lkuczera / scalatypeclasses

Scala type classes workshop

scalatypeclasses

Scala type classes workshop

License

See the LICENSE file.

Exercise 1: Comparable

1. Define the ComparatorInt instance.
2. Define the min method, which should calculate the smallest collection element.
3. Define the max method, which should calculate the greatest collection element.
4. Define the ComparatorString instance.
5. Define the ComparatorAbsInt instance (which compares absolute values).
6. Define the ComparatorStringIgnoreCase instance (which ignores the distinction between uppercase and lowercase characters).
7. Add the + method to the Tree class.
8. Add the contains method to the Tree class.

Exercise 2: Monoid

1. Define the MonoidString instance.
2. Define the msum method, which has the following signature: def msum[T](list: T*)(implicit m: Monoid[T]): T
3. Define the MonoidSum instance.
4. Define the MonoidProduct instance.
5. Define the MonoidAnything instancee.
6. Define the MonoidAll instance.
7. Define the MonoidList instance.
8. Define the MonoidTuple2 instance.
9. Define the MonoidMap instance.

Exercise 3: Functor

1. Define the FunctorOption instance.
2. Define the FunctorList instance.
3. Define the FunctorTree instance.

Exercise 4: Foldable

1. Define the FoldableList instance.
2. Define the FoldableTree instance.
3. Define the fold method, which has the following signature: def fold[A:Monoid,F[A]:Foldable](f: F[A]): A
4. Define the toList method converting a foldable into a list.
5. Define the size method calculating the foldable size.

Exercise 5: Applic

1. Define the ApplicId instance.
2. Define the ApplicOption instance.
3. Implement the map method.
4. Define the lift2 method, which has the following signature: def lift2[F[_],A,B,C](a: F[A], b: F[B])(g: (A,B) => C)(implicit applic: Applic[F]): F[C]
5. Define the lift3 method, which has the following signature: def lift3[F[_],A,B,C,D](a: F[A], b: F[B], c: F[C])(g: (A,B,C) => D)(implicit applic: Applic[F]): F[D]
6. Define the ApplicList instance.
7. Define the ApplicZipList instance.

Exercise 6: Monad

1. Define the MonadOption instance.
2. Implement the map method.
3. Implement the ap method.
4. Define the foldM method, which has the following signature: def foldM[M[_],A,B](list: List[A])(v: B)(g: (B,A) => M[B])(implicit m: Monad[M]): M[B]
5. Define the MonadList instance.
6. Define the join method, which has the following signature: def join[M[_],A,B](mm: M[M[A]])(implicit m: Monad[M]): M[A]

Exercise 7: Travers

1. Define the TraversId instance.
2. Implement the map method.
3. Define the TraversOption instance.
4. Define the sequence method, which has the following signature: def sequence[T[_]:Travers,F[_]:Applic,A](t: T[F[A]]): F[T[A]]
5. Define the TraversList instance.
6. Implement the foldMap method.