bpo-26701: Improve documentation for the rounding special methods. (#6054)
diff --git a/Doc/reference/datamodel.rst b/Doc/reference/datamodel.rst
index 26ad7b8..1e93ef4 100644
--- a/Doc/reference/datamodel.rst
+++ b/Doc/reference/datamodel.rst
@@ -2364,28 +2364,17 @@
.. method:: object.__complex__(self)
object.__int__(self)
object.__float__(self)
- object.__round__(self, [,n])
.. index::
builtin: complex
builtin: int
builtin: float
- builtin: round
Called to implement the built-in functions :func:`complex`,
- :func:`int`, :func:`float` and :func:`round`. Should return a value
+ :func:`int` and :func:`float`. Should return a value
of the appropriate type.
-.. method:: object.__trunc__(self)
-
- Called to implement :meth:`math.trunc`. Should return the value of the
- object truncated to a :class:`numbers.Integral` (typically an
- :class:`int`). If a class defines :meth:`__trunc__` but not
- :meth:`__int__`, then :meth:`__trunc__` is called to implement the
- built-in function :func:`int`.
-
-
.. method:: object.__index__(self)
Called to implement :func:`operator.index`, and whenever Python needs to
@@ -2401,6 +2390,23 @@
the same value.
+.. method:: object.__round__(self, [,ndigits])
+ object.__trunc__(self)
+ object.__floor__(self)
+ object.__ceil__(self)
+
+ .. index:: builtin: round
+
+ Called to implement the built-in function :func:`round` and :mod:`math`
+ functions :func:`~math.trunc`, :func:`~math.floor` and :func:`~math.ceil`.
+ Unless *ndigits* is passed to :meth:`!__round__` all these methods should
+ return the value of the object truncated to an :class:`~numbers.Integral`
+ (typically an :class:`int`).
+
+ If :meth:`__int__` is not defined then the built-in function :func:`int`
+ falls back to :meth:`__trunc__`.
+
+
.. _context-managers:
With Statement Context Managers