BoundedZeroSemilattice

Return the absorbing element for this zero semigroup.

Given Eq[A], return a PartialOrder[A] using the combine operator to determine the partial ordering. This method assumes combine functions as join (that is, as an upper bound).

This method returns:

0.0 if x = y -1.0 if y = combine(x, y) 1.0 if x = combine(x, y) NaN otherwise

Given Eq[A], return a PartialOrder[A] using the combine operator to determine the partial ordering. This method assumes combine functions as meet (that is, as a lower bound).

This method returns:

0.0 if x = y -1.0 if x = combine(x, y) 1.0 if y = combine(x, y) NaN otherwise

Associative operation which combines two values.

Example:

scala> import cats.kernel.instances.string._
scala> import cats.kernel.instances.int._
scala> import cats.kernel.instances.option._

scala> Semigroup[String].combine("Hello ", "World!")
res0: String = Hello World!

scala> Semigroup[Option[Int]].combine(None, Some(1))
res1: Option[Int] = Some(1)

Given a sequence of as, sum them using the monoid and return the total.

Example:

scala> import cats.kernel.instances.string._

scala> Monoid[String].combineAll(List("One ", "Two ", "Three"))
res0: String = One Two Three

scala> Monoid[String].combineAll(List.empty)
res1: String = ""

Return the identity element for this monoid.

Example:

scala> import cats.kernel.instances.int._
scala> import cats.kernel.instances.string._

scala> Monoid[String].empty
res0: String = ""

scala> Monoid[Int].empty
res1: Int = 0

Tests if a is the absorbing element.

Tests if a is the identity.

Example:

scala> import cats.kernel.instances.string._

scala> Monoid[String].isEmpty("")
res0: Boolean = true

scala> Monoid[String].isEmpty("something")
res1: Boolean = false