--- rest25/tutorial/modules.rst	2008-12-19 16:58:06.000000000 +0900
+++ rest262/tutorial/modules.rst	2009-04-05 05:01:50.000000000 +0900
@@ -94,77 +94,116 @@
 
 This does not introduce the module name from which the imports are taken in the
 local symbol table (so in the example, ``fibo`` is not defined).
 
 There is even a variant to import all names that a module defines::
 
    >>> from fibo import *
    >>> fib(500)
    1 1 2 3 5 8 13 21 34 55 89 144 233 377
 
 This imports all names except those beginning with an underscore (``_``).
 
+.. note::
+
+   For efficiency reasons, each module is only imported once per interpreter
+   session.  Therefore, if you change your modules, you must restart the
+   interpreter -- or, if it's just one module you want to test interactively,
+   use :func:`reload`, e.g. ``reload(modulename)``.
+
+
+.. _tut-modulesasscripts:
+
+Executing modules as scripts
+----------------------------
+
+When you run a Python module with ::
+
+   python fibo.py <arguments>
+
+the code in the module will be executed, just as if you imported it, but with
+the ``__name__`` set to ``"__main__"``.  That means that by adding this code at
+the end of your module::
+
+   if __name__ == "__main__":
+       import sys
+       fib(int(sys.argv[1]))
+
+you can make the file usable as a script as well as an importable module,
+because the code that parses the command line only runs if the module is
+executed as the "main" file::
+
+   $ python fibo.py 50
+   1 1 2 3 5 8 13 21 34
+
+If the module is imported, the code is not run::
+
+   >>> import fibo
+   >>>
+
+This is often used either to provide a convenient user interface to a module, or
+for testing purposes (running the module as a script executes a test suite).
+
 
 .. _tut-searchpath:
 
 The Module Search Path
 ----------------------
 
 .. index:: triple: module; search; path
 
 When a module named :mod:`spam` is imported, the interpreter searches for a file
 named :file:`spam.py` in the current directory, and then in the list of
 directories specified by the environment variable :envvar:`PYTHONPATH`.  This
 has the same syntax as the shell variable :envvar:`PATH`, that is, a list of
 directory names.  When :envvar:`PYTHONPATH` is not set, or when the file is not
 found there, the search continues in an installation-dependent default path; on
 Unix, this is usually :file:`.:/usr/local/lib/python`.
 
-Actually, modules are searched in the list of directories given by the  variable
-``sys.path`` which is initialized from the directory  containing the input
-script (or the current directory), :envvar:`PYTHONPATH` and the installation-
-dependent default.  This allows Python programs that know what they're doing to
-modify or replace the  module search path.  Note that because the directory
-containing the script being run is on the search path, it is important that the
-script not have the same name as a standard module, or Python will attempt to
-load the script as a module when that module is imported. This will generally be
-an error.  See section :ref:`tut-standardmodules`, "Standard Modules," for more
-information.
+Actually, modules are searched in the list of directories given by the variable
+``sys.path`` which is initialized from the directory containing the input script
+(or the current directory), :envvar:`PYTHONPATH` and the installation- dependent
+default.  This allows Python programs that know what they're doing to modify or
+replace the module search path.  Note that because the directory containing the
+script being run is on the search path, it is important that the script not have
+the same name as a standard module, or Python will attempt to load the script as
+a module when that module is imported. This will generally be an error.  See
+section :ref:`tut-standardmodules` for more information.
 
 
 "Compiled" Python files
 -----------------------
 
 As an important speed-up of the start-up time for short programs that use a lot
 of standard modules, if a file called :file:`spam.pyc` exists in the directory
-where :file:`spam.py` is found, this is assumed to contain an already-"byte-
-compiled" version of the module :mod:`spam`. The modification time of the
-version of :file:`spam.py` used to create :file:`spam.pyc` is recorded in
+where :file:`spam.py` is found, this is assumed to contain an
+already-"byte-compiled" version of the module :mod:`spam`. The modification time
+of the version of :file:`spam.py` used to create :file:`spam.pyc` is recorded in
 :file:`spam.pyc`, and the :file:`.pyc` file is ignored if these don't match.
 
