Greetings!
On Tue, 2011-06-07 at 07:41 -0400, David Smith wrote:
> I'm parsing a grammar in which the semicolon on the end of a line is
> optional. So two of the statement rules might be:
> | (ID GETS expr SEMI) => ID GETS expr SEMI -> ^(GETS ID expr SEMI)
> | (ID GETS) => ID GETS expr -> ^(GETS ID expr)
> Since this occurs with a number of different assignment statements, I
> would really like to collapse this into one rule that looks something
> like this:
> | (ID GETS) => ID GETS e=expr (s=SEMI)? -> ^(GETS ID $e $s)
> but every implementation I can think of either refuses to generate
> the grammar or, as in the case above, generates the grammar but
> decides that the variable 's' is unknown.
> Is there a any way to achieve this?
Have you tried:
| (ID GETS) => ID GETS e=expr (s=SEMI)? -> ^(GETS ID $e $s?)
is the semicolon really necessary in the tree? (e.g. does the presence
of the semicolon actually change the meaning of of the statement?)
perhaps:
| (ID GETS) => ID GETS^ expr SEMI!?
Hope this helps...
-jbb
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