Tilman, thanks for the suggestion. Sadly, that approach will only work if a and b are literals. It will not work if the non-terminals a and/ or b represent identifiers whose type can only be determined by checking the symbol table.
Cheers, D On May 15, 2009, at 4:43 AM, Tilman Bender wrote: > Hi David, > > I think this is possible with rewrite rules, but it depends on how > you structure you grammar: > > e.g. Have lexer rules for STRING, INT, FLOAT so you could do things > like > > expr: > a=STRING '+' b=STRING -> ^(CONCATENATE a b) > | a=number '+' b=number -> ^(PLUS a b) > ; > > number: > INT > | FLOAT > ; > > This is just a quick brain-dump but might give you hints in the > right direction. > > Tilman Bender > Student des Software Engineering > Hochschule Heilbronn > tben...@stud.hs-heilbronn.de > > > > Am 15.05.2009 um 05:38 schrieb David Jameson: > >> Is there any way to control the built-in tree generation (from an >> initial parse phase) based on semantics of what is being parsed? >> >> As a simple example, if I see the expression >> a + b >> >> then I want to produce >> (PLUS a b) >> or >> (CONCATENATE a b) >> >> depending on whether a and b are numeric or string. >> >> >> How can I do this with rewrite rules (for example)? Or do I have to >> construct my own trees? >> >> >> Thanks, >> D >> >> List: http://www.antlr.org/mailman/listinfo/antlr-interest >> Unsubscribe: >> http://www.antlr.org/mailman/options/antlr-interest/your-email-address > > > 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 il-antlr-interest@googlegroups.com To unsubscribe from this group, send email to il-antlr-interest+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/il-antlr-interest?hl=en -~----------~----~----~----~------~----~------~--~---
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