 Normally, you don't need to do anything to create the :file:`spam.pyc` file.
 Whenever :file:`spam.py` is successfully compiled, an attempt is made to write
 the compiled version to :file:`spam.pyc`.  It is not an error if this attempt
 fails; if for any reason the file is not written completely, the resulting
 :file:`spam.pyc` file will be recognized as invalid and thus ignored later.  The
 contents of the :file:`spam.pyc` file are platform independent, so a Python
 module directory can be shared by machines of different architectures.
 
 Some tips for experts:
 
 * When the Python interpreter is invoked with the :option:`-O` flag, optimized
   code is generated and stored in :file:`.pyo` files.  The optimizer currently
   doesn't help much; it only removes :keyword:`assert` statements.  When
-  :option:`-O` is used, *all* bytecode is optimized; ``.pyc`` files are ignored
-  and ``.py`` files are compiled to optimized bytecode.
+  :option:`-O` is used, *all* :term:`bytecode` is optimized; ``.pyc`` files are
+  ignored and ``.py`` files are compiled to optimized bytecode.
 
 * Passing two :option:`-O` flags to the Python interpreter (:option:`-OO`) will
   cause the bytecode compiler to perform optimizations that could in some rare
   cases result in malfunctioning programs.  Currently only ``__doc__`` strings are
   removed from the bytecode, resulting in more compact :file:`.pyo` files.  Since
   some programs may rely on having these available, you should only use this
   option if you know what you're doing.
 
 * A program doesn't run any faster when it is read from a :file:`.pyc` or
   :file:`.pyo` file than when it is read from a :file:`.py` file; the only thing
   that's faster about :file:`.pyc` or :file:`.pyo` files is the speed with which
   they are loaded.
@@ -174,54 +213,46 @@
   startup time of a script may be reduced by moving most of its code to a module
   and having a small bootstrap script that imports that module.  It is also
   possible to name a :file:`.pyc` or :file:`.pyo` file directly on the command
   line.
 
 * It is possible to have a file called :file:`spam.pyc` (or :file:`spam.pyo`
   when :option:`-O` is used) without a file :file:`spam.py` for the same module.
   This can be used to distribute a library of Python code in a form that is
   moderately hard to reverse engineer.
 
   .. index:: module: compileall
 
-* The module :mod:`compileall` (XXX reference: ../lib/module-compileall.html)
-  can create :file:`.pyc` files (or :file:`.pyo` files when :option:`-O` is used)
-  for all modules in a directory.
-
-  .. % 
+* The module :mod:`compileall` can create :file:`.pyc` files (or :file:`.pyo`
+  files when :option:`-O` is used) for all modules in a directory.
 
 
 .. _tut-standardmodules:
 
 Standard Modules
 ================
 
 .. index:: module: sys
 
 Python comes with a library of standard modules, described in a separate
-document, the Python Library Reference (XXX reference: ../lib/lib.html)
-("Library Reference" hereafter).  Some modules are built into the interpreter;
-these provide access to operations that are not part of the core of the language
-but are nevertheless built in, either for efficiency or to provide access to
-operating system primitives such as system calls.  The set of such modules is a
-configuration option which also depends on the underlying platform  For example,
-the :mod:`amoeba` module is only provided on systems that somehow support Amoeba
-primitives.  One particular module deserves some attention: :mod:`sys` (XXX
-reference: ../lib/module-sys.html), which is built into every  Python
-interpreter.  The variables ``sys.ps1`` and ``sys.ps2`` define the strings used
-as primary and secondary prompts:
-
-.. % 
-
-::
+document, the Python Library Reference ("Library Reference" hereafter).  Some
+modules are built into the interpreter; these provide access to operations that
+are not part of the core of the language but are nevertheless built in, either
+for efficiency or to provide access to operating system primitives such as
+system calls.  The set of such modules is a configuration option which also
+depends on the underlying platform For example, the :mod:`winreg` module is only
+provided on Windows systems. One particular module deserves some attention:
+:mod:`sys`, which is built into every Python interpreter.  The variables
+``sys.ps1`` and ``sys.ps2`` define the strings used as primary and secondary
+prompts::
 
