sigtools documentation

sigtools is a Python package that improves on introspection tools available for determining function signatures. This is useful for libraries or tooling that want to know how a function can be called: Documentation generators, IDEs, and tools that adapt themselves to functions they are given.

sigtools provides:

• Utilities to boost introspection of callables’ signature

• Backports of Python 3’s keyword-only parameters for code that used to maintain both Python 2 and 3 compatibility.

• Utilities for combining functions, for instance for creating decorators

• A Sphinx extension to make use of improved signature introspection in sphinx.ext.autodoc

Guide

• Improved signature reporting
  • Using sigtools.signature
  • Introspection through decorators
  • Evaluating PEP 563 stringified annotations
  • Parameter provenance
  • Limitations of automatic signature discovery
  • Getting more help
• Improved signatures in sphinx.ext.autodoc documentation
• Keyword-only parameters

Reference

• API Reference
  • sigtools.specifiers: Decorators to enhance a callable’s signature
  • sigtools.wrappers: Combine multiple functions
  • sigtools.signatures: Signature object manipulation
  • sigtools.modifiers: Modify the effective signature of the decorated callable
  • sigtools.support: Utilities for use in interactive sessions and unit tests
  • sigtools.sphinxext: Extension to make Sphinx use signature objects
• Picking the appropriate arguments for forwards
  • Picking the appropriate forwards_to_* decorator
  • *args and **kwargs are forwarded directly if present
  • Passing positional arguments to the wrapped function
  • Passing named arguments to from the wrapper
  • When the outer function uses *args or **kwargs but doesn’t forward them to the inner function
  • When the outer function passes an arbitrary *args or **kwargs to the inner function
  • Summary

Installing

You can install sigtools using pip. If in an activated virtualenv, type:

pip install sigtools

If you wish to do a user-wide install:

pip install --user sigtools