Small correction:
The 2 rules are:
sentence: /* empty */
| sentence line optional_comma '$' { printf("\nInput line:
>>>%s ::: %s <<<\n", $2, $3); }
;
sentence: line optional_comma '$' { printf("\nInput line: >>>%s :::
%s <<<\n", $2, $3); }
;
On Sat, May 2, 2009 at 2:51 PM, Samkit Jain <samkit.fe...@gmail.com> wrote:
> Hi,
>
> And I created a small program to test some small fundamentals and found
> that there is a lot of difference between the below 2 rules.
>
> sentence: /* empty */
> | sentence line optional_comma '$' { printf("\nInput line:
> >>>%s ::: %s <<<\n", $2, $3); }
> ;
>
>
> sentence: sentence line optional_comma '$' { printf("\nInput line:
> >>>%s ::: %s <<<\n", $2, $3); }
> ;
>
> I am using scanf in yylex (my own yylex), which always accepts some string.
>
> And now I am confused as to why is "/* empty */" necessary even when empty
> cannot be returned by yylex.
>
> When I checked the states generated by the parser, I found that there is a
> difference in the way $default and $end are created for some states.
>
> Can someone please tell me basic principle behind $end and $default
> terminal symbols.
>
>
> : Samkit Jain
>
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