A native, bidirectional bridge between ooRexx and Python 3, modelled after BSF4ooRexx. Binaries for Linux, macOS and Windows: releases (see Installing).

• ooRexx → Python: a Rexx program imports Python modules (numpy, matplotlib, the standard library...) and uses Python objects as Rexx objects (.py, .PyObject), with keyword arguments, Python's operators, iteration and exceptions; a Python list can be used as a Rexx Array, counting from 1 (~makeArrayProxy); and Rexx classes extend Python classes, whose methods they override (::class Worker subclass PyObject, .py~extend, as ooRexx/.NET's .net~extend).
• Python → ooRexx: a Python program creates ooRexx interpreters, runs Rexx code and uses Rexx objects as Python objects (oorexx.Interpreter, oorexx.RexxObject); Python functions can be ADDRESS environments, and Rexx's standard streams go through Python's (sys.stdout...), each line marked as Rexx's (REXXout>, as in BSF4ooRexx).
• Both ways at once, on any thread: Rexx calls Python, which calls back a Rexx object, which calls Python again.
• One build for every Python 3 from 3.9: the bridge uses Python's Stable ABI only, so the same binary works with 3.9, 3.10, 3.11, 3.12, 3.13, 3.14, 3.15 and later, with no virtual environments and no per-version builds.

np = .py~import("numpy")
m  = np~array(((1, 2), (3, 4)))
say m~sum m~shape                                -- 10 (2, 2)
say .py~round(np~linalg~det(m), 2)               -- -2.0

::requires "python.cls"

import oorexx

with oorexx.Interpreter() as rexx:
    print(rexx.eval("6 * 7"))                    # 42
    times = rexx.routine("use arg a, b; return a * b")
    print(times(6, 7))                           # 42

Status: prototype. Both directions work and are covered by automated tests (ooRexxUnit test groups and Python checks, every nutshell sample included), on Linux x86_64, macOS (arm64 and x86_64) and Windows x64, with CPython 3.9–3.15, against ooRexx 5.3.0 (trunk, r13379, also the minimum: docs/design.md, ooRexx versions). Every push runs them all with every Python on all four (GitHub Actions: .github/workflows/build.yml), except that on Windows the three thread stress tests run with 3.9 and 3.15 only; a tag or a manual run runs them with every Python there too. The design is still being discussed, and parts of the API may change.

Two books, in the format of ooRexx's own and built with its documentation tools, as PDF and HTML: ooRexx and Python: Reference (pythonref, in the style of ooRexx's rexxref: every class, method and routine, with syntax diagrams and small examples) and ooRexx and Python: Cookbook (pythoncookbook: the main concepts, one recipe per sample). Each release carries them; every push builds them (artifact oorexxpython-docs of the Actions run). Their sources are in docs/books.

You need ooRexx and Python on your computer, and then the bridge: on Windows, its installer program; on Linux and macOS, its zip, whose install.rex does the same. Either one puts the bridge into your ooRexx, tells your Pythons where it is and records which Python Rexx programs use: no environment variables to set.

1. ooRexx 5.3.0, r13379 or later (beta). Get it from SourceForge and check that rexx -v runs in a terminal. The bridge needs its logicalwrapper.cls (Python's bool in Rexx), new in r13278, and the fix for ooRexx bug #2122 (threads), in r13286, and ooRexx's .CommandHandler (RFE #882), and the fix for #2123 (conditions other than SYNTAX reach the bridge), in r13320, and RaiseConditionObject (RFE #883, a condition raised again as it is), in r13329, and the fixes for #2130 and #2132 (a raised condition keeps the call's value; no crash under threads), in r13344; r13379 is the revision the ooRexx bridges are built and tested on. 5.2.0, the current release, has none of them.
2. Python 3.9 or later, any version: the bridge is one binary for all of them. If you want the samples that use numpy, matplotlib and pandas, install them too: pip install numpy matplotlib pandas.
3. The bridge, from the releases page, under the newest version, as below for each system. Both ways check both directions at the end (ooRexx/Python: installed and OK).
4. Try it. The samples are in ooRexx's samples folder, under python. Go there and run one: rexx 01-hello.rex, or python 30-run-rexx.py (python3 on Linux and macOS). Their README lists them all.

