1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
|
:mod:`importlib` -- An implementation of :keyword:`import`
==========================================================
.. module:: importlib
:synopsis: An implementation of the import machinery.
.. moduleauthor:: Brett Cannon <brett@python.org>
.. sectionauthor:: Brett Cannon <brett@python.org>
.. versionadded:: 3.1
Introduction
------------
The purpose of the :mod:`importlib` package is two-fold. One is to provide an
implementation of the :keyword:`import` statement (and thus, by extension, the
:func:`__import__` function) in Python source code. This provides an
implementaiton of :keyword:`import` which is portable to any Python
interpreter. This also provides a reference implementation which is easier to
read than one in a programming language other than Python.
Two, the components to implement :keyword:`import` can be exposed in this
package, making it easier for users to create their own custom objects (known
generically as importers) to participate in the import process. Details on
providing custom importers can be found in :pep:`302`.
.. seealso::
:ref:`import`
The language reference for the :keyword:`import` statement.
`Packages specification <http://www.python.org/doc/essays/packages.html>`__
Original specification of packages. Some semantics have changed since
the writing of this document (e.g. redirecting based on :keyword:`None`
in :data:`sys.modules`).
The :func:`.__import__` function
The built-in function for which the :keyword:`import` statement is
syntactic sugar for.
:pep:`235`
Import on Case-Insensitive Platforms
:pep:`263`
Defining Python Source Code Encodings
:pep:`302`
New Import Hooks.
:pep:`328`
Imports: Multi-Line and Absolute/Relative
:pep:`366`
Main module explicit relative imports
:pep:`3128`
Using UTF-8 as the Default Source Encoding
Functions
---------
.. function:: __import__(name, globals={}, locals={}, fromlist=list(), level=0)
An implementation of the built-in :func:`__import__` function. See the
built-in function's documentation for usage instructions.
.. function:: import_module(name, package=None)
Import a module. The *name* argument specifies what module to
import in absolute or relative terms
(e.g. either ``pkg.mod`` or ``..mod``). If the name is
specified in relative terms, then the *package* argument must be
set to the package which is to act as the anchor for resolving the
package name (e.g. ``import_module('..mod', 'pkg.subpkg')`` will import
``pkg.mod``).
The :func:`import_module` function acts as a simplifying wrapper around
:func:`__import__`. This means all semantics of the function are derived
from :func:`__import__`, including requiring the package where an import is
occuring from to already be imported (i.e., *package* must already be
imported).
:mod:`importlib.machinery` -- Importers and path hooks
------------------------------------------------------
.. module:: importlib.machinery
:synopsis: Importers and path hooks
This module contains the various objects that help :keyword:`import`
find and load modules.
.. class:: BuiltinImporter
:term:`Importer` for built-in modules. All known built-in modules are
listed in :data:`sys.builtin_module_names`.
Only class methods are defined by this class to alleviate the need for
instantiation.
.. classmethod:: find_module(fullname, path=None)
Class method that allows this class to be a :term:`finder` for built-in
modules.
.. classmethod:: load_module(fullname)
Class method that allows this class to be a :term:`loader` for built-in
modules.
.. class:: FrozenImporter
:term:`Importer` for frozen modules.
Only class methods are defined by this class to alleviate the need for
instantiation.
.. classmethod:: find_module(fullname, path=None)
Class method that allows this class to be a :term:`finder` for frozen
modules.
.. classmethod:: load_module(fullname)
Class method that allows this class to be a :term:`loader` for frozen
modules.
|