    >>> import sys
    >>> sys.ps1
    '>>> '
    >>> sys.ps2
    '... '
    >>> sys.ps1 = 'C> '
    C> print 'Yuck!'
    Yuck!
    C>
 
 
@@ -241,25 +272,25 @@
 
 The :func:`dir` Function
 ========================
 
 The built-in function :func:`dir` is used to find out which names a module
 defines.  It returns a sorted list of strings::
 
    >>> import fibo, sys
    >>> dir(fibo)
    ['__name__', 'fib', 'fib2']
    >>> dir(sys)
    ['__displayhook__', '__doc__', '__excepthook__', '__name__', '__stderr__',
-    '__stdin__', '__stdout__', '_getframe', 'api_version', 'argv', 
+    '__stdin__', '__stdout__', '_getframe', 'api_version', 'argv',
     'builtin_module_names', 'byteorder', 'callstats', 'copyright',
     'displayhook', 'exc_clear', 'exc_info', 'exc_type', 'excepthook',
     'exec_prefix', 'executable', 'exit', 'getdefaultencoding', 'getdlopenflags',
     'getrecursionlimit', 'getrefcount', 'hexversion', 'maxint', 'maxunicode',
     'meta_path', 'modules', 'path', 'path_hooks', 'path_importer_cache',
     'platform', 'prefix', 'ps1', 'ps2', 'setcheckinterval', 'setdlopenflags',
     'setprofile', 'setrecursionlimit', 'settrace', 'stderr', 'stdin', 'stdout',
     'version', 'version_info', 'warnoptions']
 
 Without arguments, :func:`dir` lists the names you have defined currently::
 
    >>> a = [1, 2, 3, 4, 5]
@@ -274,25 +305,25 @@
 
 :func:`dir` does not list the names of built-in functions and variables.  If you
 want a list of those, they are defined in the standard module
 :mod:`__builtin__`::
 
    >>> import __builtin__
    >>> dir(__builtin__)
    ['ArithmeticError', 'AssertionError', 'AttributeError', 'DeprecationWarning',
     'EOFError', 'Ellipsis', 'EnvironmentError', 'Exception', 'False',
     'FloatingPointError', 'FutureWarning', 'IOError', 'ImportError',
     'IndentationError', 'IndexError', 'KeyError', 'KeyboardInterrupt',
     'LookupError', 'MemoryError', 'NameError', 'None', 'NotImplemented',
-    'NotImplementedError', 'OSError', 'OverflowError', 
+    'NotImplementedError', 'OSError', 'OverflowError',
     'PendingDeprecationWarning', 'ReferenceError', 'RuntimeError',
     'RuntimeWarning', 'StandardError', 'StopIteration', 'SyntaxError',
     'SyntaxWarning', 'SystemError', 'SystemExit', 'TabError', 'True',
     'TypeError', 'UnboundLocalError', 'UnicodeDecodeError',
     'UnicodeEncodeError', 'UnicodeError', 'UnicodeTranslateError',
     'UserWarning', 'ValueError', 'Warning', 'WindowsError',
     'ZeroDivisionError', '_', '__debug__', '__doc__', '__import__',
     '__name__', 'abs', 'apply', 'basestring', 'bool', 'buffer',
     'callable', 'chr', 'classmethod', 'cmp', 'coerce', 'compile',
     'complex', 'copyright', 'credits', 'delattr', 'dict', 'dir', 'divmod',
     'enumerate', 'eval', 'execfile', 'exit', 'file', 'filter', 'float',
     'frozenset', 'getattr', 'globals', 'hasattr', 'hash', 'help', 'hex',
@@ -319,80 +350,80 @@
 
