[antlr-interest] about space between operator

[Bart Kiers]

Try this:

NOTEQUALS
  :  '<>'
  ;

LT
  :  '<' (' '+ '>' {$type=NOTEQUALS;})?
  ;

Regards,

Bart.


On Mon, Dec 5, 2011 at 8:14 AM, 李志鹏 <lizhipeng at gmail.com> wrote:

> hello all
>
> I have a very simple grammar like this:
> grammar AA;
>
> expression
> : TYPE_DOUBLE (NOTEQUALS | LT)  TYPE_DOUBLE EOF
> ;
>
> NOTEQUALS
> : '<>' | '<' (' '+) '>'
> ;
>
> LT : '<';
>
> TYPE_DOUBLE
> :   Digit+ '.' Digit*
> |   '.' Digit+
> ;
>
> fragment
> Digit
> : '0'..'9'
> ;
> WS
> :  (' '|'\r'|'\t'|'\u000C'|'\n')+ {$channel=HIDDEN;}
> ;
>
> if input "1.6<>1.7" or "1.6<1.7" or "1.6 <>  1.7", it is ok
> but input "1.6 < 1.7"(has white space on both sides '<' ), the grammar
> can't resolve it
>
> if I change as this
> NOTEQUALS
> : '<>'
> ;
> above all are ok, but "1.6 <   > 1.7" is not work, I wan't use "<>" to mean
> not equal,  and white space is allow between "< >", How Can i do?
>
> thank you all
>
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