Skip to main content

A toy programming language.

Project description



Peep is a toy programming language with small practical applications. This project helps me to learn more about complier and interpreter design and implementation. Peep's syntax is mostly based off C, with some minor modifications.

This repository consists of a complete compiler frontend (lexical analyzer, syntax analyzer, and semantic analyzer) and a working interpreter.

Getting Started (for Windows users)

This project is built with Python 3.6.0 so make sure you have Python installed in your system with version 3.6.0 or greater. Also Python must be added in PATH environment variable.

After you satisfy the Python requirement, open a command prompt and type the following command to install Peep:

pip install thepeep

Then type peep, have fun!

Language Overview

Peep is derived from C based on its syntax. It's similar to C in most ways except that the Peep programs' entry point is a block (a code enclosed in curly braces {...}) whereas C programs have a main function as its entry point.

Built-in variable types and literals

  • int An unbounded number (ie. 1, -35, 134)

  • float An unbounded number with a decimal point (ie. 3.14, 2.71)

  • bool It's allowed to take either true or false.

  • string A sequence of characters enclosed with double quotes (ie. "foobarbaz", "#@$*", "123456")


See Grammar file for a complete description of Peep.

Example Programs

Hello world program

    print("Hello World!");

Program to input and print your name

    string name;

    print("Enter your name:");
    print("Hello...\t" + name + "!");

Program to calculate lowest commom multiple of two numbers

    int a;
    int b;
    int maxn;

    print("Input two numbers:");
    scan(a); scan(b);

    if (a > b) {
        maxn = a;
    } else {
        maxn = b;

    int lcm = maxn;

    while (true) {
        if (lcm % a == 0 && lcm % b == 0) {

        lcm += maxn;

    print("Lowest commom multiple of two numbers are:");

To run one of the programs above, save the code in a file with .peep extension and then type the following command in the prompt (replace ____ with your file name):

python -i ____.peep

Technical Details



  • 02/08/2020: Organized files; Packaged this repository to PyPI

Things to Add for Next Version (not necessary in order)

  • Ternary operator
  • Global variables
  • Command line arguments
  • Option to customize IO
  • Functions
  • More built-in functions
  • Variable references
  • Explicit type casting
  • Arrays
  • Modules
  • Classes
  • Debugger
  • Interactive mode
  • Code generation
  • Code optimization


GNU General Public License v3.0


Please email me if you find any.

Project details

Release history Release notifications

This version


Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Files for thepeep, version 1.1.2
Filename, size File type Python version Upload date Hashes
Filename, size thepeep-1.1.2-py3-none-any.whl (29.7 kB) File type Wheel Python version py3 Upload date Hashes View hashes
Filename, size thepeep-1.1.2.tar.gz (13.8 kB) File type Source Python version None Upload date Hashes View hashes

Supported by

Elastic Elastic Search Pingdom Pingdom Monitoring Google Google BigQuery Sentry Sentry Error logging AWS AWS Cloud computing DataDog DataDog Monitoring Fastly Fastly CDN DigiCert DigiCert EV certificate StatusPage StatusPage Status page