[antlr-interest] Antlr 3 Lexer problem

[Jim Idle]

Don't try to construct syntactical context in the lexer basically:

grammar T;
 
options {
 	language=CSharp;
 	backtracking=true;
}
 
ID : ('a'..'z')+;
 
LPAREN : '(';
 
SELECT : 'select';
 
prog: (ID | LPAREN SELECT?)+ ;


> -----Original Message-----
> From: antlr-interest-bounces at antlr.org [mailto:antlr-interest-
> bounces at antlr.org] On Behalf Of Geoffrey Zhu
> Sent: Tuesday, June 26, 2007 11:28 AM
> To: antlr-interest at antlr.org
> Subject: [antlr-interest] Antlr 3 Lexer problem
> 
> Hi,
> 
> I have a simple lexer problem. The below grammar will fail on "(
> security" in the lexer, because when the lexer sees '(' and then sees
> 's' , it will try to match the LP_SELECT rule, which cannot be
matched.
> In this case, I want the lexer to return LPAREN and then ID. How can I
> do that?
> 
> Thanks a lot,
> Geoffrey
> 
> 
> grammar T;
> 
> options {
> 	language=CSharp;
> 	backtracking=true;
> }
> 
> ID : ('a'..'z')+;
> 
> LPAREN : '(';
> 
> LP_SELECT : LPAREN 'select';
> 
> prog: (ID | LPAREN | LP_SELECT)+ ;
> 
> _______________________________________________________
> 
> The  information in this email or in any file attached
> hereto is intended only for the personal and confiden-
> tial  use  of  the individual or entity to which it is
> addressed and may contain information that is  propri-
> etary  and  confidential.  If you are not the intended
> recipient of this message you are hereby notified that
> any  review, dissemination, distribution or copying of
> this message is strictly prohibited.  This  communica-
> tion  is  for information purposes only and should not
> be regarded as an offer to sell or as  a  solicitation
> of an offer to buy any financial product. Email trans-
> mission cannot be guaranteed to be  secure  or  error-
> free. P6070214