What does the NonEmpty String list contain in namesFromLabelsWith?

[sir4ur0n]

Function namesFromLabelsWith takes as argument a function that receives a NonEmpty String, but the documentation does not explain what this list contains.
The documented example just takes the last value of that list to obtain the Haskell type.

I have fiddled with this function in a REPL but I always get back a list of exactly 1 element.

Can you explain (and ideally, add to the function documentation) what this list may contain, besides the last element always being the Haskell field name?

[shane-circuithub]

If you have a Rel8able like:

data Foo f = Foo
  { a :: Column f Bool
  , b :: Column f Char
  }
  deriving (Generic, Rel8able)

data Bar f = Bar
  { foo1 :: Foo f
  , foo2 :: Foo f
  }
  deriving (Generic, Rel8able)

Then the argument passed to namesFromLabelsWith will contain things like ["foo1", "a"], ["foo1", "b"], ["foo2", "a"], ["foo2", "b"].

[sir4ur0n]

Thank you for the answer 🙏

Shouldn't this be explained in the Haddock documentation? I think it trips up many developers while getting acquainted with Rel8 😅 (Everyone in my team of Haskell developers wondered the same)

[ocharles]

Yea, it definitely should be. @sir4ur0n do you think you'd be able to contribute a little sentence doc PR? If not, I'll try and get to it soon.

[sir4ur0n]

I'm usually ok with contributing documentation to libraries, but I don't feel comfortable enough to do this one, because I don't fully understand the example above given by @shane-circuithub (#279 (comment)) 😅

And to the best of my knowledge, the pattern of nesting Column fields in a sub-type of a Rel8able type is not showcased in the documentation, so I feel like this would also deserve documentation.

I'd be happy to review any such PR and give feedback/suggestions though

[ocharles]

Ok, that's fair!