Character Classes

A “character” class describes a set of bytes.

Character classes may be named using definitions like this:

def $x = CHAR_CLASS

A character class may be used as a parser which matches a single byte, using the construct $[ CHAR_CLASS ]. Named character classes, such as $x or $any may be used directly as a byte parser (i.e., writing $[ $x ] is the same as just writing $x in a parser context).

byte literal	Match the literal exactly. For example 0, 'a', 0xFF, 0b11111111
"abc"	Match one of 'a', 'b', or 'c'
x	Match the byte corresponding to the value of x
$x	Match any byte matched by character class $x
$any	Match any byte
'0' .. '9'	Match bytes in the given range, inclusive
.. '9'	Match bytes less than or equal to '9'
'0' ..	Match bytes greater than or equal to '0'
$x | $y	Match byte that either match $x or $y
$x - $y	Match bytes that are in $x but not in $y
! $x	Match bytes that do not match chararcter class $x