szyfrow/support/text_prettify.py

   1 """Various functions for prettifying text, useful when cipher routines generate
   2 strings of letters without spaces.
   3 """
   4
   5 import string
   6 from szyfrow.support.segment import segment
   7 from szyfrow.support.utilities import cat, lcat, sanitise
   8
   9
  10 def prettify(text, width=100):
  11     """Segment a text into words, then pack into lines, and combine the lines
  12     into a single string for printing."""
  13     return lcat(tpack(segment(text), width=width))
  14
  15
  16 def tpack(text, width=100):
  17     """Pack a list of words into lines, so long as each line (including
  18     intervening spaces) is no longer than _width_"""
  19     lines = [text[0]]
  20     for word in text[1:]:
  21         if len(lines[-1]) + 1 + len(word) <= width:
  22             lines[-1] += (' ' + word)
  23         else:
  24             lines += [word]
  25     return lines
  26
  27
  28 def depunctuate_character(c):
  29     """Record the punctuation of a character"""
  30     if c in string.ascii_uppercase:
  31         return 'UPPER'
  32     elif c in string.ascii_lowercase:
  33         return 'LOWER'
  34     else:
  35         return c
  36
  37
  38 def depunctuate(text):
  39     """Record the punctuation of a string, so it can be applied to a converted
  40     version of the string.
  41
  42     For example,
  43     punct = depunctuate(ciphertext)
  44     plaintext = decipher(sanitise(ciphertext))
  45     readable_plaintext = repunctuate(plaintext, punct)
  46     """
  47     return [depunctuate_character(c) for c in text]
  48
  49
  50 def repunctuate_character(letters, punctuation):
  51     """Apply the recorded punctuation to a character. The letters must be
  52     an iterator of base characters."""
  53     if punctuation == 'UPPER':
  54         return next(letters).upper()
  55     elif punctuation == 'LOWER':
  56         return next(letters).lower()
  57     else:
  58         return punctuation
  59
  60
  61 def repunctuate(text, punctuation):
  62     """Apply the recored punctuation to a sanitised string.
  63
  64     For example,
  65     punct = depunctuate(ciphertext)
  66     plaintext = decipher(sanitise(ciphertext))
  67     readable_plaintext = repunctuate(plaintext, punct)
  68     """
  69     letters = iter(sanitise(text))
  70     return cat(repunctuate_character(letters, p) for p in punctuation)