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authorGuido van Rossum <guido@python.org>1995-03-17 16:07:09 (GMT)
committerGuido van Rossum <guido@python.org>1995-03-17 16:07:09 (GMT)
commit470be14c8aa23a35a1f4d1f1260a66a85d3f3cd9 (patch)
tree4fd0b8eda81e63366598e55362ceac85adafccb4 /Doc/libimp.tex
parent7760cdea81166b7741561043c58dae171811fb2f (diff)
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mass changes; fix titles; add examples; correct typos; clarifications;
unified style; etc.
Diffstat (limited to 'Doc/libimp.tex')
-rw-r--r--Doc/libimp.tex38
1 files changed, 16 insertions, 22 deletions
diff --git a/Doc/libimp.tex b/Doc/libimp.tex
index 9ead176..91e250b 100644
--- a/Doc/libimp.tex
+++ b/Doc/libimp.tex
@@ -1,4 +1,4 @@
-\section{Built-in module \sectcode{imp}}
+\section{Built-in Module \sectcode{imp}}
\bimodindex{imp}
\index{import}
@@ -9,7 +9,7 @@ functions:
\renewcommand{\indexsubitem}{(in module struct)}
\begin{funcdesc}{get_magic}{}
-Return the magic string used to recognize value byte-compiled code
+Return the magic string value used to recognize byte-compiled code
files (``\code{.pyc} files'').
\end{funcdesc}
@@ -22,15 +22,15 @@ string to pass to the built-in \code{open} function to open the file
(this can be \code{'r'} for text files or \code{'rb'} for binary
files), and \var{type} is the file type, which has one of the values
\code{PY_SOURCE}, \code{PY_COMPILED} or \code{C_EXTENSION}, defined
-below.
+below. (System-dependent values may also be returned.)
\end{funcdesc}
\begin{funcdesc}{find_module}{name\, \optional{path}}
Try to find the module \var{name} on the search path \var{path}. The
default \var{path} is \code{sys.path}. The return value is a triple
\code{(\var{file}, \var{pathname}, \var{description})} where
-\var{file} is an open file object positioned at the beginning
-corresponding to the file found, \var{pathname} is the pathname of the
+\var{file} is an open file object positioned at the beginning,
+\var{pathname} is the pathname of the
file found, and \var{description} is a triple as contained in the list
returned by \code{get_suffixes} describing the kind of file found.
\end{funcdesc}
@@ -134,33 +134,27 @@ The following function emulates the default import statement:
\begin{verbatim}
import imp
-from sys import modules
+import sys
def __import__(name, globals=None, locals=None, fromlist=None):
- # Fast path: let's see if it's already in sys.modules.
- # Two speed optimizations are worth mentioning:
- # - We use 'modules' instead of 'sys.modules'; this saves a
- # dictionary look-up per call.
- # - It's also faster to use a try-except statement than
- # to use modules.has_key(name) to check if it's there.
- try:
- return modules[name]
- except KeyError:
- pass
-
- # See if it's a built-in module
+ # Fast path: see if the module has already been imported.
+ if sys.modules.has_key(name):
+ return sys.modules[name]
+
+ # If any of the following calls raises an exception,
+ # there's a problem we con't handle -- let the caller handle it.
+
+ # See if it's a built-in module.
m = imp.init_builtin(name)
if m:
return m
- # See if it's a frozen module
+ # See if it's a frozen module.
m = imp.init_frozen(name)
if m:
return m
# Search the default path (i.e. sys.path).
- # If this raises an exception, the module is not found --
- # let the caller handle the exception.
fp, pathname, (suffix, mode, type) = imp.find_module(name)
# See what we got.
@@ -170,7 +164,7 @@ def __import__(name, globals=None, locals=None, fromlist=None):
if type == imp.PY_SOURCE:
return imp.load_source(name, pathname, fp)
if type == imp.PY_COMPILED:
- return imp.load_source(name, pathname, fp)
+ return imp.load_compiled(name, pathname, fp)
# Shouldn't get here at all.
raise ImportError, '%s: unknown module type (%d)' % (name, type)