Work in progress.
All subcommands take a --py flag before it to specify the Python to use.
The Python command can be:
- Prefixed by a dash (e.g.
-3.6). This is passed directly to the Python launcher (pycommand) if available. - Treated as a path if containing path separators.
- A command to be looked up in PATH.
Examples:
# Runs "init" by invoking `py -2` as Python.
molt --py -2 init
# Runs "run" by invoking the specified executable.
molt --py /usr/bin/python run
# Runs "init" by looking up `python3.6` in PATH.
molt --py python3.6 initCreates a Python environment for the project. An environment is created in
./__pypackages__/<compatibility-tag>.
The compatibility tag is used to identify Python package compatibility, based on PEP 425. The strictest compatibility tag is used to identify a platform. The value of which for a given Python interpreter can be unambiguously determined by invoking Brett Cannon’s pep425 tool:
import pep425
print(next(pep425.sys_tags()))Install packages into the environment from molt.lock.json.
molt run <command> executes a command available in the environment. This is
NOT a regular executable call; Molt manages commands during package
installation, and resolve them at runtime to emulate Setuptools and pip’s
entry point scripts.
Note that only commands installed via entry points work with molt run.
Access the base interpreter. For example, molt --py=python3.6 py myscript.py
would use interpreter python3.6 to execute file myscript.py.
Generate molt.lock.json from the manidest.
List latest version (globally and compatible) of a package on the package index. Useful if you want to add a pinned package to the manifest, but don’t immediately know what version to use.
TODO.
See design/lock-file.md.
molt install from Pipfile.lock, poetry.lock, or requirements.txt is
supported. The former two have precedence over requirements.txt; behaviour is
undetermined if both are found. This is done by converting them to
molt.lock.json, and install from that.
Tip: The auto-generated molt.lock.json can be ignored locally by adding it to
the project’s .git/info/exclude, so you can use Molt to develop Pipenv or
Poetry projects without converting wholesale.
Locking into those files is not supported. You’ll need to use the respective tool to generate a new lock file.
Requires Cargo, and a Python interpreter with pip available. The Python
interpreter should be either available in PATH, discoverable by py, or set in
the environment variable MOLT_BUILD_PYTHON.
cargo build --release
This gives you a binary in target/release. Copy it somewhere in your PATH.
Rust requirements:
cargo clippy
cargo test
Python requirements:
flake8 python vendor
black python vendor
tox