Multiple dispatch
Project description
A relatively sane approach to multiple dispatch in Python.
There exists several implementations of multiple dispatch (see links below). This implementation is efficient, relatively complete, and performs static analysis to avoid common issues.
Example
>>> from multipledispatch import dispatch
>>> @dispatch(int, int)
... def add(x, y):
... return x + y
>>> @dispatch(object, object)
... def add(x, y):
... return "%s + %s" % (x, y)
>>> add(1, 2)
3
>>> add(1, 'hello')
'1 + hello'
What this does
Dispatches on all non-keyword arguments
Supports inheritance
Supports instance methods
Supports union types, e.g. (int, float)
Supports builtin abstract classes, e.g. Iterator, Number, ...
Caches for fast repeated lookup
Identifies possible ambiguities at function definition time
Provides hints to resolve ambiguities when they occur
What this doesn’t do
Vararg dispatch
@dispatch([int])
def add(*args):
...
Diagonal dispatch
a = arbitrary_type()
@dispatch(a, a)
def are_same_type(x, y):
return True
Respect namespaces
Installation and Dependencies
multipledispatch is on the Python Package Index (PyPI):
pip install multipledispatch
or
easy_install multipledispatch
multipledispatch supports Python 2.6+ and Python 3.2+ with a common codebase. It is pure Python and requires no dependencies beyond the standard library.
It is, in short, a light weight dependency.
License
New BSD. See License.
Links
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