Re: {Spam?} Re: state in parsers

Kristof Bastiaensen writes:
> Can the lexer be controlled from the parser, or are they
> totally separated?  Can I modify lexer state from the parser?
> Is that such a hard question?

It is.

The lexer and the parser are separated. But since this is Emacs Lisp,
nothing really is 'totally' separate. Since you can call pretty much any
Emacs Lisp code in your actions, you are free to set some variable there
which affects how your lexers work.

The LL parser (Bovine) does something similar with the EXPAND/EXPANDFULL
actions, which incrementing a 'depth' variable and call the parser
recursively. This variable defines the depth with which the lexers
should look into '{}' and '()' blocks (otherwise they simply return a
'semantic-list' token).

AFAIK, the Wisent parser does not support this out of the box, but you
should be able to cook up something similar, but maybe you have to dig
into the Wisent code a bit to get this right. Sorry I cannot give you a
better answer.

-David

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