 Suppose you want to design a collection of modules (a "package") for the uniform
 handling of sound files and sound data.  There are many different sound file
 formats (usually recognized by their extension, for example: :file:`.wav`,
 :file:`.aiff`, :file:`.au`), so you may need to create and maintain a growing
 collection of modules for the conversion between the various file formats.
 There are also many different operations you might want to perform on sound data
 (such as mixing, adding echo, applying an equalizer function, creating an
 artificial stereo effect), so in addition you will be writing a never-ending
 stream of modules to perform these operations.  Here's a possible structure for
 your package (expressed in terms of a hierarchical filesystem)::
 
-   Sound/                          Top-level package
+   sound/                          Top-level package
          __init__.py               Initialize the sound package
-         Formats/                  Subpackage for file format conversions
+         formats/                  Subpackage for file format conversions
                  __init__.py
                  wavread.py
                  wavwrite.py
                  aiffread.py
                  aiffwrite.py
                  auread.py
                  auwrite.py
                  ...
-         Effects/                  Subpackage for sound effects
+         effects/                  Subpackage for sound effects
                  __init__.py
                  echo.py
                  surround.py
                  reverse.py
                  ...
-         Filters/                  Subpackage for filters
+         filters/                  Subpackage for filters
                  __init__.py
                  equalizer.py
                  vocoder.py
                  karaoke.py
                  ...
 
 When importing the package, Python searches through the directories on
 ``sys.path`` looking for the package subdirectory.
 
 The :file:`__init__.py` files are required to make Python treat the directories
 as containing packages; this is done to prevent directories with a common name,
 such as ``string``, from unintentionally hiding valid modules that occur later
 on the module search path. In the simplest case, :file:`__init__.py` can just be
 an empty file, but it can also execute initialization code for the package or
 set the ``__all__`` variable, described later.
 
 Users of the package can import individual modules from the package, for
 example::
 
-   import Sound.Effects.echo
+   import sound.effects.echo
 
-This loads the submodule :mod:`Sound.Effects.echo`.  It must be referenced with
+This loads the submodule :mod:`sound.effects.echo`.  It must be referenced with
 its full name. ::
 
-   Sound.Effects.echo.echofilter(input, output, delay=0.7, atten=4)
+   sound.effects.echo.echofilter(input, output, delay=0.7, atten=4)
 
 An alternative way of importing the submodule is::
 
-   from Sound.Effects import echo
+   from sound.effects import echo
 
 This also loads the submodule :mod:`echo`, and makes it available without its
 package prefix, so it can be used as follows::
 
    echo.echofilter(input, output, delay=0.7, atten=4)
 
 Yet another variation is to import the desired function or variable directly::
 
-   from Sound.Effects.echo import echofilter
+   from sound.effects.echo import echofilter
 
 Again, this loads the submodule :mod:`echo`, but this makes its function
 :func:`echofilter` directly available::
 
    echofilter(input, output, delay=0.7, atten=4)
 
 Note that when using ``from package import item``, the item can be either a
 submodule (or subpackage) of the package, or some  other name defined in the
 package, like a function, class or variable.  The ``import`` statement first
 tests whether the item is defined in the package; if not, it assumes it is a
 module and attempts to load it.  If it fails to find it, an :exc:`ImportError`
 exception is raised.
@@ -401,67 +432,65 @@
 except for the last must be a package; the last item can be a module or a
 package but can't be a class or function or variable defined in the previous
 item.
 
 
 .. _tut-pkg-import-star:
 
 Importing \* From a Package
 ---------------------------
 
 .. index:: single: __all__
 
-Now what happens when the user writes ``from Sound.Effects import *``?  Ideally,
+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 Mac and Windows platforms, where the
+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.
 
