Hex.len constructor
Constrains the input data to the hexadecimal digits 0-9A–F
and its
length (number of digits) to len
hex-digits.
len
the number of hex-digits; it must be > 0.
mal
the error message if non-hex characters are found; if omitted, the
default value is 'non-hex-digit character(s) found'.
diff
the error message if the number of hex-digits is different from
len
.
Implementation
Hex.len(int len, {String? mal, String? diff})
: assert(len > 0),
_valHex = _HexImpl(mal, Len(len, diff: diff).call).call;