gh-121798: Add class method Decimal.from_number() (GH-121801)

It is an alternate constructor which only accepts a single numeric argument.
Unlike to Decimal.from_float() it accepts also Decimal.
Unlike to the standard constructor, it does not accept strings and tuples.

1 files changed, 17 insertions, 0 deletions

diff --git a/Doc/library/decimal.rst b/Doc/library/decimal.rst
index 916f17c..c9a3e44 100644
--- a/Doc/library/decimal.rst
+++ b/Doc/library/decimal.rst
@@ -598,6 +598,23 @@ Decimal objects
 
       .. versionadded:: 3.1
 
+   .. classmethod:: from_number(number)
+
+      Alternative constructor that only accepts instances of
+      :class:`float`, :class:`int` or :class:`Decimal`, but not strings
+      or tuples.
+
+      .. doctest::
+
+          >>> Decimal.from_number(314)
+          Decimal('314')
+          >>> Decimal.from_number(0.1)
+          Decimal('0.1000000000000000055511151231257827021181583404541015625')
+          >>> Decimal.from_number(Decimal('3.14'))
+          Decimal('3.14')
+
+      .. versionadded:: 3.14
+
    .. method:: fma(other, third, context=None)
 
       Fused multiply-add.  Return self*other+third with no rounding of the