Decode the Swedish "Robber Language" into plain text.

robber.py

#! /usr/bin/env python3
"""Decode or encode the Swedish Robber Language.

Proof of concept by traal (Fredrik Mellström).
"""

import argparse
import re
import sys


DEFAULT_ROBBER_TEXT = "Rorövovarorsospoproråkoketot äror cocoololtot!"


def main():
    """Run the main script."""
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("-e", "--encode", action="store_true")
    parser.add_argument("text", nargs="*")
    args = parser.parse_args()

    description = "😊 -----> 🤠" if args.encode else "🤠 -----> 😊"

    for text in args.text or [DEFAULT_ROBBER_TEXT]:
        print(f"\n{text}\n{description}")
        print(robber(text) if args.encode else derobber(text))


CONSONANTS = "bcdfghjklmnpqrstvwxz"
ROBBER_RE = re.compile(
    rf"(?: ( [{CONSONANTS}] ) o \1 ) | (.)",
    re.VERBOSE | re.IGNORECASE | re.DOTALL,
)


def robber(plain_text: str) -> str:
    """Generate Robber Language."""
    return "".join((f"{x}o{x}" if x in CONSONANTS else x) for x in plain_text)


def derobber(robber_text: str) -> str:
    """Parse the Swedish Robber Language."""
    result = []
    for match in ROBBER_RE.findall(robber_text):
        if match:
            one, two = match
            result.append(one or two)

    return "".join(result)


if __name__ == "__main__":
    sys.exit(main())