[antlr-interest] Need quick ANTLR/ST3 hack

[Bill Andersen]

Thanks, Sam...

That works - never used those ST operators before.


On Sep 14, 2011, at 15:09 , Sam Harwell wrote:

> I believe <if(rest(args))> will evaluate to true if args has more than one
> item.
> 
> Sam
> 
> -----Original Message-----
> From: antlr-interest-bounces at antlr.org
> [mailto:antlr-interest-bounces at antlr.org] On Behalf Of Bill Andersen
> Sent: Wednesday, September 14, 2011 1:26 PM
> To: antlr-interest
> Subject: [antlr-interest] Need quick ANTLR/ST3 hack
> 
> Folks
> 
> I want to write a template containing a conditional expansion for a
> multi-valued attribute that does one thing if the attribute is singleton and
> another if there are more than 1 element
> 
> For example, in an ANTLR grammar with ST output
> 
> rule
>  : FOO (bars+=bar)+ -> foo(args={$bars})
>  ;
> 
> where the template looks like
> 
> foo(args) ::= <<
> <if(???)>
>  something
> <else>
>  something else
> <endif>
>>> 
> 
> I want some expression for ??? to test for args being singleton.
> 
> Is this possible in ST3?  Else I imagine I could write:
> 
> rule
>  : FOO (bars+=bar)+ -> foo(args={$bars},singleton={$bars.size() == 1})
>  ;
> 
> and
> 
> foo(args,singleton) ::= <<
> <if(singleton)>
>  something with args
> <else>
>  something else with args
> <endif>
>>> 
> 
> ... but I would really rather not.
> 
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