Reimplement Maybe monad wihtout RightBiased and LeftBiased

[moba1]

• reimplement these methods:

  • #or(a): if self is Just, return self. but self is Nothing, return Just.new(a)
    • ex Monads::Maybe.return(1).or(Monads::Maybe.return(2)) == Monads::Maybe.return(1)
  • #value_or(a): if self is Just, return Just#value!. self is Nothing, return a
    • ex: Monads::Maybe.return(1).value_or(4) == 1

• add following method:

  • #map_or(a, &block): if self is Just, return Just#value! applied &block. self is Nothing, return a
    • ex: Monads::Maybe.return(3).map_or(1) {|x| x + 1} == 4

• add Monad(T) and Functor(T) and Module. Maybe implements these modules.

• replace these methods:

  • #fmap
    • ex: Monads::Maybe.return(1).fmap {|x| x * 2} == Monads::Maybe.return(2)
  • #bind
    • ex: Monads::Maybe.return(1).bind {|x| Monads::Maybe.return(x.to_s)} == Monads::Maybe.return("1")

[alex-lairan]

Crystal and Haskell are very differents.

They don't have the same naming convention and not the same logic.

Haskell doesn't have inheritance (composition is key 😆) and he optimise his code in a different way than Crystal.

I think also that ulgy name (in crystal) will not help people to get in monads.

[moba1]

I pushed wrong author, hence, I repushed.

[moba1]

Removed wrong commiter from history

[moba1]

Organize commit

[moba1]

@alex-lairan All the pointed out parts have been fixed.
please check.

[alex-lairan]

I prefer this naming :)

2/3 thing's to change and LGTM

[moba1]

Do you have anything else you want to point out?

[alex-lairan]

I don't think so.

I will implement a CI to simplify the review process.

[moba1]

For now, should I merge?

[alex-lairan]

Yes, let's go