Pym-s

Python with a sweet functionnal taste

Pyms is a transpiler. It produces clean and reliable python modules from OCaml-like type definitions. Pym-s is mainly designed to make symbolic manipulations easier and safer in python3.

Python modules generated with Pym-s are annotated according to the PEP 484 making them well suited for use with modern linters or type checkers such as pyre. Future versions of Pym-s will also include an option to generate dynamic type verification.

Example :

# bintree.pyms

typedef binary_tree =
  | Node of int * binary_tree * binary_tree
  | Leaf of int

# main.py

from bintree import *

def count_leafs(bt : binary_tree):
  if isinstance(bt, Leaf):
    return 1
  else:
    _, child1, child2 = bt
    return count_leafs(child1) + count_leafs(child2)

# outputs 2
print(count_leafs(Node(0, Leaf(1), Leaf(2))))

The preceding exemple need to be compiled down to pure python prior to execution :

$ pyms -i bintree.pyms -o bintree.py
$ python3 main.py

Install

Installing Pyms requires opam and a working ocaml environnement. While waiting for Pyms to be published on Opam, it is still possible to install it easily.

To install ocaml and opam, please visit this link

If you just have opam installed :

git clone git@github.com:jdrprod/Pym-s.git
cd Pym-s
opam pin .
opam install .

If you already use dune :

git clone git@github.com:jdrprod/Pym-s.git
cd Pym-s
dune build @install
dune install