(yet another) Python Lisp

See fredrikmeyer.net/pylisp/ for a literate style documentation.

Installation

Run pip install --editable .. There are no dependencies.

Run tests with pytest, and linting with flake8 .

Usage

>  python pylisp/repl.py
Welcome to pylisp.
>((lambda (x) (+ 2 x)) 5)
7.0
>

Or pipe text:

> echo '(+ 1 2)' | plsp
3.0

Factorial function

> python pylisp/repl.py
Welcome to pylisp.
>(define f (lambda (x) (if (< x 2) x (* x (f (dec x))))))
>(f 7)
5040.0

Built-ins

• lambda
• define
• +, and *, <, =, dec
• if
• doc (docstring for built-ins)
• car

Want to Have

• Multiple args
• Simple math functions. Maybe import from Python?
• Quotes
• Macros
• Read from file

Installing Python

I use pyenv to manage Python versions.

Install Python 3.11.1:

pyenv install 3.11.1

Build Docs

Docs are built with pycco. Build them by running pip install pycco and pycco pylisp/*.py. I use a simple search-replace to make eval.py the index page.

Similar projects

• pavpanchekha/pylisp.
• Peter Norvig: (How to Write a (Lisp) Interpreter (in Python)).
• (An ((Even Better) Lisp) Interpreter (in Python))
• lithp by fogus. Written in perhaps more idiomatic Python.