[Texmacs-dev] TeXmacs transformations

[Joris van der Hoeven]

Already a few comments on the draft; more will follow later.

* I rethought about the naming issue. I now prefer

        stree -> ttree; source tree -> tagged tree
        dtree -> rewriter

  In programs: ttree t, rewriter rew.
  Indeed, "source tree" is a bit confusing;
  tagged tree is better because each node is tagged by
  an inverse path to some location in the source.

* I like the idea about "observers"; I would use a phrasing
  close to this in order to characterize a rewriter:

  A rewriter observes changes in a source tagged tree and
  notifies the next rewriter about changes which have to
  be made in this tree after rewriting.
  At the end of the chain, there is no next rewriter and
  the result of the rewriting is rendered.

* I do not understand quite well the use of ptree.
  You mean that this can be used in order to give an additional
  kind of styling information on how to render the document?

  In that case, there is a better approach: consider source ttrees
  which are pairs (t, st), where t is the real ttree and
  st the additional styling information. You might place
  an *additional* rewriter in front of the chain of rewriters
  which makes changes in t so that it will be rendered as you wish.

  As a general rule, don't forget that rewriters can be combined;
  this is a *very powerful* mechanism.

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Joris van der Hoeven <address@hidden>
http://www.texmacs.org: GNU TeXmacs scientific text editor
http://www.math.u-psud.fr/~vdhoeven: personal homepage
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