[Haskell-cafe] What to call Occult Effects

[Michal J Gajda]

Dear Kim,

This was not intended as caricature at all. But it seems an excellent
example of x-y problem indeed.
When asking for a real life examples, I provided a case when I can
provide example that is familiar to most readers:

T = Types
i = infer :: object -> type
c = check :: type -> object -> Bool

Laws just make sure that type checking is preserved over unification
or anti-unification (<>),
except for commutativity - which is omitted on purpose (further
description here: https://arxiv.org/abs/2011.03076.)

Naturally this example just enumerates the laws that are true for both
unification and anti-unification problems.

Your question would be however fitting for ICFP 2021 trivia, since
without examples provided by other haskell-cafe readers
I would not have guessed that you want to mean "occlusion", instead of
magic of "occult" here.

On Thu, Nov 12, 2020 at 2:33 AM Kim-Ee Yeoh <ky3 at atamo.com> wrote:
>
> (I'll respond with the original subject heading and with the full thread of Michal's reply copied below so that the convo stays in one place.)
>
> Hi Michal, I'm afraid you caricaturize my original email out of proportion here:
>
> > class Monoid m => T m o where
> > i :: o -> t
> > c :: t -> o -> Bool
> <snip>
(...)
> On Wed, Nov 11, 2020 at 8:36 PM Michal J Gajda <mgajda at mimuw.edu.pl> wrote:
(...)
>> Such that the following laws are satisfied:
>>
>> Forall x y z m n.
>> c (i x) x =True
>> c mempty x = False
>> c m y = True => c (m <> n) y = True
>> c n y = True => c (m <> n) y = True
>>
>> What does it tell you about the definitions?
>> Can you tell if this set of laws is correctly stated or exhaustive?
>> Whether it models what I intend to do?
>> Without further examples could I claim that it may be universal model for some phenomena f and g?
-- 
  Cheers
    Michał