[antlr-interest] Lexer question

[Micheal J]

Hi,

> Thank you for your solution, it works very well.
> I have another one, it looks like the same ;)
> 
> In the lexer -------------------
> INTORDOUBLE
> 	: (INTEGER '.') => DOUBLE	{ $setType(DOUBLE); }
> 	| INTEGER			{ $setType(INTEGER); }
> 	;

Syntactic predicates (e.g. "(INTEGER '.') => DOUBLE" ) are expensive as they
can involve guessing/backtracking. Particularly bad in a lexer.

See how the KCSParse/csharp_v1 sample lexes numeric tokens. No synpreds
iirc.


Micheal

-----------------------
The best way to contact me is via the list/forum. My time is very limited.