Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

gh-56374: Clarify documentation of nonlocal #116942

Merged
merged 5 commits into from
Mar 19, 2024
Merged
Changes from all commits
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
30 changes: 17 additions & 13 deletions Doc/reference/simple_stmts.rst
Original file line number Diff line number Diff line change
Expand Up @@ -1006,25 +1006,29 @@ The :keyword:`!nonlocal` statement
.. productionlist:: python-grammar
nonlocal_stmt: "nonlocal" `identifier` ("," `identifier`)*

The :keyword:`nonlocal` statement causes the listed identifiers to refer to
previously bound variables in the nearest enclosing scope excluding globals.
This is important because the default behavior for binding is to search the
local namespace first. The statement allows encapsulated code to rebind
variables outside of the local scope besides the global (module) scope.

Names listed in a :keyword:`nonlocal` statement, unlike those listed in a
:keyword:`global` statement, must refer to pre-existing bindings in an
enclosing scope (the scope in which a new binding should be created cannot
be determined unambiguously).

Names listed in a :keyword:`nonlocal` statement must not collide with
pre-existing bindings in the local scope.
When the definition of a function or class is nested (enclosed) within
the definitions of other functions, its nonlocal scopes are the local
scopes of the enclosing functions. The :keyword:`nonlocal` statement
causes the listed identifiers to refer to names previously bound in
nonlocal scopes. It allows encapsulated code to rebind such nonlocal
identifiers. If a name is bound in more than one nonlocal scope, the
nearest binding is used. If a name is not bound in any nonlocal scope,
or if there is no nonlocal scope, a :exc:`SyntaxError` is raised.

The nonlocal statement applies to the entire scope of a function or
class body. A :exc:`SyntaxError` is raised if a variable is used or
assigned to prior to its nonlocal declaration in the scope.

.. seealso::

:pep:`3104` - Access to Names in Outer Scopes
The specification for the :keyword:`nonlocal` statement.

**Programmer's note:** :keyword:`nonlocal` is a directive to the parser
and applies only to code parsed along with it. See the note for the
:keyword:`global` statement.


.. _type:

The :keyword:`!type` statement
Expand Down
Loading