Proposal to deprecate and then drop fromJust

Ivan Lazar Miljenovic ivan.miljenovic at
Tue Feb 24 10:43:31 UTC 2015

On 24 February 2015 at 21:14, Henning Thielemann
<lemming at> wrote:
> On Tue, 24 Feb 2015, Ivan Lazar Miljenovic wrote:
>> I've used fromJust in the past when I knew the value would be Just by
>> construction.
> If you know that the value is always Just by construction, why don't you
> express this with the types, i.e. by turning from 'Maybe a' to 'a'? When
> asking this question myself I could remove fromJusts in most cases. The
> problem is most oftenly that you drop the information that a value is Just
> too early and then you cannot recover it later.

Because the function that returns a Just value is from another library
or function which for safety's sake should return a Just, but in this
case I know that it won't?

Ivan Lazar Miljenovic
Ivan.Miljenovic at

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