ANTLR3 common values in 2 different domain values

I need to define a language-parser for the following search criteria:

CRITERIA_1=<values-set-#1> AND/OR CRITERIA_2=<values-set-#2>;

Where <values-set-#1> can have values from 1-50 and <values-set-#2> can be from the following set (5, A, B, C) - case is not important here.

I have decided to use ANTLR3 (v3.4) with output in C# (CSharp3) and it used to work pretty smooth until now. The problem is that it fails to parse the string when I provide values from both data-sets (I.e. in this case '5'). For example, if I provide the following string

CRITERIA_1=5;

It returns the following error where the value node was supposed to be:

<unexpected: [@1,11:11='5',<27>,1:11], resync=5>

The grammar definition file is the following:

grammar ZeGrammar;

options {
    language=CSharp3;
    TokenLabelType=CommonTok开发者_JAVA百科en;
    output=AST;
    ASTLabelType=CommonTree;
    k=3;
}

tokens 
{
    ROOT;
    CRITERIA_1;
    CRITERIA_2;
    OR = 'OR';
    AND = 'AND';
    EOF = ';';
    LPAREN = '(';
    RPAREN = ')';
}

public
start
  : expr EOF -> ^(ROOT expr)
  ;

expr
  : subexpr ((AND|OR)^ subexpr)*
  ;

subexpr
  :   grouppedsubexpr
    | 'CRITERIA_1=' rangeval1_expr -> ^(CRITERIA_1 rangeval1_expr)
    | 'CRITERIA_2=' rangeval2_expr -> ^(CRITERIA_2 rangeval2_expr)
  ;

grouppedsubexpr
  :  LPAREN! expr RPAREN!
  ;

rangeval1_expr
  :   rangeval1_subexpr
    | RANGE1_VALUES
  ;

rangeval1_subexpr
  : LPAREN! rangeval1_expr (OR^ rangeval1_expr)* RPAREN!
  ;

RANGE1_VALUES
  : (('0'..'4')? ('0'..'9') | '5''0')
  ;

rangeval2_expr
  :   rangeval2_subexpr
    | RANGE2_VALUES
  ;

rangeval2_subexpr
  : LPAREN! rangeval2_expr (OR^ rangeval2_expr)* RPAREN!
  ;

RANGE2_VALUES
  : '5' | ('a'|'A') | ('b'|'B') | ('c'|'C')
  ;

And if I remove the value '5' from RANGE2_VALUES it works fine. Can anyone hint me on what I am doing wrong?

You must realize that the lexer does not produce tokens based on what the parser tries to match. So, in your case, the input "5" will always be tokenized as a RANGE1_VALUES and never as a RANGE2_VALUES because both RANGE1_VALUES and RANGE2_VALUES can match this input but RANGE1_VALUES comes first (so RANGE1_VALUES takes precedence over RANGE2_VALUES).

A possible fix would be to remove both RANGE1_VALUES and RANGE2_VALUES rules and replace them with the following lexer rules:

D0_4
  :  '0'..'4'
  ;

D5
  :  '5'
  ;

D6_50
  :  '6'..'9'           // 6-9
  |  '1'..'4' '0'..'9'  // 10-49
  |  '50'               // 50
  ;

A_B_C
  :  ('a'|'A') 
  |  ('b'|'B') 
  |  ('c'|'C')
  ;

and the introduce these new parser rules:

range1_values
  :  D0_4
  |  D5
  |  D6_50
  ;

range2_values
  :  A_B_C
  |  D5
  ;

and change all RANGE1_VALUES and RANGE2_VALUES calls in your parser rules with range1_values and range2_values respectively.

EDIT

Instead of trying to solve this at the lexer-level, you might simply match any integer value and check inside the parser rule if the value is the correct one (or correct range) using a semantic predicate:

range1_values
  :  INT {Integer.valueOf($INT.text) <= 50}?
  ;

range2_values
  :  A_B_C
  |  INT {Integer.valueOf($INT.text) == 5}?
  ;

INT
  :  '0'..'9'+
  ;

A_B_C
  :  'a'..'c'
  |  'A'..'C'
  ;