View Source Witchcraft.Setoid (Witchcraft v1.0.6-doma)

A setoid is a type with an equivalence relation.

This is most useful when equivalence of some data is not the same as equality.

Since some types have differing concepts of equality, this allows overriding the behaviour from Kernel.==/2. To get the Setoid == operator override, simply use Witchcraft.Setoid.

type-class

Type Class

An instance of Witchcraft.Setoid must define Witchcraft.Setoid.equivalent?/2

Setoid [equivalent?/2]

Link to this section Summary

Functions

Compare two setoids and determine if they are equivalent.

Link to this section Types

Link to this section Functions

See Witchcraft.Setoid.nonequivalent?/2.

See Witchcraft.Setoid.equivalent?/2.

@spec equivalent?(t(), t()) :: boolean()

Compare two setoids and determine if they are equivalent.

Aliased as ==.

examples

Examples

iex> equivalent?(1, 2)
false

iex> import Kernel, except: [==: 2, !=: 2]
...> %{a: 1} == %{a: 1, b: 2}
false

equivalent?(%Maybe.Just{just: 42}, %Maybe.Nothing{})
#=> false

equivalence-not-equality

Equivalence not equality

baby_harry = %Wizard{name: "Harry Potter", age: 10}
old_harry  = %Wizard{name: "Harry Potter", age: 17}

def chosen_one?(some_wizard), do: equivalent?(baby_harry, some_wizard)

chosen_one?(old_harry)
#=> true
@spec nonequivalent?(t(), t()) :: boolean()

The opposite of equivalent?/2.

examples

Examples

iex> nonequivalent?(1, 2)
true