Proposal to deprecate and then drop fromJust

Erik de Castro Lopo mle+hs at
Tue Feb 24 10:23:05 UTC 2015

Joachim Breitner wrote:

> -1
> If it wasn’t there, I probably would not vote for adding it, but in the
> interest of general stability, I believe removing this function is not
> worth the effort.

I think its interesting (I've heard this from a couple of people) that 
if this function was up for *addition* it would be rejected, but they do
not support its removal or even deprecation.

> Also, just removing fromMaybe when there are many other partial

Not fromMaybe (which is total), fromJust (which is partial) :-).

> functions, some in the Prelude, does not really cut it. If there was a
> larger proposal „Make Haskell free of Partial Functions“, then that
> would be a different thing.

Maybe this is a like strictness; Haskell users don't want a strict
version of Haskell so much as a Haskell where they have better control
over the the tradeoffs between lazy and strict evaluation.

Possibly what we need is a pragma to mark functions partial and a warning
flag that warns on usage of functions that have been marked partial.

Erik de Castro Lopo

More information about the Libraries mailing list