5 Jun
2019
5 Jun
'19
3:15 p.m.
Double and Float instances are terminally broken in general. What's new?
On Wed, Jun 5, 2019, 2:56 PM Sven Panne
Am Mi., 5. Juni 2019 um 17:02 Uhr schrieb David Feuer < david.feuer@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?