[antlr-interest] please help on lexer rules antlr v3

[Michiel Vermandel]

Hi Ter,

I tried your solution but unfortunatly still the wrong rule is used...

I stripped down the grammar to it's smallest in order to test (see blow).

I'm using AntlrWorks 1b3 together with the Antlr version delivered with 
AntlWorks.

My test string is:

-- axi.reject

followed by a single CRLF

Any idea why the   -- axi.reject  is still consumed as  a comment (on 
channel 99) ?

Thanks!

Michiel

---------------------------- grammar --------------------------

grammar TestParser;
options {k=2; backtrack=true; memoize=true;}

statement: (directive )+ EOF;

directive: DIRECTIVE;


LF      :       '\n' { channel=99; };

CRLF    :       '\r' ('\n')? { channel=99; };

TAB     :       '\t' { channel=99; };

SPACE   :       ' ' { channel=99; };

fragment
ANYTHING_2_EOL: (~('\n'|'\r' ))* ('\n'|'\r'('\n')?);

fragment
DIRECTIVE: (SPACE | TAB )* ('axi.locate' | 'axi.reject');

// Single-line comment
SL_COMMENT:  '--' ( DIRECTIVE | ( ANYTHING_2_EOL { channel=99;} ) );

WS      :       ( TAB | SPACE | CRLF | LF )+ { channel=99; };


--------------------------------------------------------------------------------------------------------------------








On Sep 27, 2006, at 6:50 AM, Michiel Vermandel wrote:

>
> Hi,
>
> I have the following two rules in my lexer.
>
> DIRECTIVE: '--' (TAB | SPACE)* ('axi.locate' | 'axi.reject');
>
> // Single-line comments
> SL_COMMENT:  '--' (~('\n'|'\r'))* ('\n'|'\r'('\n')?)  { channel=99; };
>
> the general idea is that
>
> -- axi.locate 
> -- axi.reject 
>
> are compiler directives,
>
> -- followed by anything else 
>
> is a comment.
>
> now (obviously :-/ ) everything starting with -- is consumed by the 
> SL_COMMENT rule.

LL(*) should handle this, but if not, then just do

SL_COMMENT : '--' DIRECTIVE | ... ;

fragment DIRECTIVE : ... (TAB | SPACE)* ('axi.locate' | 'axi.reject') ;

Ter


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