ANTLR Lexer rules in v4 Simple rules
Example
Lexer rules define token types. Their name has to start with an uppercase letter to distinguish them from parser rules.
INTEGER: [0-9]+;
IDENTIFIER: [a-zA-Z_] [a-zA-Z_0-9]*;
OPEN_PAREN: '(';
CLOSE_PAREN: ')';
Basic syntax:
| Syntax | Meaning |
|---|---|
A | Match lexer rule or fragment named A |
A B | Match A followed by B |
(A|B) | Match either A or B |
'text' | Match literal "text" |
A? | Match A zero or one time |
A* | Match A zero or more times |
A+ | Match A one or more times |
[A-Z0-9] | Match one character in the defined ranges (in this example between A-Z or 0-9) |
'a'..'z' | Alternative syntax for a character range |
~[A-Z] | Negation of a range - match any single character not in the range |
. | Match any single character |
