Re: context dependencies

[Ron Burk]

Hi Ricky,

Just curious: What actually terminates an 'expr' production? For example,
if they were terminated by newlines and the parser encountered this token
stream:
  ID SINGLE_SPACE '\n'
do you intend to treat that as a "missing right-hand-side of SINGLE_SPACE
operator" error?

Likewise, I guess you're saying that this token stream:
    ID SINGLE_SPACE SINGLE_SPACE ID
would generate a syntax error, penalizing the user who accidentally (or to
make things line up) uses two spaces instead of one?

Trying to figure out exactly where the context boundaries are within which
you want white space to become significant.

Ron



On Thu, Dec 1, 2016 at 8:19 PM, Ricky Zhang <address@hidden> 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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>