods
  simply by writing a style file and accompanying export filter. This
  would
  - make use of standard TeXmacs mechanisms
  - tie in with the use of filters to store entire TeXmacs documents as
    ASCII source code files as David and I had envisioned
  - allow one to copy-and-paste fancy formatted code from TeXmacs into
    a text editor.
* Instead of using a fixed environment name like "lp-code" and
  plain-text labels, one should probably use DRD properties and loci (I
  just have no idea how these work).
* One could add facilities to reorder code chunks during code
  generation later on.


So much for now. Comments are welcome!

Felix