Author serhiy.storchaka
Recipients John.Yeung, facundobatista, mark.dickinson, rhettinger, serhiy.storchaka, skrah, terry.reedy
Date 2018-03-15.23:00:55
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Message-id <1521154855.8.0.467229070634.issue33083@psf.upfronthosting.co.za>
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Many functions implemented in C accept Decimal instances.

>>> chr(decimal.Decimal(65.2))
'A'

This is because PyLong_AsLong() and similar functions call __int__().

Floats are specially prohibited when convert arguments with PyArg_Parse() with the "i" format unit.

>>> chr(65.2)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: integer argument expected, got float

The specific of factorial() is that it accepts integral floats and raises ValueError instead of TypeError for non-integral floats. Maybe it was planned to extend factorial() to non-integral floats by using a gamma function. All other functions in the math module worked with floats at the time of adding factorial() in issue2138. math.gamma() was added 1.5 years later in issue3366.
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Date User Action Args
2018-03-15 23:00:55serhiy.storchakasetrecipients: + serhiy.storchaka, rhettinger, terry.reedy, facundobatista, mark.dickinson, skrah, John.Yeung
2018-03-15 23:00:55serhiy.storchakasetmessageid: <1521154855.8.0.467229070634.issue33083@psf.upfronthosting.co.za>
2018-03-15 23:00:55serhiy.storchakalinkissue33083 messages
2018-03-15 23:00:55serhiy.storchakacreate