diff --git a/Doc/library/typing.rst b/Doc/library/typing.rst index 8b464be14b059e..54a19ae0b6bebc 100644 --- a/Doc/library/typing.rst +++ b/Doc/library/typing.rst @@ -1609,11 +1609,11 @@ without the dedicated syntax, as documented below. class Sequence[T]: # T is a TypeVar ... - This syntax can also be used to create bound and constrained type + This syntax can also be used to create bounded and constrained type variables:: - class StrSequence[S: str]: # S is a TypeVar bound to str - ... + class StrSequence[S: str]: # S is a TypeVar with a `str` upper bound; + ... # we can say that S is "bounded by `str`" class StrOrBytesSequence[A: (str, bytes)]: # A is a TypeVar constrained to str or bytes @@ -1646,8 +1646,8 @@ without the dedicated syntax, as documented below. """Add two strings or bytes objects together.""" return x + y - Note that type variables can be *bound*, *constrained*, or neither, but - cannot be both bound *and* constrained. + Note that type variables can be *bounded*, *constrained*, or neither, but + cannot be both bounded *and* constrained. The variance of type variables is inferred by type checkers when they are created through the :ref:`type parameter syntax ` or when @@ -1657,8 +1657,8 @@ without the dedicated syntax, as documented below. By default, manually created type variables are invariant. See :pep:`484` and :pep:`695` for more details. - Bound type variables and constrained type variables have different - semantics in several important ways. Using a *bound* type variable means + Bounded type variables and constrained type variables have different + semantics in several important ways. Using a *bounded* type variable means that the ``TypeVar`` will be solved using the most specific type possible:: x = print_capitalized('a string') @@ -1672,8 +1672,8 @@ without the dedicated syntax, as documented below. z = print_capitalized(45) # error: int is not a subtype of str - Type variables can be bound to concrete types, abstract types (ABCs or - protocols), and even unions of types:: + The upper bound of a type variable can be a concrete type, abstract type + (ABC or Protocol), or even a union of types:: # Can be anything with an __abs__ method def print_abs[T: SupportsAbs](arg: T) -> None: @@ -1717,7 +1717,7 @@ without the dedicated syntax, as documented below. .. attribute:: __bound__ - The bound of the type variable, if any. + The upper bound of the type variable, if any. .. versionchanged:: 3.12 @@ -1903,7 +1903,7 @@ without the dedicated syntax, as documented below. return x + y Without ``ParamSpec``, the simplest way to annotate this previously was to - use a :class:`TypeVar` with bound ``Callable[..., Any]``. However this + use a :class:`TypeVar` with upper bound ``Callable[..., Any]``. However this causes two problems: 1. The type checker can't type check the ``inner`` function because