[antlr-interest] newbie question, escaped characters

Rob Shields rob at cmsnet.org.uk
Tue Mar 11 13:15:33 PDT 2008


Gavin Lambert wrote:
> At 07:57 12/03/2008, Rob Shields wrote:
>  >protected TERM_CHAR: SIMPLE_TERM_CHAR | ESCAPED_TERM_CHAR |
>  >WILDCARD_TERM_CHAR;
>  >
>  >protected SIMPLE_TERM_CHAR:  ~( ' ' | '\t' | '!' | '(' | ')' | ':'
>  >| '^' |
>  >                          '[' | ']' | '\\' | '\"' | '{' | '}' | '~'
>  >| '/' |
>  >                          '\r' | '\n' );
>  >
>  >protected ESCAPED_TERM_CHAR:  '\\'! ( '\\' | '+'  | '-' | '!' | '('
>  >|
>  >')' | ':' | '^' |
>  >                               '[' | ']' | '\"' | '{' | '}' | '~' |
>  >'/');
>  >
>  >protected WILDCARD_TERM_CHAR: '\\' ( '*' | '?' );
>  >
>  >This gives a warning about lexical nondeterminism
>  >(ESCAPED_TERM_CHAR and WILDCARD_TERM_CHAR both start with \)
>  >and WILDCARD_TERM_CHAR doesn't work. If I swap around
>  >ESCAPED_TERM_CHAR and WILDCARD_TERM_CHAR, then
>  >ESCAPED_TERM_CHAR doesn't work.
> 
> What's the value of k?  Is it at least 2?

Sorry, I'm not sure what k is.



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