[antlr-interest] Please help with arbitrary arrangements and old BNF syntax

Matt Benson gudnabrsam at yahoo.com
Fri Dec 16 12:33:55 PST 2005


Also, when you have a set as small as three, you could
use this non-scaling approach:

test
  :  (  foo (bar (baz)? | baz)?
     |  bar (foo (baz)? | baz)?
     |  baz (foo (bar)? | bar)?
     )?
  ;

FWIW,
Matt

--- Brannon King <BBKing at starbridgesystems.com> wrote:

> Suppose I have the following parser rule snipped
> from edif.org:
> 
> written :
> 	LP! "written"
> 	     timeStamp
> 	     ( < author > | < program > | < dataOrigin > |
> 	     property | comment | userData )*
> 	RP!;
> 
> Where the angle brackets mean that those can only
> appear once (in an
> arbitrary order). How do I enforce this in an ANTLR
> grammar?
> 
> In a similar vein, is this the right way to limit an
> identifier length?
> 
> IDENTIFIER
> 	options {testLiterals=true;} //make sure it's not a
> built in
> function
> 	:	(ALPHA|'&')	a:('_'|ALPHA|DIGIT)*
> {a.getText().length() < 256}? ; //less than 256
> chars total
> 
> Thanks for your time
> 


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