I like this avenue of thought! I would suggest the following:
Step 1: Accept this proposal.
Step 2: Introduce more *educational* error messages in the exceptions.
Instead of "error: empty list", for example, it could be "error: unguarded
use of head has failed".
Sorry for phone-brevity.
On Mon, 31 May 2021, 19.31 Hécate,
I think the vast majority of the functions presented in this proposal have a total counterpart, whether it is a function or a code pattern. We have NonEmpty in `base`, as well as ExceptT/MonadError and Exceptions to allow us to mimic such a cul-de-sac in the code with appropriate annotations around it.
Le 31/05/2021 à 18:15, Henning Thielemann a écrit :
On Mon, 31 May 2021, Ryan Trinkle via Libraries wrote:
I certainly agree that a more systemic solution would be preferable. However, none have been forthcoming in the 15 or so years I've been using Haskell. The use of partial functions in library code has been one of the few consistent sources of multi-day debugging exercises in Haskell that I've seen, and even cutting that down in an ad-hoc way would be valuable, since there are probably a dozen functions that account for 80% of the debugging hours (I'd certainly like to see fromJust on that list, for example).
I understand the proposal as tagging all partial functions in a compiler accessible way, in order to tell the user: Don't use that function!
If so, then we should make sure that every such tagged function has a total counterpart.
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