Band instances must satisfy scalaz.Semigroup.SemigroupLaw and 1 additional law:
A semigroup in type F must satisfy two laws:
The binary operation to combine f1
and f2
.
The binary operation to combine f1
and f2
.
Implementations should not evaluate the by-name parameter f2
if result
can be determined by f1
.
An scalaz.Apply, that implements ap
with append
.
An scalaz.Apply, that implements ap
with append
. Note
that the type parameter α
in Apply[λ[α => F]]
is
discarded; it is a phantom type. As such, the functor cannot
support scalaz.Bind.
Every Semigroup
gives rise to a scalaz.Compose, for which
the type parameters are phantoms.
Every Semigroup
gives rise to a scalaz.Compose, for which
the type parameters are phantoms.
compose.semigroup
= this
The default definition exploits idempotency to optimise to O(1)
scalaz.Semigroup which is also idempotent, i.e. appending a value with itself results in the same value.
scalaz.Band.BandLaw