Hello Christian, The => operator indicates a 'syntatic predictate'. It's a device for selecting between two, otherwise ambiguous alternatives.
There is a terse definition here: https://wincent.com/wiki/ANTLR_predicates and a slightly friendlier one here: http://www.antlr.org/wiki/display/ANTLR3/How+to+remove+global+backtracking+from+your+grammar I'd also recommend you get the ANTLR books. Michael On 25 November 2011 13:44, Christian <chw...@gmx.de> wrote: > Hi community, > > I stumble across the => operator and the following rule: > > arule > : (identifier generic_argument_list) => identifier generic_argument_list > | identifier > ; > > Why is this rule not equivalent to the following one? > > brule > : identifier generic_argument_list? > ; > > I admit that I do not find the operator on the antlr site, thus I do not > read any documentation about the semantics of =>. > > Please, can someone tell me? > > Thanks, > Christian > > 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-inter...@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.
