encoder.py

#!/usr/bin/env python3
"""Encoder -- Program 12 from "Marvel Super Heroes Computer Fun".

Faithful recreation of the type-in BASIC listing: a 5-row columnar
transposition cipher. Spaces become '*', the message is padded to a multiple
of 5 with '+-#$', then laid out in 5 rows of MM columns and read down each
column into 5-character blocks. Type one line of the message at a time
(uppercase) and press Enter; type STOP to finish.

    python encoder.py
"""
import os
import sys

PAD = "+-#$"
GREEN = "\033[32m"
RESET = "\033[0m"
CLEAR = "\033[2J\033[H"


def enable_ansi():
    if os.name == "nt":
        os.system("")


def encode(M):                                  # lines 190-370
    MM = "".join("*" if ch == " " else ch for ch in M)   # 200-220
    mm = len(MM) // 5                                     # 240
    if mm != len(MM) / 5:                                  # 250
        MM += PAD[:(mm + 1) * 5 - len(MM)]                 # 260
        mm += 1                                            # 270
    A = [""] * mm                                          # 130 (per-message reset)
    for I in range(5):                                     # 290
        for J in range(1, mm + 1):                         # 300
            A[J - 1] += MM[J - 1 + I * mm]                 # 310
    return " ".join(A)                                      # 350-370


def play():
    enable_ansi()
    sys.stdout.write(CLEAR + GREEN)
    print("ENTER SECRET MESSAGE")
    print()
    while True:
        try:
            line = input("? ").strip().upper()
        except (EOFError, KeyboardInterrupt):
            break
        if line == "STOP":                                  # 180
            break
        if not line:
            continue
        print()
        print("THE CODED MESSAGE:")
        print()
        print(encode(line))
        print()
        print()
    sys.stdout.write(RESET)


def main():
    play()


if __name__ == "__main__":
    try:
        main()
    except KeyboardInterrupt:
        sys.stdout.write(RESET + "\n")