[antlr-interest] Re: ANTLR meta-syntax question

[jsrs701]

--- In antlr-interest at y..., mzukowski at y... wrote:
> ANTLR requires the parenthesis.  It makes it easier to associate 
actions
> with the proper construct, e.g. inside or outside of the ()+ 
closure.
> 

Hi Brian,

Since you're new to ANTLR, that might not make much sense without an 
example, though it's a very good answer.

A: ( B )+ ;

That seems redundant, sure.  But what about when you add the actions 
that Monty mentioned?

A: ( B { /* do something with this particular B */ } )+
   { /* do something with the group of matched B's */ }
 ;

How would you do that without the parentheses?

ANTLR just requires them, whether or not the actions are there.  Such 
is life.  But I've found that I end up using the parentheses a lot 
more than I first expect once I start assigning actions.

JSRS


 

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