Re: context dependencies

[John P. Hartmann]

You will have to do that in the scanner using exclusive start states. 
When it meets blanks after a NUMBER or ID, it emits the SPACE token if 
the beginning of a number or identifier follows the blank(s):

<afternumid>{
[ \t]+/[a-z0-9]         BEGIN(INITIAL); return SPACE;
[ \t]+                  BEGIN(INITIAL);
}

On 12/02/2016 05:19 AM, Ricky Zhang wrote:
> I have read through 'handling context dependencies' section Bison manual.
> But I still haven't figured out the proper solution to my problem.
>
> We have production rule:
>
> expr : expr SINGLE_SPACE expr { /* some operation */ }
>         | expr + expr
>         ...
>         ;
>
> expr: NUMBER
>        | ID
>        ;
>
> and also for all white space [SINGLE_SPACE | \t]* in the language should be
> ignored. Are there any easy way to solve it?
>
> Thanks,
> Ricky
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