From 48ddbb2b7a0fe01ad85acdeb2841e7ec9cd41bcd Mon Sep 17 00:00:00 2001 From: hauntsaninja Date: Mon, 10 Oct 2022 00:12:58 -0700 Subject: [PATCH] gh-96130: Rephrase use of "typecheck" verb for clarity I'm sympathetic to the issue report, especially in case this helps clarify to new users that Python itself does not do type checking at runtime --- Doc/library/typing.rst | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/Doc/library/typing.rst b/Doc/library/typing.rst index f63d61eb1ea38d..fee55becc7f57d 100644 --- a/Doc/library/typing.rst +++ b/Doc/library/typing.rst @@ -105,7 +105,7 @@ A type alias is defined by assigning the type to the alias. In this example, def scale(scalar: float, vector: Vector) -> Vector: return [scalar * num for num in vector] - # typechecks; a list of floats qualifies as a Vector. + # passes type checking; a list of floats qualifies as a Vector. new_vector = scale(2.0, [1.0, -4.2, 5.4]) Type aliases are useful for simplifying complex type signatures. For example:: @@ -147,10 +147,10 @@ of the original type. This is useful in helping catch logical errors:: def get_user_name(user_id: UserId) -> str: ... - # typechecks + # passes type checking user_a = get_user_name(UserId(42351)) - # does not typecheck; an int is not a UserId + # fails type checking; an int is not a UserId user_b = get_user_name(-1) You may still perform all ``int`` operations on a variable of type ``UserId``, @@ -176,7 +176,7 @@ It is invalid to create a subtype of ``Derived``:: UserId = NewType('UserId', int) - # Fails at runtime and does not typecheck + # Fails at runtime and does not pass type checking class AdminUserId(UserId): pass However, it is possible to create a :class:`NewType` based on a 'derived' ``NewType``:: @@ -463,12 +463,12 @@ value of type :data:`Any` and assign it to any variable:: s = a # OK def foo(item: Any) -> int: - # Typechecks; 'item' could be any type, + # Passes type checking; 'item' could be any type, # and that type might have a 'bar' method item.bar() ... -Notice that no typechecking is performed when assigning a value of type +Notice that no type checking is performed when assigning a value of type :data:`Any` to a more precise type. For example, the static type checker did not report an error when assigning ``a`` to ``s`` even though ``s`` was declared to be of type :class:`str` and receives an :class:`int` value at @@ -500,20 +500,20 @@ reject almost all operations on it, and assigning it to a variable (or using it as a return value) of a more specialized type is a type error. For example:: def hash_a(item: object) -> int: - # Fails; an object does not have a 'magic' method. + # Fails type checking; an object does not have a 'magic' method. item.magic() ... def hash_b(item: Any) -> int: - # Typechecks + # Passes type checking item.magic() ... - # Typechecks, since ints and strs are subclasses of object + # Passes type checking, since ints and strs are subclasses of object hash_a(42) hash_a("foo") - # Typechecks, since Any is compatible with all types + # Passes type checking, since Any is compatible with all types hash_b(42) hash_b("foo")