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Docs/reference:Consistent spacing is a pre-requisite to consistently good writing. #136638

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198 changes: 99 additions & 99 deletions Doc/reference/compound_stmts.rst
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414 changes: 207 additions & 207 deletions Doc/reference/datamodel.rst
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62 changes: 31 additions & 31 deletions Doc/reference/executionmodel.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -19,9 +19,9 @@ Structure of a program
A Python program is constructed from code blocks.
A :dfn:`block` is a piece of Python program text that is executed as a unit.
The following are blocks: a module, a function body, and a class definition.
Each command typed interactively is a block. A script file (a file given as
Each command typed interactively is a block. A script file (a file given as
standard input to the interpreter or specified as a command line argument to the
interpreter) is a code block. A script command (a command specified on the
interpreter) is a code block. A script command (a command specified on the
interpreter command line with the :option:`-c` option) is a code block.
A module run as a top level script (as module ``__main__``) from the command
line using a :option:`-m` argument is also a code block. The string
Expand All @@ -30,7 +30,7 @@ code block.

.. index:: pair: execution; frame

A code block is executed in an :dfn:`execution frame`. A frame contains some
A code block is executed in an :dfn:`execution frame`. A frame contains some
administrative information (used for debugging) and determines where and how
execution continues after the code block's execution has completed.

Expand All @@ -52,7 +52,7 @@ Binding of names
single: name
pair: binding; name

:dfn:`Names` refer to objects. Names are introduced by name binding operations.
:dfn:`Names` refer to objects. Names are introduced by name binding operations.

.. index:: single: from; import statement

Expand Down Expand Up @@ -87,9 +87,9 @@ function definition or at the module level (the top-level code block).
.. index:: pair: free; variable

If a name is bound in a block, it is a local variable of that block, unless
declared as :keyword:`nonlocal` or :keyword:`global`. If a name is bound at
the module level, it is a global variable. (The variables of the module code
block are local and global.) If a variable is used in a code block but not
declared as :keyword:`nonlocal` or :keyword:`global`. If a name is bound at
the module level, it is a global variable. (The variables of the module code
block are local and global.) If a variable is used in a code block but not
defined there, it is a :term:`free variable`.

Each occurrence of a name in the program text refers to the :dfn:`binding` of
Expand All @@ -102,16 +102,16 @@ Resolution of names

.. index:: scope

A :dfn:`scope` defines the visibility of a name within a block. If a local
variable is defined in a block, its scope includes that block. If the
A :dfn:`scope` defines the visibility of a name within a block. If a local
variable is defined in a block, its scope includes that block. If the
definition occurs in a function block, the scope extends to any blocks contained
within the defining one, unless a contained block introduces a different binding
for the name.

.. index:: single: environment

When a name is used in a code block, it is resolved using the nearest enclosing
scope. The set of all such scopes visible to a code block is called the block's
scope. The set of all such scopes visible to a code block is called the block's
:dfn:`environment`.

.. index::
Expand All @@ -125,26 +125,26 @@ used, an :exc:`UnboundLocalError` exception is raised.
:exc:`UnboundLocalError` is a subclass of :exc:`NameError`.

If a name binding operation occurs anywhere within a code block, all uses of the
name within the block are treated as references to the current block. This can
lead to errors when a name is used within a block before it is bound. This rule
is subtle. Python lacks declarations and allows name binding operations to
occur anywhere within a code block. The local variables of a code block can be
name within the block are treated as references to the current block. This can
lead to errors when a name is used within a block before it is bound. This rule
is subtle. Python lacks declarations and allows name binding operations to
occur anywhere within a code block. The local variables of a code block can be
determined by scanning the entire text of the block for name binding operations.
See :ref:`the FAQ entry on UnboundLocalError <faq-unboundlocalerror>`
for examples.

If the :keyword:`global` statement occurs within a block, all uses of the names
specified in the statement refer to the bindings of those names in the top-level
namespace. Names are resolved in the top-level namespace by searching the
namespace. Names are resolved in the top-level namespace by searching the
global namespace, i.e. the namespace of the module containing the code block,
and the builtins namespace, the namespace of the module :mod:`builtins`. The
global namespace is searched first. If the names are not found there, the
and the builtins namespace, the namespace of the module :mod:`builtins`. The
global namespace is searched first. If the names are not found there, the
builtins namespace is searched next. If the names are also not found in the
builtins namespace, new variables are created in the global namespace.
The global statement must precede all uses of the listed names.

