On Tuesday 06 October 2009 03:15:05 am Graham Wideman wrote: > Hi folks: > > I see in the ANTLR grammar that you can place a BANG (exclamation point) > after the initial rule id in a rule. Indeed it's used in the ANTLR v3 grammar > itself: > > ---------------------------- > range! > : c1=CHAR_LITERAL RANGE c2=CHAR_LITERAL elementOptions? > -> ^(CHAR_RANGE[$c1,".."] $c1 $c2 elementOptions?) > ; > ---------------------------- > > Could someone illuminate what this ! does?
The exclamation mark is placed on a node when that node should not be present in the AST when output=AST for a grammar. See: http://jnb.ociweb.com/jnb/jnbJun2008.html#CreatingASTs http://www.antlr.org/wiki/display/ANTLR3/Tree+construction --Kaleb http://twitter.com/kalebpederson http://kalebpederson.com List: http://www.antlr.org/mailman/listinfo/antlr-interest Unsubscribe: http://www.antlr.org/mailman/options/antlr-interest/your-email-address --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "il-antlr-interest" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/il-antlr-interest?hl=en -~----------~----~----~----~------~----~------~--~---