• Python: from python.org or from the Microsoft Store (Python install manager). It need not be on the PATH.
• Download oorexxpython-VERSION-windows-x64.exe and run it. Windows may warn that the program is not signed ("Windows protected your PC": More info, Run anyway), as it does with ooRexx's own installer.
• It finds ooRexx (or asks for its folder) and the Pythons installed on the computer, and asks which of them will import oorexx and which one Rexx programs use; another Python can be given by its python.exe.
• It puts the samples in C:\Program Files\ooRexx\samples\python, the books in ooRexx's doc folder, and, in ooRexx's Start menu folder, the books (ooRexx Documentation), the samples' slide deck (ooRexx Samples) and "Uninstall ooRexx-Python". It can also be uninstalled from Settings > Apps. To update, run the new version's installer.
• Unattended: oorexxpython-VERSION-windows-x64.exe /S /PYTHON=C:\path\to\python.exe /D=C:\Program Files\ooRexx (/D last; several Pythons separated by ;; /REXXPYTHON= for the one Rexx uses; without /PYTHON, every Python it finds). What it did is in %TEMP%\oorexxpython-install.log.
• The zip works on Windows too, for a portable ooRexx or when you prefer the command line (below).

Download the zip for your system (linux-x64, macos-arm64 for Apple silicon, macos-x64 for Intel Macs, windows-x64), unzip it anywhere, open a terminal in the unzipped folder oorexxpython and run rexx install, as below. The samples are then in ooRexx's samples folder, and the unzipped folder is no longer needed: you can delete it.

• Python: your distribution's python3, with its shared library, which some distributions package apart. On Debian and Ubuntu, that is libpython3.X, X being your Python's (python3 --version): for example, sudo apt install libpython3.12. rexx install notices when it is missing, and says what to install.

• ooRexx installed from a package (in /usr or /usr/local) needs sudo, and sudo may find another python3 than yours, so name yours:

  cd /path/to/oorexxpython
  sudo rexx install --python $(which python3)

• The samples end up in /usr/local/share/ooRexx/samples/python (or /usr/share/..., where ooRexx is).

• Python: the installer from python.org, or Homebrew's (brew install python).

• An ooRexx in a system folder such as /usr/local needs sudo, naming your Python as on Linux:

  cd /path/to/oorexxpython
  sudo rexx install --python $(which python3)

• ooRexx in C:\Program Files\ooRexx (the default) needs an administrator: open the terminal as administrator (right-click on Command Prompt or Terminal, "Run as administrator"), then

  cd C:\path\to\oorexxpython
  rexx install --python C:\path\to\python.exe

  (without --python, the python on the PATH).

• The samples end up in C:\Program Files\ooRexx\samples\python.

An ooRexx unzipped from one of the portable builds, with its bin on the PATH, is installed into in the same way, without administrator rights: rexx install (or rexx install --python /path/to/python).

• rexx oorexxpython-uninstall status, from any folder, shows what was installed and where; rexx oorexxpython-uninstall removes exactly that.
• Updating: run the new version's rexx install (or installer); it replaces the old one.
• Another Python: rexx install --python /path/to/python, as many times as you like (each Python gets its own link to the bridge); --user puts the link in your user folder, which needs no administrator.
• Which Python Rexx uses: the one the installer recorded in oorexxpython.cfg, next to the bridge: the first --python (or the one named with --rexx-python); installing again keeps that choice unless --rexx-python names another. The environment variable ORX_PYTHON, when set, takes precedence. Its installed packages are the ones Rexx programs see.
• Without installing: the zip's own README.md says which environment variables to set instead.
• The newest build: every push to this repository builds the same zips, available for 90 days as artifacts oorexxpython-<platform> of its Actions run (you must be signed in to GitHub to download them).

