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FloatInstances.scala
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FloatInstances.scala
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/*
* Copyright (c) 2015 Typelevel
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
package cats.kernel
package instances
trait FloatInstances {
implicit val catsKernelStdOrderForFloat: Order[Float] with Hash[Float] = new FloatOrder
implicit val catsKernelStdGroupForFloat: CommutativeGroup[Float] = new FloatGroup
}
/**
* This is only approximately associative.
*/
class FloatGroup extends CommutativeGroup[Float] {
def combine(x: Float, y: Float): Float = x + y
def empty: Float = 0f
def inverse(x: Float): Float = -x
override def remove(x: Float, y: Float): Float = x - y
}
/**
* Due to the way floating-point equality works, this instance is not
* lawful under equality, but is correct when taken as an
* approximation of an exact value.
*
* If you would prefer an absolutely lawful fractional value, you'll
* need to investigate rational numbers or more exotic types.
*/
class FloatOrder extends Order[Float] with Hash[Float] {
def hash(x: Float): Int = x.hashCode()
def compare(x: Float, y: Float): Int =
java.lang.Float.compare(x, y)
override def eqv(x: Float, y: Float): Boolean = x == y
override def neqv(x: Float, y: Float): Boolean = x != y
override def gt(x: Float, y: Float): Boolean = x > y
override def gteqv(x: Float, y: Float): Boolean = x >= y
override def lt(x: Float, y: Float): Boolean = x < y
override def lteqv(x: Float, y: Float): Boolean = x <= y
override def min(x: Float, y: Float): Float =
java.lang.Math.min(x, y)
override def max(x: Float, y: Float): Float =
java.lang.Math.max(x, y)
}