[Python-ideas] float('∞')=float('inf')

Joshua Landau joshua at landau.ws
Sun Jul 14 10:56:59 CEST 2013


On 14 July 2013 09:40, Serhiy Storchaka <storchaka at gmail.com> wrote:
> 13.07.13 00:55, Joshua Landau wrote:
>> On 12 July 2013 22:46, Serhiy Storchaka wrote:
>>> 13.07.13 00:27, Joshua Landau wrote:
>>>>
>>>> ½ === 1/2; thus is an expression
>>>
>>> 0.5 === 5/10. Isn't it an expression?
>>
>> No. That's like saying "1 === 2/2". There is a much more obvious
>> equivalence between two ways of writing "1/2" than between two ways of
>> displaying the result of "1/2".
>
> 0.5 is 5/10 by definition. The result of 1/2 is a fraction ½.

I don't understand. What are you trying to say?


>> Plus, why on earth would you use recurrence for floats? Give me a use
>> case. There's a good reason for float infinity.
>
> This is only a way to spell a general fraction in decimal. On other hand, ∞
> is even not a real number.

That's not a use-case.


>>>> The informal definition for "expression" with regards
>>>> to int and float I'm using is basically the measure of how much
>>>> more parsing code would need to be implemented.
>>>
>>> ½ requires no more parsing code then ∞.
>>
>> Au contraire, if you accept ½ you are bound by law to accept all of the
>> other fractions -- that's much more code than just allowing ∞.
>
> If you accept ∞ you are bound by law to accept ½ and all of the other
> fractions — and that's much more code than just allowing ∞.

I was afraid that people would go and take this too literally. But
either way, if you accept ½ and reject ¾, you have made a really bad
design decision. If you accept ∞ and reject ½, the atrocity of that
decision is much less. I would say it's a good choice, you may say it
is bad. But if you say those are equivalently bad decisions you're
simply wrong and there's not much more I can say.


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