(){};,+-*!===<=>=!=<>/.

// expect: LEFT_PAREN ( null
// expect: RIGHT_PAREN ) null
// expect: LEFT_BRACE { null
// expect: RIGHT_BRACE } null
// expect: SEMICOLON ; null
// expect: COMMA , null
// expect: PLUS + null
// expect: MINUS - null
// expect: STAR * null
// expect: BANG_EQUAL != null
// expect: EQUAL_EQUAL == null
// expect: LESS_EQUAL <= null
// expect: GREATER_EQUAL >= null
// expect: BANG_EQUAL != null
// expect: LESS < null
// expect: GREATER > null
// expect: SLASH / null
// expect: DOT . null
// expect: EOF  null