[TxMt] Performance issues

[Jonathan Ragan-Kelley]

> Regular Expressions can do an awful lot in the arena of
> text processing; but a lot of what an editor used by programmers
> needs to do can not be done at all, or at least very well, by over
> reliance on Regular Expressions.

While I agree with the desire for ever more powerful mechanisms, I'd
like to speak up quickly just to say that what Allan has effectively
created with the scope system, used both for styling and for
commands/etc. is a real parser -- a CFG or set of CFGs -- not a mere
regular expression, because of the ability to nest elements in a
language grammar.  Just like in a conventional machine language
parser, regular expressions are used to recognize individual parse
elements, but the structure it generates and uses to analyze and
represent the code or other file contents is context-free, and hence
just about as powerful as anything used in other editors, even up to
the level of Eclipse's fancy-dan refactoring tools and so forth.  What
could make this more accessible for more advanced tools might be a
more direct API to run over (and potentially transform) the parse
tree, not just the current context, but what it does now is still much
more powerful than mere regular expressions.
-jrk