[antlr-interest] Need quick ANTLR/ST3 hack

[Sam Harwell]

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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