KEYWORDS list
    switch volatile case while do else const for if

IDENT regex
    [a-zA-Z_][0-9a-zA-Z_]*

INT regex
    [0-9]+

OPS list
    ( ) { } [ ] 
    ; ,
    - + ! % * & / << >> ^ |
    -= += != %= *= &= /= <<= == >>= ^= |=
    && || ++ --
    < <= > >= =
    . -> ? :