mirror of https://github.com/exaloop/codon
67 lines
1.6 KiB
ReStructuredText
67 lines
1.6 KiB
ReStructuredText
Calling Python from Seq
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=======================
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Calling Python from Seq is possible in two ways:
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- ``from python import`` allows importing and calling Python functions from existing Python modules.
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- ``@python`` allows writing Python code directly in Seq.
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In order to use these features, the ``SEQ_PYTHON`` environment variable must be set to the appropriate
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Python shared library:
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.. code-block:: bash
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export SEQ_PYTHON=/path/to/libpython.X.Y.so
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For example, with a ``brew``-installed Python 3.9 on macOS, this might be
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.. code-block:: bash
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/usr/local/opt/python@3.9/Frameworks/Python.framework/Versions/3.9/lib/libpython3.9.dylib
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Note that only Python versions 3.6 and later are supported.
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``from python import``
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----------------------
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Let's say we have a Python function defined in *mymodule.py*:
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.. code-block:: python
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def multiply(a, b):
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return a * b
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We can call this function in Seq using ``from python import`` and indicating the appropriate
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call and return types:
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.. code-block:: seq
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from python import mymodule.multiply(int, int) -> int
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print(multiply(3, 4)) # 12
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(Be sure the ``PYTHONPATH`` environment variable includes the path of *mymodule.py*!)
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``@python``
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-----------
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Seq programs can contain functions that will be executed by Python via ``pydef``:
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.. code-block:: seq
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@python
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def multiply(a: int, b: int) -> int:
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return a * b
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print(multiply(3, 4)) # 12
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This makes calling Python modules like NumPy very easy:
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.. code-block:: seq
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@python
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def myrange(n: int) -> List[int]:
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from numpy import arange
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return list(arange(n))
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print(myrange(5)) # [0, 1, 2, 3, 4]
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