[antlr-interest] how to allow keywords as variables
mzukowski at yci.com
mzukowski at yci.com
Fri Jun 6 09:38:42 PDT 2003
That won't work because you can't feed back to the parser from the lexer
reliably because the lexer has already lexed at least k tokens ahead.
However, something like that would work inside a TokenStream filter as
described in my page http://www.codetransform.com/filterexample.html,
because all the changing would be done before the parser knows about the
token.
Monty
-----Original Message-----
From: Ruslan Zasukhin [mailto:sunshine at public.kherson.ua]
Sent: Thursday, June 05, 2003 11:22 PM
To: antlr-interest at yahoogroups.com
Subject: Re: [antlr-interest] how to allow keywords as variables
on 6/6/03 1:57, mzukowski at yci.com at mzukowski at yci.com wrote:
> 2.7.2 still does not hoist, with the exception of hoisting from lexer
> rules into the nextToken() method.
>
> Ter's method would look like
>
> id_or_keyword:
> ID
> |"if"
> |"else"
> ;
>
> But this still can be cumbersome and generate lots of ambiguities
> which you might need to straighten out with syntactic predicates.
Okay, I see.
It seems I also have hear in mp3 word about ability resolve this using stack
of context state.
What about this?
For example
"drop" "table" { ExpectIdNow = true; } ID
And in lexer
ID:
if( ExpectIdNow )
then allow ID or keyword
else
keywords only.
Or something such?
--
Best regards,
Ruslan Zasukhin [ I feel the need...the need for speed ]
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