Deprecating fromIntegral

Jon Fairbairn jon.fairbairn at
Thu Sep 28 08:38:03 UTC 2017

Niklas Hambüchen <mail at> writes:

>> I'm -1 on deprecating it, and +1 on adding additional conversion
>> functions of various sorts: explicit widening, explicit narrowing, etc.
> What is your reasoning against deprecating it?

May I just interject that fromIntegral itself is not the
problem. There’s nothing wrong with “fromIntegral 5::Ratio
Integer” for example. The problem is having the type “(Num b,
Integral a) => a->b”, which drags in all the horror that is Num.

A type more like “(Integral a, InfinitePrecisionNumber b) => a
-> b” (and an appropriate definition of the class) would allow
its continued use in places where it’s safe.

Jón Fairbairn                                 Jon.Fairbairn at

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