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A “fragment” lexer rules does not result in creation of tokens and are only present for grammar simplification.
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Syntax
fragment NONCONTROL_CHAR: LETTER | DIGIT | SYMBOL | SPACE;
fragment LETTER: LOWER | UPPER;
fragment LOWER: 'a'..'z';
fragment UPPER: 'A'..'Z';
fragment DIGIT: '0'..'9';
fragment SPACE: ' ' | '\t';
fragment SYMBOL: '!' | '#'..'/' | ':'..'@' | '['..'`' | '{'..'~';