[Python-Dev] PEP 515: Underscores in Numeric Literals

[Chris Angelico]

On Thu, Feb 11, 2016 at 7:22 PM, Georg Brandl <g.brandl at gmx.net> wrote:
> * Allowing underscores in string arguments to the ``Decimal`` constructor.  It
>   could be argued that these are akin to literals, since there is no Decimal
>   literal available (yet).
>
> * Allowing underscores in string arguments to ``int()`` with base argument 0,
>   ``float()`` and ``complex()``.

I'm -0.5 on both of these, with the caveat that if either gets done,
both should be. Decimal() shouldn't be different from int() just
because there's currently no way to express a Decimal literal; if
Python 3.7 introduces such a literal, there'd be this weird rule
difference that has to be maintained for backward compatibility, and
has no justification left.

(As a side point, I would be fully in favour of Decimal literals. I'd
also be in favour of something like "from __future__ import
fraction_literals" so 1/2 would evaluate to Fraction(1,2) rather than
0.5. Hence I'm inclined *not* to support underscores in Decimal().)

ChrisA