Laws for Show and Read?

[David Feuer]

Double and Float instances are terminally broken in general. What's new?

On Wed, Jun 5, 2019, 2:56 PM Sven Panne <svenpanne at gmail.com> wrote:

> Am Mi., 5. Juni 2019 um 17:02 Uhr schrieb David Feuer <
> david.feuer at gmail.com>:
>
>> We already have the law
>>
>>   read . show = id
>>
>> which implies the injectivity and surjectivity conditions you specify.
>>
>
> I think this doesn't hold for the standard Read/Show instances for
> Double/Float: IEEE-754 NaNs have a sign bit and a payload, and  both parts
> are probably lost by the "read . show"-combination. The 2 infinities are
> probably OK, but what about -0 vs. +0?
>
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