[Haskell-cafe] How to create a list of each constructor value

[Joachim Breitner]

Hi,

Am Mittwoch, dem 30.11.2022 um 16:21 +0100 schrieb Henning Thielemann:
> > I want to create a list of each values in order to create meaningfull 
> > error message for the user and simplify my Arbitrary instances.
> 
> deriving (Enum, Bounded)
> 
> then use [minBound .. maxBound]

if you want to golf it a bit more, then

   [minBound..]
   
works as well.

(I vaguely remember that there was a variant that didn’t even need
Bounded, just, but I don’t recall it right now. Maybe it was
[toEnum 0..]? but that only works for certain instances.)

Cheers,
Joachim




-- 
Joachim Breitner
  mail at joachim-breitner.de
  http://www.joachim-breitner.de/