[antlr-interest] Re: second lexical pass - yeah

[idontwantanidwith2000init]

It recognized DATE in the parser :)
Now, could you review it:
protected
DATE
	: YEAR
	  '-' MONTH
	  '-' DAY
	  ' ' HOUR
	  ':' MINUTES
	  ':' SECONDS
	;
// string literals
STRING_LITERAL
	: 	'"'! (~('"'|'\n'|'\r'|'\\')|'\\' .)*'"'!
		{
			try
			{
				ScriptLexer scriptLexer = new 
ScriptLexer(new StringReader($getText));
				scriptLexer.mDATE(false);
				$setType(DATE);
			}catch(ANTLRException exp){
				$setType(STRING);
			}
		}
	;

I've done all the neccesary imports.
If you like it, Terr, maybe it deserve a place in the FAQ...

This is just great.

Tal.
--- In antlr-interest at yahoogroups.com, "idontwantanidwith2000init" 
<idontwantanidwith2000init at y...> wrote:
> I've ment multiple values of course :)
> That's what I wanted to do, Terr, more or less. :)
> I'm sad though. With lex I could handle it without a second parser.
> But it seems a better aproch then putting it all together in one 
> parser.
> Let me explain why:
> '"'YYYY-MM-DD hh:mm:ss'"' is a STRING.
> and there isn't a simple way to express this relationship.
> Maybe it's an idea for improving the lexer.
> 
> What do you think?
> 
> --- In antlr-interest at yahoogroups.com, Terence Parr <parrt at c...> 
> wrote:
> > 
> > On Apr 11, 2004, at 6:25 AM, idontwantanidwith2000init wrote:
> > 
> > > Is there an elegant way to do a second lexical path instead of
> > > writing two lexers?
> > >
> > > For instance:
> > > STRING_LITERAL:
> > > '"' (~('\r'|'n'|'\\') | '\\' .) '"' ;
> > >
> > > now STRING_LITERAL will colide with any special string you'd 
> like to
> > > match, for instance:
> > > DATE_TIME : '"'YYYY-MM-DD hh:mm:ss'"'
> > >
> > > I've managed to merge it with:
> > > '"'(LETTER)*'"'
> > > '"'(LETTER)*'.'(LETTER)*'"'
> > > '"'(LETTER)*'-'(LETTER)*'"'
> > > Which was a diffucult task but doable.
> > >
> > >
> > > I thought about it and merging these rules is possible, but it 
> will
> > > take me days to write it and we haven't talked about 
validation.
> > > (It is a good to write down my thoughts I'm starting to 
convince
> > > myself that it is a good idea)
> > >
> > > What do you think is a proper solution?
> > 
> > My first thought is that you have a two-level grammatical issue 
> here.  
> > First you have to match a string and then determine if it 
> satisfies a 
> > "nested structure" which is the date/time stuff.  You can't 
really 
> use 
> > another rule in the same lexer object as it will consume the 
> input.  
> > Perhaps a compromise.  Make a new lexer rule that will match 
> DATE_TIME 
> > as you've done and make it protected.  Then, make a *new* 
instance 
> of 
> > your lexer.  Set it up with a copy of the text matched inside 
the 
> > string and then directly call DATE_TIME with a try/catch around 
it 
> to 
> > catch failure.  Gotta love LL based lexers :)
> > 
> > Ter
> > --
> > Professor Comp. Sci., University of San Francisco
> > Creator, ANTLR Parser Generator, http://www.antlr.org
> > Cofounder, http://www.jguru.com
> > Cofounder, http://www.knowspam.net enjoy email again!
> > Cofounder, http://www.peerscope.com pure link sharing



 
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