3.13 組み込みモジュール imp

  

本モジュールは、import文の実装に使用されているメカニズムへの インターフェースを提供します。以下の定数と関数を定義しています：

get_magic ()

コンパイルされたバイトコードファイル(``.pyc files'')を識別 するために使用されるmagic stringの値を返します。 （この値はパイソンのバージョンごとに異なる可能性があります。）

get_suffixes ()

モジュール固有の特徴を表す3つの要素からなるリストを返します。 各々の要素は、(suffix（拡張子）, mode（モード）, type（タイプ）)から構成されます。 suffixは、モジュール検索のためのファイル名を構成するときに、 モジュール名に付加する文字列です。 modeは、ファイルオープンを行う組み込み関数 openの引数として指定するオープンモードの文字列です （テキストファイルの場合は'r'、バイナリファイルの場合は 'rb'となります）。 typeは、ファイルタイプであり、PY_SOURCE、 PY_COMPILED、またはC_EXTENSIONのいずれかになります。 ファイルタイプの詳細は下を参照下さい。

find_module (name[, path])

検索パスpath上のnameという名のモジュールを検索します。 pathがディレクトリ名のリストであるとき、 それぞれのディレクトリから上記のget_suffixes()から取得される 拡張子を付加したファイルを検索します。 リスト内に不適切なディレクトリ名がある場合には無視されます （ただしリストの要素は全て文字列である必要があります）。 pathが指定されないか Noneのときには、 sys.pathによって与えられるディレクトリ名のリストが検索対象 となります。しかしこの場合には、最初に2,3の特別な場所を検索します。： it tries to find a built-in module with the given name (C_BUILTIN), then a frozen module (PY_FROZEN), and on some systems some other places are looked in as well (on the Mac, it looks for a resource (PY_RESOURCE); on Windows, it looks in the registry which may point to a specific file).

If search is successful, the return value is a triple (file, pathname, description) where file is an open file object positioned at the beginning, pathname is the pathname of the file found, and description is a triple as contained in the list returned by get_suffixes() describing the kind of module found. If the module does not live in a file, the returned file is None, filename is the empty string, and the description tuple contains empty strings for its suffix and mode; the module type is as indicate in parentheses dabove. If the search is unsuccessful, ImportError is raised. Other exceptions indicate problems with the arguments or environment.

This function does not handle hierarchical module names (names containing dots). In order to find P.M, i.e., submodule M of package P, use find_module() and load_module() to find and load package P, and then use find_module() with the path argument set to P.__path__. When P itself has a dotted name, apply this recipe recursively.

load_module (name, file, filename, description)

Load a module that was previously found by find_module() (or by an otherwise conducted search yielding compatible results). This function does more than importing the module: if the module was already imported, it is equivalent to a reload() ! The name argument indicates the full module name (including the package name, if this is a submodule of a package). The file argument is an open file, and filename is the corresponding file name; these can be None and '', respectively, when the module is not being loaded from a file. The description argument is a tuple as returned by find_module() describing what kind of module must be loaded.

If the load is successful, the return value is the module object; otherwise, an exception (usually ImportError) is raised.

Important: the caller is responsible for closing the file argument, if it was not None, even when an exception is raised. This is best done using a try ... finally statement.

new_module (name)

Return a new empty module object called name. This object is not inserted in sys.modules.

The following constants with integer values, defined in this module, are used to indicate the search result of find_module().

PY_SOURCE

The module was found as a source file.

PY_COMPILED

The module was found as a compiled code object file.

C_EXTENSION

The module was found as dynamically loadable shared library.

PY_RESOURCE

The module was found as a Macintosh resource. This value can only be returned on a Macintosh.

PKG_DIRECTORY

The module was found as a package directory.

C_BUILTIN

The module was found as a built-in module.

PY_FROZEN

The module was found as a frozen module (see init_frozen()).

The following constant and functions are obsolete; their functionality is available through find_module() or load_module(). They are kept around for backward compatibility:

SEARCH_ERROR

Unused.

init_builtin (name)

Initialize the built-in module called name and return its module object. If the module was already initialized, it will be initialized again. A few modules cannot be initialized twice -- attempting to initialize these again will raise an ImportError exception. If there is no built-in module called name, None is returned.

init_frozen (name)

Initialize the frozen module called name and return its module object. If the module was already initialized, it will be initialized again. If there is no frozen module called name, None is returned. (Frozen modules are modules written in Python whose compiled byte-code object is incorporated into a custom-built Python interpreter by Python's freeze utility. See "Tools/freeze/" for now.)

is_builtin (name)

Return 1 if there is a built-in module called name which can be initialized again. Return -1 if there is a built-in module called name which cannot be initialized again (see init_builtin()). Return 0 if there is no built-in module called name.

is_frozen (name)

Return 1 if there is a frozen module (see init_frozen()) called name, or 0 if there is no such module.

load_compiled (name, pathname, file)

Load and initialize a module implemented as a byte-compiled code file and return its module object. If the module was already initialized, it will be initialized again. The name argument is used to create or access a module object. The pathname argument points to the byte-compiled code file. The file argument is the byte-compiled code file, open for reading in binary mode, from the beginning. It must currently be a real file object, not a user-defined class emulating a file.

load_dynamic (name, pathname[, file])

Load and initialize a module implemented as a dynamically loadable shared library and return its module object. If the module was already initialized, it will be initialized again. Some modules don't like that and may raise an exception. The pathname argument must point to the shared library. The name argument is used to construct the name of the initialization function: an external C function called "initname()" in the shared library is called. The optional file argment is ignored. (Note: using shared libraries is highly system dependent, and not all systems support it.)

load_source (name, pathname, file)

Load and initialize a module implemented as a Python source file and return its module object. If the module was already initialized, it will be initialized again. The name argument is used to create or access a module object. The pathname argument points to the source file. The file argument is the source file, open for reading as text, from the beginning. It must currently be a real file object, not a user-defined class emulating a file. Note that if a properly matching byte-compiled file (with suffix ".pyc") exists, it will be used instead of parsing the given source file.