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copied!<p>You must realize that the lexer does <em>not</em> produce tokens based on what the parser tries to match. So, in your case, the input <code>"5"</code> will always be tokenized as a <code>RANGE1_VALUES</code> and never as a <code>RANGE2_VALUES</code> because both <code>RANGE1_VALUES</code> and <code>RANGE2_VALUES</code> can match this input but <code>RANGE1_VALUES</code> comes first (so <code>RANGE1_VALUES</code> takes precedence over <code>RANGE2_VALUES</code>).</p> <p>A possible fix would be to remove both <code>RANGE1_VALUES</code> and <code>RANGE2_VALUES</code> rules and replace them with the following lexer rules:</p> <pre><code>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') ; </code></pre> <p>and the introduce these new parser rules:</p> <pre><code>range1_values : D0_4 | D5 | D6_50 ; range2_values : A_B_C | D5 ; </code></pre> <p>and change all <code>RANGE1_VALUES</code> and <code>RANGE2_VALUES</code> calls in your parser rules with <code>range1_values</code> and <code>range2_values</code> respectively.</p> <h2>EDIT</h2> <p>Instead of trying to solve this at the <em>lexer-level</em>, 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 <em><a href="https://stackoverflow.com/questions/3056441/what-is-a-semantic-predicate-in-antlr">semantic predicate</a></em>:</p> <pre><code>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' ; </code></pre>

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