[Python-ideas] Decimal literal?

Jim Jewett jimjjewett at gmail.com
Fri Dec 5 19:53:33 CET 2008

On Thu, Dec 4, 2008 at 4:45 AM, Cesare Di Mauro
<cesare.dimauro at a-tono.com> wrote:
> But at least it will be more usable to have a
> short-hand for decimal declaration:

In isolation, a decimal literal sounds nice.

But it may not be used often enough to justify the extra mental complexity.

What should the following mean?

>>> a = 123X

It isn't obvious, which means that either it gets used all the time
(decimal won't) or people will have to look it up -- or just guess,
and sometimes get it wrong.

> a = 1234.567d

To someone who hasn't programmed much with decimal floating point,
what does the "d" mean?

Could it indicate "use double-precision"?

Could it just mean that the written representation is "decimal" as
opposed to "octal" or "hexadecimal", but that the internal form is
still binary?

> a = 1234.567d

> is simpler than:

[reworded to be even shorter per use]

>>> from decimal import Decimal as d
>>> a = d('1234.5678')

but if you really have enough Decimal literals for the difference to
matter, you could always write your own helper function.

>>> # pretend to be using the European decimal point
>>> a = d(1234,5678)

>>> # maps easily to the tuple-format constructor
>>> a = d(12345678, -4)

My own hunch is that until Decimal is used enough that people start
putting this sort of constructor into their personal libraries, it
probably doesn't need a literal.


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