python

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python

Index

• Intro
• Dependencies
• Test dependencies
• Foreign dependencies
• API
• Examples
• Author(s)
• Maintainer(s)
• Version
• License
• Tags

Intro

This package provides an experimental interface to Python 3, based on Ivan Raikov's package for CHICKEN Scheme.

Dependencies

None from Cyclone, but it needs python3-dev or similar. In Debian Linux you should run:

$ sudo apt install python3-dev

Test-dependencies

None

Foreign-dependencies

None

API

The API provides a set of high-level procedures and another with low-level ones. Only high-level procedures are documented here.

(cyclone python)

[procedure] (py-start)

Mandatory to run it before any other procedure from this package. Run only once.

[procedure] (py-stop)

Mandatory to run after any other procedure from this package to avoid memory leaking. Run only once.

[procedure] (py-run-simple-string code)

This is the simplest way to run Python code. We can, for example, run:

(py-run-simple-string "print(1+2)")
;; => 3

But note that this procedure does not return data. Use py-value or py bellow to get the return value in Scheme format.

[procedure] (py-run-file file)

If we already have a Python project, we can use this procedure to run it. See the run-file.scm example.

[procedure] (py-value var)

Evaluates var and returns it. See the test file for example of usage.

[syntax] (py-def name [arg1 ...])

This macro converts a Python procedure into a Scheme one. The name can be a string or a list (not quoted) with a string (the Python procedure name) and a symbol (the Scheme name for the procedure). arg1 is optional.

[syntax] (py-def-method name [arg1])

This macro converts a Python object method into a Scheme procedure.

The name can be a string or a list (not quoted) with a string (the Python method name) and a symbol (the Scheme name for the created procedure). arg1 is optional.

The generated procedure is called with the method's parent object as the first parameter and has a rest parameter, so other arguments can be passed.

See the h5py.scm and swriter.scm for examples.

[syntax] (py-def-attribute name)

This macro converts a Python object attribute into a Scheme procedure. If you want to set the attribute into a variable, use py-value instead.

The generated procedure is called with the attribute's parent object as the first parameter. If a second parameter is given, the attribute is set to it.

The name can be a string or a list (not quoted) containing a string (the Python attribute name) and a symbol (the Scheme name for the created procedure). arg1 is optional.

See the h5py.scm and swriter.scm for examples.

[procedure] (py-call module procedure-or-attribute [arg1 ...])

This is the quickest form to retrieve Python values from module procedures or attributes. See the test file for example of usage.

[syntax] (with-python command1 ...)

A wrapper around the high-level commands above that runs (py-start) and (py-stop) automatically.

(with-python
 (py-import "math")
 (py-value "math.pi"))

is equivalent to

(py-start)
(py-import "math")
(py-value "math.pi")
(py-stop)

Examples

See the examples directories.

Author(s)

• Ivan Raikov
• Arthur Maciel

Maintainer(s)

Arthur Maciel

Version

"0.3.0"

License

BSD

Tags

FFI

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