[antlr-interest] [C#] Lexer Not Throwing Errors

[Justin Holewinski]

I forgot to add that if I instead use the Java target, I get lexer
exceptions thrown on invalid input.

On Tue, Apr 19, 2011 at 12:48 PM, Justin Holewinski <
justin.holewinski at gmail.com> wrote:

> I'm using the C# 3 port of Antlr (target and code generator) and I'm
> experiencing a lack of lexer errors being generated.  As a concrete example,
> consider the following grammar:
>
> grammar CSTest;
>
> public
> compilation_unit
>   : IDENTIFIER* EOF
>   ;
>
> IDENTIFIER
>   : (ID_PART) (ID_PART_OR_NUMBER)*
>   ;
>
> fragment
> ID_PART
>   : ('a'..'z' | 'A'..'Z' | '_')
>   ;
>
> fragment
> ID_PART_OR_NUMBER
>   : ID_PART
>   | '0'..'9'
>   ;
>
> WS
>   :  (' '|'\r'|'\t'|'\n') { /*Skip();*/ $channel=Hidden; }
>   ;
>
> The only production in this grammar should allow for an arbitrary sequence
> of identifiers, and it does.  However, it also accepts ALL input, including
> binary files and anything else I pipe into it.  Is the default in the C#
> target to silently ignore any lexing errors?  In my driver program, I am not
> seeing any throw exceptions when I call the compilation_unit rule.
>
> using System;
> using System.IO;
> using Antlr.Runtime;
>
>
> namespace CSTest {
>   public class Program {
>     public static void Main(string[] args) {
>       string filename;
>       filename = args[0];
>       if(!Path.IsPathRooted(filename)) {
>         filename = Path.Combine(Environment.CurrentDirectory, filename);
>       }
>       ICharStream input = new ANTLRFileStream(filename);
>       CSTestLexer lexer = new CSTestLexer(input);
>       CommonTokenStream tokens = new CommonTokenStream(lexer);
>       CSTestParser parser = new CSTestParser(tokens);
> try {
> parser.compilation_unit();
> }
> catch(RecognitionException re) {
>   Console.Out.WriteLine("EXCEPTION");
> Console.Out.WriteLine(re.StackTrace);
>  }
>
>     }
>
>   }
>
> }
>
> --
>
> Thanks,
>
> Justin Holewinski
>
>


-- 

Thanks,

Justin Holewinski