I think I agree with that for all the situations which come to mind easily. Using lexer modes to infer semantic context would be sugar frosting at best and an invitation to poor design at worst. Point taken.
Kyle On 5/27/10, Terence Parr <[email protected]> wrote: > The lexer/parser really shouldn't interact since they can operate totally > independently. In most cases what you really want is a scannerless parser, > which I think I can easily implement as well. > > Ter > > On May 26, 2010, at 7:07 PM, [email protected] wrote: > >> Way cool! Just curious...is the modal state variable automatically >> accessible to the parser? Perhaps on a subchannel synced with the token >> stream? Sorry to be tuning in late...always interested in new paths to >> semiosis. :) Anyway...I need to take a look at girhub and think up a >> fun use. >> >> Kyle >> >> Sent from my Verizon Wireless BlackBerry >> >> -----Original Message----- >> From: Terence Parr <[email protected]> >> Date: Wed, 26 May 2010 16:18:28 >> To: [email protected] interest<[email protected]> >> Subject: [antlr-interest] ANTLR v4 progress >> >> Just passing along an example HTML subset lexer/parser using ANTLR v4; >> thanks to debugging and moral support from Oliver Zeigermann, we got the >> code generation and runtime support working sufficiently to use the >> following grammars. generate some really nice code indeed. You will note >> that, except for the enhancement of the lexer modes, the grammars are >> backward compatible with v3 :) >> >> I still have a long way to go, but it's looking more & more useful (only >> does LL(1) code generation at this point). >> >> Ter >> --------------------------- >> lexer grammar HTMLLexer; >> >> TAG_START : '<' {pushMode(INSIDE);} ; >> >> COMMENT : '<!--' .* '-->' {skip();} ; >> >> TEXT : ~'<'+ ; >> >> mode INSIDE; >> >> TAG_STOP : '>' {popMode();} ; >> >> END_TAG : '/' ID '>' {popMode();} ; >> >> ID : ('A'..'Z'|'a'..'z'|'0'..'9'|'_'|'#')+ ; >> >> EQ : '=' ; >> >> STRING : '"' .* '"' >> ; >> >> WS : ' '+ {skip();} ; >> >> ------------------------ >> >> parser grammar HTMLParser; >> >> options { tokenVocab=HTMLLexer; } >> >> file : ( TAG_START (starttag | endtag) | TEXT)+ EOF ; >> >> starttag : ID attr* TAG_STOP ; >> >> attr : ID (EQ (ID|STRING))? ; >> >> endtag >> : END_TAG >> ; >> >> >> 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 [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.
