[antlr-interest] Lexers hoist simple preds now

Ric Klaren klaren at cs.utwente.nl
Mon Sep 2 02:00:29 PDT 2002


Hi,

Good to see you at work on antlr again :) (now hope that I get some time in
the near future to do some of the last debugging sessions on the C++ part :( )

On Sat, Aug 31, 2002 at 04:27:54PM -0700, Terence Parr wrote:
> Haven't heard from anybody on my proposal, but I think it's a good idea
> so I've implemented it.  Works great for the "beginning of line issue."
>   Python-parsing lovers rejoice!
>
> You can gate rules in/out depending on semantic context now:
>
> A : {pred1}? 'a' ;
>
> Will only be tested upon pred1 by the lexer.  In prior versions, it
> would enter the rule and then fail (as a validating pred not
> disambiguating pred).

<cheers at Ter>

> NOTE the really cool thing is that the C++ and C# output generators
> will not have to be modified because the code generator is called after
> I build the internal representation of nextToken rule. :)  Woohoo!

<another cheer at Ter>

Some small questions:

Does this do anything for parsers as well ? (too lazy to read the code ;) )
I saw no patches in the documentation I trust these are still pending ;) ;) ;)

Cheers,

Ric
--
-----+++++*****************************************************+++++++++-------
    ---- Ric Klaren ----- klaren at cs.utwente.nl ----- +31 53 4893722  ----
-----+++++*****************************************************+++++++++-------
  Wo das Chaos auf die Ordnung trifft, gewinnt meist das Chaos, weil es
  besser organisiert ist. --- Friedrich Nietzsche


 

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