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authorMichael Foord <fuzzyman@voidspace.org.uk>2009-09-13 17:07:46 (GMT)
committerMichael Foord <fuzzyman@voidspace.org.uk>2009-09-13 17:07:46 (GMT)
commitee2df0300933e8a21372baae01ad2cf2e60a0282 (patch)
tree45e2d450b81940d4e2bc35b4292d1536208518f6 /Doc/tutorial
parent668be589ef5700aa1d7fd29e9f0b528824804d07 (diff)
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Tutorial tweaks. Issue 6849.
Diffstat (limited to 'Doc/tutorial')
-rw-r--r--Doc/tutorial/modules.rst22
1 files changed, 10 insertions, 12 deletions
diff --git a/Doc/tutorial/modules.rst b/Doc/tutorial/modules.rst
index 42a52e5..6f51357 100644
--- a/Doc/tutorial/modules.rst
+++ b/Doc/tutorial/modules.rst
@@ -103,6 +103,10 @@ There is even a variant to import all names that a module defines::
This imports all names except those beginning with an underscore (``_``).
+Note that in general the practice of importing ``*`` from a module or package is
+frowned upon, since it often causes poorly readable code. However, it is okay to
+use it to save typing in interactive sessions.
+
.. note::
For efficiency reasons, each module is only imported once per interpreter
@@ -443,14 +447,9 @@ Importing \* From a Package
Now what happens when the user writes ``from sound.effects import *``? Ideally,
one would hope that this somehow goes out to the filesystem, finds which
-submodules are present in the package, and imports them all. Unfortunately,
-this operation does not work very well on Windows platforms, where the
-filesystem does not always have accurate information about the case of a
-filename. On these platforms, there is no guaranteed way to know whether a file
-:file:`ECHO.PY` should be imported as a module :mod:`echo`, :mod:`Echo` or
-:mod:`ECHO`. (For example, Windows 95 has the annoying practice of showing all
-file names with a capitalized first letter.) The DOS 8+3 filename restriction
-adds another interesting problem for long module names.
+submodules are present in the package, and imports them all. This could take a
+long time and importing sub-modules might have unwanted side-effects that should
+only happen when the sub-module is explicitly imported.
The only solution is for the package author to provide an explicit index of the
package. The :keyword:`import` statement uses the following convention: if a package's
@@ -485,10 +484,9 @@ current namespace because they are defined in the :mod:`sound.effects` package
when the ``from...import`` statement is executed. (This also works when
``__all__`` is defined.)
-Note that in general the practice of importing ``*`` from a module or package is
-frowned upon, since it often causes poorly readable code. However, it is okay to
-use it to save typing in interactive sessions, and certain modules are designed
-to export only names that follow certain patterns.
+Although certain modules are designed to export only names that follow certain
+patterns when you use ``import *``, it is still considered bad practise in
+production code.
Remember, there is nothing wrong with using ``from Package import
specific_submodule``! In fact, this is the recommended notation unless the