The :keyword:`global` statement has the same scope as a name binding operation
in the same block. If the nearest enclosing scope for a free variable contains
in the same block. If the nearest enclosing scope for a free variable contains
a global statement, the free variable is treated as a global.

.. XXX say more about "nonlocal" semantics here
Expand All @@ -158,7 +158,7 @@ cannot be rebound with the :keyword:`!nonlocal` statement.
.. index:: pair: module; __main__

The namespace for a module is automatically created the first time a module is
imported. The main module for a script is always called :mod:`__main__`.
imported. The main module for a script is always called :mod:`__main__`.

Class definition blocks and arguments to :func:`exec` and :func:`eval` are
special in the context of name resolution.
Expand Down Expand Up @@ -301,14 +301,14 @@ Builtins and restricted execution
.. impl-detail::

Users should not touch ``__builtins__``; it is strictly an implementation
detail. Users wanting to override values in the builtins namespace should
detail. Users wanting to override values in the builtins namespace should
:keyword:`import` the :mod:`builtins` module and modify its
attributes appropriately.

The builtins namespace associated with the execution of a code block
is actually found by looking up the name ``__builtins__`` in its
global namespace; this should be a dictionary or a module (in the
latter case the module's dictionary is used). By default, when in the
latter case the module's dictionary is used). By default, when in the
:mod:`__main__` module, ``__builtins__`` is the built-in module
:mod:`builtins`; when in any other module, ``__builtins__`` is an
alias for the dictionary of the :mod:`builtins` module itself.
Expand All @@ -331,11 +331,11 @@ This means that the following code will print 42::
.. XXX from * also invalid with relative imports (at least currently)

The :func:`eval` and :func:`exec` functions do not have access to the full
environment for resolving names. Names may be resolved in the local and global
namespaces of the caller. Free variables are not resolved in the nearest
enclosing namespace, but in the global namespace. [#]_ The :func:`exec` and
environment for resolving names. Names may be resolved in the local and global
namespaces of the caller. Free variables are not resolved in the nearest
enclosing namespace, but in the global namespace. [#]_ The :func:`exec` and
:func:`eval` functions have optional arguments to override the global and local
namespace. If only one namespace is specified, it is used for both.
namespace. If only one namespace is specified, it is used for both.

.. XXX(ncoghlan) above is only accurate for string execution. When executing code objects,
closure cells may now be passed explicitly to resolve co_freevars references.
Expand All @@ -356,15 +356,15 @@ Exceptions
single: error handling

Exceptions are a means of breaking out of the normal flow of control of a code
block in order to handle errors or other exceptional conditions. An exception
block in order to handle errors or other exceptional conditions. An exception
is *raised* at the point where the error is detected; it may be *handled* by the
surrounding code block or by any code block that directly or indirectly invoked
the code block where the error occurred.

The Python interpreter raises an exception when it detects a run-time error
(such as division by zero). A Python program can also explicitly raise an
(such as division by zero). A Python program can also explicitly raise an
exception with the :keyword:`raise` statement. Exception handlers are specified
with the :keyword:`try` ... :keyword:`except` statement. The :keyword:`finally`
with the :keyword:`try` ... :keyword:`except` statement. The :keyword:`finally`
clause of such a statement can be used to specify cleanup code which does not
handle the exception, but is executed whether an exception occurred or not in
the preceding code.
Expand All @@ -379,18 +379,18 @@ re-entering the offending piece of code from the top).
.. index:: single: SystemExit (built-in exception)

When an exception is not handled at all, the interpreter terminates execution of
the program, or returns to its interactive main loop. In either case, it prints
the program, or returns to its interactive main loop. In either case, it prints
a stack traceback, except when the exception is :exc:`SystemExit`.

Exceptions are identified by class instances. The :keyword:`except` clause is
Exceptions are identified by class instances. The :keyword:`except` clause is
selected depending on the class of the instance: it must reference the class of
the instance or a :term:`non-virtual base class <abstract base class>` thereof.
The instance can be received by the handler and can carry additional information
about the exceptional condition.

.. note::

Exception messages are not part of the Python API. Their contents may change
Exception messages are not part of the Python API. Their contents may change
from one version of Python to the next without warning and should not be
relied on by code which will run under multiple versions of the interpreter.

Expand Down
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