[antlr-interest] Problem with lexical nondeterminism - ANTLR 2.7.7

[Harald Mueller]

> Harold your suggestion would work if it matches NUMBER 
> first but it was actually an APAC_NUMERIC_TICKER.  The match actually 
> happens the other way around.

What? Maybe I misunderstand you - but the following code lexes all strings like 123,aa as APAC_N_T, whereas strings 1234 etc. are lexed as numbers (without any need for any predicates - just standard left-factoring).
Isn't that what you wanted??

Regards

Harald

------------------------------

header {
	using System.IO;
}

options {
  language = "CSharp";
}

class WordLexer extends Lexer;

tokens {
   APAC_N_T;
}

{
  public static void Main() {
    using (TextReader tr = new StringReader("1 12 123 1234 12345 123456 1234567 1,aa 12,aa 123,aa 1234,aa 12345,aa 123456,aa 1234567,aa 123 aa")) {
      WordLexer wl = new WordLexer(tr);
      for (;;) {
        IToken t = wl.nextToken();
        if (t.Type == Token.EOF_TYPE) break;
        switch (t.Type) {
            case NUMBER: Console.Out.WriteLine(t.getText() + " -> NUMBER"); break;
            case APAC_N_T: Console.Out.WriteLine(t.getText() + " -> APAC_N_T"); break;
            case ID: Console.Out.WriteLine(t.getText() + " -> ID"); break;
            default: Console.Out.WriteLine(t.getText() + " -> other"); break;
        }
      }
    }
    Console.In.Read();
  }
}

NUMBER
    : ('0'..'9')+
      ( ',' . .   { _ttype = APAC_N_T; }
      |
      )
    ;
    
ID  : ('a'..'z')+
    ;

WS  : (' ' | '\n' | '\r')+  { _ttype = Token.SKIP;  }
    ;

/* Result:

1 -> NUMBER
12 -> NUMBER
123 -> NUMBER
1234 -> NUMBER
12345 -> NUMBER
123456 -> NUMBER
1234567 -> NUMBER
1,aa -> APAC_N_T
12,aa -> APAC_N_T
123,aa -> APAC_N_T
1234,aa -> APAC_N_T
12345,aa -> APAC_N_T
123456,aa -> APAC_N_T
1234567,aa -> APAC_N_T
123 -> NUMBER
aa -> ID
*/

-- 
Der GMX SmartSurfer hilft bis zu 70% Ihrer Onlinekosten zu sparen! 
Ideal für Modem und ISDN: http://www.gmx.net/de/go/smartsurfer