Thank you for your answer, Bart.
But if I do what you are suggesting, my parser rules will look like this:
intexpr: INTTOKEN arithexpr CB { ... };
Instead of this (which is more readable):
intexpr: INTTOKEN OB arithexpr CB { ... };
But, ok, I have a solution to make it work.
But my questions were more about understanding how it is working internally.
Why having 2 lines in the lexer makes it different as having a single line ?
AT : '@';
NAME : ALPHA (ALPHA | DIGIT)*; ...
Instead of
ATNAME: : '@' NAME;
Regards,
Philippe
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Bart Kiers
Sent: 02 March 2010 19:01
To: [email protected]
Subject: Re: [antlr-interest] behaviour of lexer
On Tue, Mar 2, 2010 at 5:25 PM, Philippe Frankson <
[email protected]> wrote:
> ...
> @int('444') is a function converting a string into integer.
> If I don't have parentheses, then it is not a function, it is only a column
> name. Ex.: @test, @integer, @in, ....
>
> Here is a part of lexer rules:
>
> fragment DIGIT : ('0'..'9');
> fragment ALPHA : ('a'..'z'|'A'..'Z'|'_');
>
> OB : '(';
> INTTOKEN : ('@int' OB)=> '@int'; // so I check if there is an open
> parenthesis to return INTTOKEN.
> AT : '@';
> NAME : ALPHA (ALPHA | DIGIT)*; ...
>
Why not just include the OB in your lexer rule?
Something like this:
INT_METHOD : AT 'int' OB; // or: AT 'int' OB STRING CB;
COLUMN : AT NAME;
OB : '(';
AT : '@';
NAME : ALPHA (ALPHA | DIGIT)*;
fragment DIGIT : ('0'..'9');
fragment ALPHA : ('a'..'z'|'A'..'Z'|'_');
and because lexer rules are matched from top to bottom, '@int' will be
matched as 'AT NAME'.
Regards,
Bart.
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