-.. % The \code{__all__} Attribute
-
 The only solution is for the package author to provide an explicit index of the
 package.  The import statement uses the following convention: if a package's
 :file:`__init__.py` code defines a list named ``__all__``, it is taken to be the
 list of module names that should be imported when ``from package import *`` is
 encountered.  It is up to the package author to keep this list up-to-date when a
 new version of the package is released.  Package authors may also decide not to
 support it, if they don't see a use for importing \* from their package.  For
-example, the file :file:`Sounds/Effects/__init__.py` could contain the following
+example, the file :file:`sounds/effects/__init__.py` could contain the following
 code::
 
    __all__ = ["echo", "surround", "reverse"]
 
-This would mean that ``from Sound.Effects import *`` would import the three
-named submodules of the :mod:`Sound` package.
+This would mean that ``from sound.effects import *`` would import the three
+named submodules of the :mod:`sound` package.
 
-If ``__all__`` is not defined, the statement ``from Sound.Effects import *``
-does *not* import all submodules from the package :mod:`Sound.Effects` into the
-current namespace; it only ensures that the package :mod:`Sound.Effects` has
+If ``__all__`` is not defined, the statement ``from sound.effects import *``
+does *not* import all submodules from the package :mod:`sound.effects` into the
+current namespace; it only ensures that the package :mod:`sound.effects` has
 been imported (possibly running any initialization code in :file:`__init__.py`)
 and then imports whatever names are defined in the package.  This includes any
 names defined (and submodules explicitly loaded) by :file:`__init__.py`.  It
 also includes any submodules of the package that were explicitly loaded by
 previous import statements.  Consider this code::
 
-   import Sound.Effects.echo
-   import Sound.Effects.surround
-   from Sound.Effects import *
+   import sound.effects.echo
+   import sound.effects.surround
+   from sound.effects import *
 
 In this example, the echo and surround modules are imported in the current
-namespace because they are defined in the :mod:`Sound.Effects` package when the
+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.
 
 Remember, there is nothing wrong with using ``from Package import
 specific_submodule``!  In fact, this is the recommended notation unless the
 importing module needs to use submodules with the same name from different
 packages.
@@ -470,39 +499,39 @@
 Intra-package References
 ------------------------
 
 The submodules often need to refer to each other.  For example, the
 :mod:`surround` module might use the :mod:`echo` module.  In fact, such
 references are so common that the :keyword:`import` statement first looks in the
 containing package before looking in the standard module search path. Thus, the
 :mod:`surround` module can simply use ``import echo`` or ``from echo import
 echofilter``.  If the imported module is not found in the current package (the
 package of which the current module is a submodule), the :keyword:`import`
 statement looks for a top-level module with the given name.
 
-When packages are structured into subpackages (as with the :mod:`Sound` package
-in the example), there's no shortcut to refer to submodules of sibling packages
-- the full name of the subpackage must be used.  For example, if the module
-:mod:`Sound.Filters.vocoder` needs to use the :mod:`echo` module in the
-:mod:`Sound.Effects` package, it can use ``from Sound.Effects import echo``.
+When packages are structured into subpackages (as with the :mod:`sound` package
+in the example), you can use absolute imports to refer to submodules of siblings
+packages.  For example, if the module :mod:`sound.filters.vocoder` needs to use
+the :mod:`echo` module in the :mod:`sound.effects` package, it can use ``from
+sound.effects import echo``.
 
 Starting with Python 2.5, in addition to the implicit relative imports described
 above, you can write explicit relative imports with the ``from module import
 name`` form of import statement. These explicit relative imports use leading
 dots to indicate the current and parent packages involved in the relative
 import. From the :mod:`surround` module for example, you might use::
 
    from . import echo
-   from .. import Formats
-   from ..Filters import equalizer
+   from .. import formats
+   from ..filters import equalizer
 
 Note that both explicit and implicit relative imports are based on the name of
 the current module. Since the name of the main module is always ``"__main__"``,
 modules intended for use as the main module of a Python application should
 always use absolute imports.
 
 
 Packages in Multiple Directories
 --------------------------------
 
 Packages support one more special attribute, :attr:`__path__`.  This is
 initialized to be a list containing the name of the directory holding the
