Polyglot Programming

One file. Many languages. One runtime won't tell you.

A CS lecture on polyglot files — single files that are simultaneously valid in multiple languages or formats.

Structure

examples/
  demo.c           C + Python polyglot (the main demo)
  bash_python.sh   Bash + Python polyglot

presentation/
  app.py           Flask slide deck server
  requirements.txt
  templates/
    index.html     12-slide terminal-aesthetic presentation

Running the demos

# C + Python polyglot
python examples/demo.c
gcc examples/demo.c -o demo && ./demo

# Bash + Python polyglot
bash    examples/bash_python.sh
python3 examples/bash_python.sh

Running the presentation

cd presentation
pip install -r requirements.txt
python app.py
# open http://localhost:5000

Navigate slides with arrow keys, Space, or the on-screen buttons.

Topics covered

1. What is a polyglot file?
2. How parsers work (ignored regions, skip directives)
3. HTML + CSS + JavaScript — the web is already polyglot
4. Binary polyglots — JPEG+ZIP, GIFAR, PDF+ZIP
5. The C+Python trick — #if 0 + triple-quoted strings
6. Live demo — examples/demo.c
7. Bash+Python — the quoted exec trick
8. polycompiler — Python+JS (github.com/evanzhoudev/polycompiler)
9. Why it matters — CTF, security, parser literacy, art
10. Exercises