[antlr-interest] Nasty LHS expression

[Bart Kiers]

Hi David,

Can an `expr` match something that starts with `ID OPENP` and/or `ID GETS`?
Perhaps you can post your entire grammar? Or at least the `expr` rule?

Regards,

Bart.


On Thu, May 26, 2011 at 7:02 PM, David Smith <david.smith at cc.gatech.edu>wrote:

> I am having a difficult time distinguishing two legal lines of code:
>   ID = expression
> and
>   ID(exp1, exp2, ...) = expression
> I tried this rule:
> stat:   expr NEWLINE        -> expr
>     |   (ID OPENP .* CLOSEP GETS)
>          => ID OPENP actualParameters CLOSEP GETS expr NEWLINE
>          -> ^(INDEX ID OPENP actualParameters CLOSEP expr)
>     |   ID GETS expr NEWLINE -> ^(GETS ID expr)
>     |   NEWLINE             ->
>     ;
> But it says that alternatives 2 and 3 can never be matched.  How do I
> "reactivate" 2 and 3?
>
>                                 DMS
>
>
> David M. Smith http://www.cc.gatech.edu/fac/David.Smith
> Georgia Institute of Technology, College of Computing
> Sent from my ASR-33 Teletype
>
>
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