[antlr-interest] Lines that don't match a rule ...

[James Ladd]

Hi Jim and Others ...

The suggested grammar (which I have modified slightly) below works in most
cases except when I parse the following:

\n
+ add: value\n
   ^ self + value\n
\n

What I was hoping for is that line three (3) '^ self + value\n' is a seen as a line not starting with '+' | '-'
and consumed entirely - But I get a No Viable Alternative Exception.

Please can some one help ?

Rgs, James.

lines
  : (line LINE_BREAK)* EOF
  ;
 
line
  : ('+' | '-') (unarySelector | keywordSelector | binarySelector)
  | { while (input.LA(1) != LINE_BREAK && input.LA(1) != EOF) input.consume(); }
  ;

unarySelector
  : NAME
  ;

keywordSelector
  : (KEYWORD NAME)+
  ;

binarySelector
  : (BINARY_SYMBOL| '-' | '+')  NAME
  ;

LINE_BREAK: ('\r'? '\n' | '\r');
NAME: ('a'..'z' | 'A'..'Z')('a'..'z' | 'A'..'Z' | '0'..'9')*;
KEYWORD: NAME ':';
BINARY_SYMBOL: ('~'|'!'|'@'|'%'|'&'|'*'|'-'|'+'|'='|'\\'|'|'|'?'|'/'|'>'|'<'|',') ('~'|'!'|'@'|'%'|'&'|'*'|'-'|'+'|'='|'\\'|'|'|'?'|'/'|'>'|'<'|',')*;

> 
> Message: 7
> Date: Wed, 6 Jul 2011 16:30:52 -0700
> From: Jim Idle <jimi at temporal-wave.com>
> Subject: Re: [antlr-interest] Lines that don't match a rule ...
> To: antlr-interest at antlr.org
> Message-ID: <6556c9d271c906dfb308bb73f0e8e262 at mail.gmail.com>
> Content-Type: text/plain; charset=UTF-8
> 
> Try:
> 
> lines
>   : (messagePattern LINE_BREAK)* EOF
>   ;
> 
> messagePattern
>   : ('+' | '-') (unarySelector | keywordSelector | binarySelector)
>   | { while (input.LA(1) != LINE_BREAK && input.LA(1) != EOF)
> input.consume(); }
>   ;
> 
> This will just eat the lines that don't
> 
>