Add Data.Sequence.toList

[brandonchinn178]

Re-opening a thread for #744. I'm happy to email the libraries list for this

[chessai]

The libraries mailing list is archaic and mostly used now to request package takeovers or for CLC elections. Back in 2020 it was still used a lot more. I don't think posting there is necessary anymore.

[meooow25]

Is the motivation same as #744 (comment)?

I don't disagree with the points, but

• An alias introduces an unnecessary choice for the user
• The same motivations apply to all typeclass methods, how do we decide if a method deserves a monomorphic alias?

[brandonchinn178]

My major motivation here is consistency. Data.Set.toList is the same as Foldable.toList, thus Data.Sequence should match the same API.

[RossPaterson]

From the mailing list:

I do see that Map.toList /= Foldable.toList. But Set.toList == Foldable.toList, and it's not obvious to me why Set should have toList and not Seq.

I think the reason for the inconsistency is that Data.Map.toList and Data.Set.toList predate Foldable and Data.Sequence. Being half-consistent with this accident doesn't seem to be a compelling reason for this change. The change would also introduce an extra name clash (for the same underlying function) that would need tweaked imports, including in code that compiles now.

[brandonchinn178]

Ah thanks for the context, that makes sense. But I would still argue it's worthwhile to do, unless there's a plan to remove Data.Set.toList.

The same motivations apply to all typeclass methods, how do we decide if a method deserves a monomorphic alias?

IMO conversion functions like toList/fromList should be exceptional, since it's an API boundary between two types, where type ambiguity is most likely to appear. I'd also argue that Seq.toList == Foldable.toList is an implementation detail, and the two have different semantic meanings.