Mark partial functions as such

[David Feuer]

Yes, I think so. What about functions like length? length (repeat ()) is
bottom. repeat () is not bottom. Ergo, length is partial. But I don't think
we want to say that!

On Thu, Aug 30, 2018, 10:05 PM Daniel Díaz Casanueva <dhelta.diaz at gmail.com>
wrote:

> +1 from me too. The partiality of a function seems to me like something
> that should be documented.
>
> Best,
> Daniel
>
> Am Fr., 31. Aug. 2018 um 02:10 Uhr schrieb Richard Eisenberg <
> rae at cs.brynmawr.edu>:
>
>> Proposal: Mark partial functions in `base` as partial
>>
>> Motivation: I'm about to teach Haskell to a classful of beginners. In my
>> experience, they will soon reach for functions like `head` and `tail`,
>> because pattern-matching is foreign to them. I would love just to be able
>> to say "Don't use partial functions", but many students will not easily be
>> able to tell partial functions from total ones.
>>
>> I do expect this problem to work itself out rather quickly, and then
>> students will be able to identify partial functions, but loudly marking
>> partial functions as partial seems like a small service to everyone and a
>> bigger one to newbies. I don't see any downsides.
>>
>> Thoughts?
>>
>> Thanks,
>> Richard
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