[antlr-interest] Re: A simple prepocessor with a lexer?

[maaxxxcal]

Wow thanks for your quick answer, it worked really well. I didn't 
know about the "filter" option.
One last thing though: I'd like to generate one token for each piece 
of text that is between my pragmas. How would you do that?
I tried to use filter=RULE to catch all the filtered text, but I 
don't know how to express "anything until the next pragma", since I 
cannot use ~PRAGMA (if PRAGMA is the rule defining the syntax of my 
pragma).

With the option filter=CODE, I tried

CODE: . ; (equivalent to filter=true)but that creates a token for 
every character
CODE: (.)*; but that consumes all the characters till EOF

What startegy would you use to effectively catch all the text between 
the pragmas?

Thanks again for your help!


--- In antlr-interest at yahoogroups.com, Terence Parr <parrt at c...> 
wrote:
> Hi.  Damn yahoogroups sucks.  Post from home didn't make it.  
Anyway, 
> try this:
> 
> class L extends Lexer;
> 
> options {
> 	filter=true;
> }
> 
> CMT : "--" ( PRAGMA | (options{greedy=false;}:.)* '\n' ) ;
> 
> protected
> PRAGMA : "<pragma"> ... ;
> 
> On Saturday, October 4, 2003, at 08:21 PM, maaxxxcal wrote:
> 
> > I am trying to write a very simple preprocessor but I'm not quite
> > sure how to go about it.
> > Here's the problem, I need to process pragmas that are really 
inside
> > single-line comments in a SQL script (not necessarily from the 
start
> > of line).
> > For instance, I can have input of the form:
> >
> > <sql>
> > ...
> > <sql> -- <pragma>
> > ...
> > <sql>
> >
> > What is the simplest way to achieve this with ANTLR? Is a lexer
> > enough as long as the syntax of the pragma is not too complex?
> > I tried writing such a lexer but I'm having trouble defining a 
rule
> > that would match "anything until --"
> >
> > Thanks for your help!
> >
> >
> >
> >
> > Your use of Yahoo! Groups is subject to 
> > http://docs.yahoo.com/info/terms/
> >
> >
> >
> --
> Professor Comp. Sci., University of San Francisco
> Creator, ANTLR Parser Generator, http://www.antlr.org
> Co-founder, http://www.jguru.com
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