[antlr-interest] Any clue for this internal error?

[Kirby Bohling]

That sure looks like you don't have a parser rule, only lexer rules.  I
believe this would work, but I don't have ANTLR handy to actually try it.

=======================================
grammar CL;

    INPUTS : 'A' | 'B' | 'C' | 'D' | 'E' | 'F';
    OUTPUTS : 'U' | 'V' | 'X' | 'Y' | 'Z';

    INPUT : 'i';
    OUTPUT : 'o';

    action: ( INPUT INPUTS ) | ( OUTPUT OUTPUTS );
=======================================

Kirby


On Tue, Aug 28, 2012 at 8:43 AM, Meng Tian <tomnebula at gmail.com> wrote:

> Hello
>
> I am new to ANTLR, and I try to start with a very simple grammar definition
> (as follows).
>
> =======================================
> grammar CL;
>
>     fragment INPUTS : 'A' | 'B' | 'C' | 'D' | 'E' | 'F';
>     fragment OUTPUTS : 'U' | 'V' | 'X' | 'Y' | 'Z';
>
>     fragment INPUT : 'i';
>     fragment OUTPUT : 'o';
>
>     ACTION : ( INPUT INPUTS ) | ( OUTPUT OUTPUTS );
> =======================================
>
> I was expecting that strings like "iA" and "oU" should be successfully
> recognized and given the "ACTION" token. But when I run "java
> org.antlr.Tool CL.g", I had the following error message:
>
> =======================================
> error(10):  internal error: CL.g : java.lang.ClassCastException:
> org.antlr.runtime.tree.CommonTree cannot be cast to
> org.antlr.tool.GrammarAST
> org.antlr.grammar.v3.CodeGenTreeWalker.rules(CodeGenTreeWalker.java:1467)
>
> org.antlr.grammar.v3.CodeGenTreeWalker.grammarSpec(CodeGenTreeWalker.java:1441)
> org.antlr.grammar.v3.CodeGenTreeWalker.grammar_(CodeGenTreeWalker.java:509)
> org.antlr.codegen.CodeGenerator.genRecognizer(CodeGenerator.java:421)
> org.antlr.Tool.generateRecognizer(Tool.java:655)
> org.antlr.Tool.process(Tool.java:468)
> org.antlr.Tool.main(Tool.java:93)
> =======================================
>
> I have no idea about this error. Any clue on this?
>
> Thank you.
>
>
> Regards,
> Meng
>
> List: http://www.antlr.org/mailman/listinfo/antlr-interest
> Unsubscribe:
> http://www.antlr.org/mailman/options/antlr-interest/your-email-address
>