Prepare for 2.0 release

[garyb]

Resolves #37, resolves #41

[garyb]

Figured I may as well add the general ForeignError from #37 - it seems harmless enough.

[paf31]

Looks good, but let's discuss the use of NonEmpty. I think it would be nice to move NonEmpty to the top level, make it a Semigroup and give an Alt instance to F which combined errors using that Semigroup. What do you think?

[garyb]

I did start looking at that, but it wasn't really obvious to me how you'd actually get more than one failure out of the "parsing" anyway?

[paf31]

Using <|>?

[paf31]

i.e. using the Except (NonEmpty ForeignError) monad in place of Either.

[garyb]

Ok, sounds good to me. I take it we don't need the list in TypeError then? (although it will give slightly less good error messages)

[paf31]

I think we could get rid of that, since that's more of an error message rendering problem, right?

[garyb]

Yeah, exactly

[paf31]

It might be worth extracting Left <<< NE.singleton <<< TypeMismatch into a function here.

[paf31]

Can this use Except so that we get the right Alt instance?

[garyb]

Ah right, I was trying to avoid adding the -transformers dependency, but yep, good point.

[paf31]

👍 Thanks for this.

[garyb]

Maybe the MultipleErrors I just added here would be something worth adding in transformers?

[paf31]

Could we add it in nonempty? We have non-empty containers, but we could also have non-empty base types with Monoid a => Semigroup (NonEmpty a).

[garyb]

Something like newtype NonEmptySemigroup s a = Semigroup s => NonEmptySemigroup (NonEmpty f a)? (but not with the constraint there obviously), or like newtype NonEmptyList = NonEmptyList (NonEmpty List)? We can't do the latter due to the dependency order, but something like the former would work.

[paf31]

Never mind, I'm not sure what I was thinking. I think having a newtype around NonEmpty List somewhere would be good, although I'm fine with leaving this here too.

[garyb]

Yeah, it's fine here, just it seems like something that I'll want to use commonly with Except / MonadError in cases that have nothing to do with Foreign.

[garyb]

I could just make a new library for it I guess.

[paf31]

Could it go into lists?

[garyb]

Yeah, I'll do that.

[paf31]

What about leaving the type here for now, hiding its constructor and adding non-empty lists into lists later?

[garyb]

Done at last I think!

[paf31]

👍 Thanks, looks great!