On Apr 30, 2010, at 16:41:50, Terence Parr wrote: > > On Apr 30, 2010, at 4:27 PM, Graham Wideman wrote: >> This prompts me to wonder how debuggable these lexers will be? Currently a >> certain amount of troubleshooting of lexing/parsing can be done by >> inspecting the generated lexer source, single-stepping it and so on. >> >> If you move to encoding the lexer logic in bytecodes, does the generated >> lexer source become an inscrutable black box? Or is there still meaningful >> source code to examine, trace etc? > > Yup. The bytecode is actually easier to read than the java ;) > > lexer grammar L2; > A : 'ab'; > B : 'a'..'z'+ ; > I : '0'..'9'+ ; > > yields: > > 0000: split 9, 16, 29 // says 3 paths are possible > 0009: match8 'a' > 0011: match8 'b' > 0013: accept 4 > 0016: range8 'a', 'z' > 0019: split 16, 26 > 0026: accept 5 > 0029: range8 '0', '9' > 0032: split 29, 39 // go back or fall out of loop into accept state > 0039: accept 6
This is a Java-only parser generator, then, isn't it? -- Rick 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.
