Maybe as a Semigroup?

[i-am-tom]

Hello!

Firstly, this project is great, and I've been playing with it for a few weeks. I have to ask, though: is there a reason why Maybe doesn't have a concat method defined? As I see it, the concatenation would work like this:

Nothing `concat` Nothing = Nothing
Nothing `concat` x = x
x `concat` Nothing = x
(Just x) `concat` (Just y) = Just (x `concat` y)

I'm more than happy to submit the PR if this sounds reasonable - just thought I'd double check in case I'd missed something obvious :)

[davidchambers]

That's the way S.Maybe#concat is defined.

There's significant overlap between ramda-fantasy and Sanctuary. There's been talk of merging the two projects, in #105 and perhaps in other threads, to avoid further duplication of effort.

I imagine a pull request to define Maybe#concat would be accepted, particularly since what you're proposing is compatible with Sanctuary and would thus not be a source of conflict if and when we merge the projects. :)

[buzzdecafe]

what @davidchambers said. i'd be happy to see a pr on this.

[TheLudd]

Are the middle cases valid?

Nothing `concat` x = x
x `concat` Nothing = x

Should it not be like this?

Nothing `concat` (Just x) = (Just x)
(Just x) `concat` Nothing = (Just x)

[i-am-tom]

Would they not both achieve the same results? Either way, it was just a brief explanation :)

I should have a PR ready by the end of the day!

[TheLudd]

I am saying that Nothingconcatx = x violates the contract unless x is an instance of Maybe.

concat must return a value of the same Semigroup.

https://github.com/fantasyland/fantasy-land#semigroup

[i-am-tom]

Ah, beg your pardon. What I was writing was meant to look more like the instance implementation for a Maybe type in Haskell. Still, as long as the idea is otherwise sound, I'll press on :)

[i-am-tom]

Closing - PR's at #123 !