Arrow: Add remaining Monoid and Semigroup instances

[pakoito]

At the moment several instances from Scala are not available in Arrow, like the one for Try. The task is to do a pass on the codebase and write them.

[bassjacob]

I'd be happy to help with this

[pakoito]

Neat, we got Try and Either now :D

What's left?

[bassjacob]

Still to come:

• [x] function0/ function1 -https://github.com/scalaz/scalaz/blob/series/7.3.x/core/src/main/scala/scalaz/std/Function.scala
• [ ] char silly me there are no monoid or semigroup instances for char that I can think of
• [x] id
• [ ] boolean
• [x] const which can reuse some functions from the typeclasses file
• [ ] eval - I'm not sure what the semantics to choose for eval would be

I'll get started on id next

[bassjacob]

@pakoito Do you want arrow-data-instances as part of this issue or a separate one?

[pakoito]

Do you want arrow-data-instances as part of this issue or a separate one?

I'm not sure I follow.

[pakoito]

I'm not sure what the semantics to choose for eval would be

Let's do a live session when you reach it, I have an idea but would need to be in front of the code.

[bassjacob]

The data types I listed above are from arrow-instances-core. There's also a few missing I think from arrow-instances-data that we might want to add?

[pakoito]

Oh, yes, everything on the same ticket.