'''
Helpful string constants.
'''

let ascii_lowercase = 'abcdefghijklmnopqrstuvwxyz'
let ascii_uppercase = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
let ascii_letters = ascii_lowercase + ascii_uppercase

let digits = '0123456789'
let hexdigits = digits + 'abcdefABCDEF'
let octdigits = '01234567'

let punctuation = '!"#$%&\'()*+,-./:;<=>?@[\\]^_`{|}~'
let whitespace = '\t\n\x0b\x0c\r '
let printable = digits + ascii_letters + punctuation + whitespace