Funx.Monoid protocol (funx v0.8.4)

A protocol defining the Monoid algebraic structure, which consists of an identity element and an associative binary operation for combining values.

This protocol provides four key functions:

Summary

t()

All the types that implement this protocol.

Combines two monoid structs.

Returns the identity element for the given monoid struct.

Extracts the underlying value from the monoid struct.

Wraps a value into the given monoid struct.

@type t() :: term()

All the types that implement this protocol.

@spec append(t(), t()) :: t()

Combines two monoid structs.

The operation must satisfy associativity:

append(append(a, b), c) == append(a, append(b, c))

iex> Funx.Monoid.append(%Funx.Monoid.Sum{value: 1}, %Funx.Monoid.Sum{value: 2})
%Funx.Monoid.Sum{value: 3}

@spec empty(t()) :: t()

Returns the identity element for the given monoid struct.

The identity element is a special value that satisfies the property:

append(empty(monoid_struct), x) == x
append(x, empty(monoid_struct)) == x

iex> Funx.Monoid.empty(%Funx.Monoid.Sum{})
%Funx.Monoid.Sum{value: 0}

@spec unwrap(t()) :: any()

Extracts the underlying value from the monoid struct.

iex> Funx.Monoid.unwrap(%Funx.Monoid.Sum{value: 10})
10

@spec wrap(t(), any()) :: t()

Wraps a value into the given monoid struct.

iex> Funx.Monoid.wrap(%Funx.Monoid.Sum{}, 10)
%Funx.Monoid.Sum{value: 10}