To build the bridge yourself, or to work on it, you need Linux x86_64, macOS or Windows, with:

• a C++ compiler: g++; Xcode's command line tools on macOS; MSVC on Windows, with the scripts run from Git Bash in a developer command prompt's environment;
• curl, and uv (or pip, which setup-pythons.sh uses to install uv);
• an ooRexx 5.3.0, r13379 or later, with its API headers: an installed ooRexx (/usr/local), or one of ooRexx's portable builds from SourceForge with its bin/ on the PATH.

git clone https://github.com/JosepMariaBlasco/oorexxpython
oorexxpython/scripts/setup-pythons.sh        # CPython 3.9 ... 3.15, with uv
oorexxpython/scripts/build.sh                # the bridge, seconds
oorexxpython/samples/run-one.sh 01-hello.rex

Everything goes into the directory that contains your clone ($ORXPY_WORK, overridable), next to it:

build/        oorexx.abi3.so, librexxpython.so, python.cls
              (macOS: librexxpython.dylib; Windows: oorexx.pyd, rexxpython.dll)
pythons/      the CPython versions to test against
oorexxunit/   ooRexx's test framework (for the tests)

To use the bridge from your own programs:

• From Rexx: put the build directory on REXX_PATH and LD_LIBRARY_PATH (DYLD_LIBRARY_PATH on macOS), and say which Python to use with ORX_PYTHON (default: the python3 on the PATH; its installed packages are the ones Rexx sees): ORX_PYTHON=$(which python3) LD_LIBRARY_PATH=build REXX_PATH=build rexx prog.rex. On Windows the build directory goes on the PATH instead, and ORX_PYTHON defaults to the python on the PATH.
• From Python: put the build directory on PYTHONPATH and import oorexx: PYTHONPATH=build python3 prog.py. On Windows, ooRexx's bin directory must be on the PATH (or OOREXX_HOME set): the module finds rexx.dll there itself.

oorexxpython/scripts/setup-oorexxunit.sh     # ooRexxUnit, from ooRexx's SVN
# numpy, matplotlib and pandas in each Python, for Numpy.testGroup:
for v in 3.9 3.10 3.11 3.12 3.13 3.14 3.15; do
  uv pip install --python "$(uv python find $v)" --break-system-packages numpy matplotlib pandas
done
oorexxpython/tests/run.sh                    # every test with every Python, ~1 min

run.sh runs each test file in its own process under a timeout (a deadlock is a failure). PYTHONS="3.9 3.13" and TESTS=Threads.testGroup choose; ORXPY_THREADS="16 16 2000" makes the threads stress test heavy. UV_PYTHON_INSTALL_DIR defaults to $ORXPY_WORK/pythons, where setup-pythons.sh installs them.

• src/ — the bridge.
  • bridge.cpp — oorexx.abi3.so: both directions, the proxies, the locks, ADDRESS (Stable ABI only, ooRexx's public native API only).
  • loader.cpp — librexxpython.so, the ooRexx package that finds and loads a Python when Rexx starts, then hands over to the bridge.
  • python.cls — the Rexx side: .py, .PyObject, py.import & co.
• samples/ — short "nutshell" programs, one feature each, both ways; each shows the Python it replaces and its exact output (see its README).
• tests/ — run.sh; rexx/ (ooRexxUnit test groups: basics, booleans, callbacks, ADDRESS, numpy, lifetime, threads, subclassing, and all the samples), python/ (the Python side), probe/ (the conversion probe and its expected output, run by python/t80_conversion_probe.py).
• scripts/ — build.sh, setup-pythons.sh, setup-oorexxunit.sh, setup-oorexx-deb.sh (installs SourceForge's ooRexx package for Ubuntu 24.04 at the CI's revision, OOREXX_REV in the workflow), and setup-oorexx.sh (builds ooRexx from SVN, for a revision with no package).
• docs/design.md — how the bridge works and why: names, values, keyword arguments, threads and locks, lifetime.
• docs/books/ — two books in the format of ooRexx's own, built with its documentation tools: Reference (pythonref, in the style of rexxref) and Cookbook (pythoncookbook, one recipe per sample); see its README.
• notes/oorexx-bugs.md — the ooRexx bugs the bridge's tests found, and what the code does about each.

The bridge was suggested by Rony G. Flatscher, author of BSF4ooRexx, the ooRexx–Java bridge it is modelled after; the .JSObject bridge of ooRexx/WASM is its sister. The tests use ooRexxUnit, ooRexx's own test framework (CPL 1.0), fetched from ooRexx's SVN, not included here. tests/python/t70_identity_lifetime.py asks of this bridge what Tom Dyer's qualification probes for his ooRexx/Python proof of concept in Alchemy ask of his, contributed by him under the Apache License 2.0; oorexx.RexxError's attributes follow his bridge's.

Written by Josep Maria Blasco, with Claude (Anthropic) as coding assistant.

Apache License 2.0 (LICENSE).