[antlr-interest] ambiguous grammar

[jagad]

Hi Jbb,

> 
> I haven't actually tried running this through the antlr.Tool, but I
> think it is unambigous:
> 
> rule1  : '(' expr (COMMA expr)* ')'
> expr   : factor (op factor)*
> factor : INTEGER | rule1
> op     : '+' | '-'
> 

Yes, it's works, Thanks!

> But the above accepts "(1,2)+3" or "3+(2,1)" while your original
> grammar does not. I think a simple semantic error check for the
> presence of a COMMA when an op is encountered would be easy to add if
> that restriction is important...

Correct, the semantic error checking is easy to do with ANTLR, now my
Delphi/Kylix grammar is works :)

> 
> Hope this helps.
> 	-jbb
> 

It's very helpfull to me :)

Thanks and Kindest Regards

jagad


 

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