[antlr-interest] Please advice about float

[Bryan Ewbank]

The original looks okay to me as a way to parse integers or simple
floats.  The problem with proposed change:
   NUMBER : (INT '.' INT) | INT ;
is that it is ambiguous under LL, whereas the original:
   NUMBER : INT ('.' INT)? ;
is not - it has been left-factored.

Note that it does not allow .019, but requires the leading zero before
the dot: 0.019.

- Bryan


On 9/19/05, denis, alexis <adenis at bristol.ca> wrote:
> I'm no  expert in grammars but I'd say a float is an (INT'.'INT) and a NUMBER is
> a  FLOAT or an INT. 
>
> -----Original Message-----
> From: Gevik babakhani    [mailto:gevik at xs4all.nl]
>
> NUMBER             :           INT    ((FLOAT)?)   ;
> FLOAT                 : ('.' INT)   ;   
> INT                      : (DIGIT)+ ;   
> DIGIT                   : '0'..'9'  ;