@spec compare(left(), right()) :: Comparable.ord()

Compare left and right term

Examples

iex> Comp.compare(1, 2)
:lt
iex> Comp.compare(2, 1)
:gt
iex> Comp.compare(1, 1)
:eq

Helper to define ordering relation for pair of types, accepts two term :: type pairs and block of code where relation is described.

Examples

iex> quote do
...>   use Comp
...>   defmodule Foo do
...>     defstruct [:value, :meta]
...>   end
...>   defmodule Bar do
...>     defstruct [:value, :meta]
...>   end
...>   defcomparable %Foo{value: left} :: Foo, %Foo{value: right} :: Foo do
...>     Comp.compare(left, right)
...>   end
...>   defcomparable %Foo{value: left} :: Foo, %Bar{value: right} :: Bar do
...>     Comp.compare(left, right)
...>   end
...>   defcomparable %Foo{value: left} :: Foo, right :: Integer do
...>     Comp.compare(left, right)
...>   end
...> end
...> |> Code.compile_quoted
iex> quote do
...>   x = %Foo{value: 1, meta: 1}
...>   y = %Foo{value: 1, meta: 2}
...>   Comp.equal?(x, y) && Comp.equal?(y, x)
...> end
...> |> Code.eval_quoted
...> |> elem(0)
true
iex> quote do
...>   x = %Foo{value: 1, meta: 1}
...>   y = %Bar{value: 1, meta: 2}
...>   Comp.equal?(x, y) && Comp.equal?(y, x)
...> end
...> |> Code.eval_quoted
...> |> elem(0)
true
iex> quote do
...>   x = %Foo{value: 1, meta: 1}
...>   y = 1
...>   Comp.equal?(x, y) && Comp.equal?(y, x)
...> end
...> |> Code.eval_quoted
...> |> elem(0)
true

@spec equal?(left(), right()) :: boolean()

Is left term equal to right term?

Examples

iex> Comp.equal?(1, 1)
true
iex> Comp.equal?(1, :hello)
false

@spec greater_or_equal?(left(), right()) :: boolean()

Is left term greater or equal to right term?

Examples

iex> Comp.greater_or_equal?(1, 1)
true
iex> Comp.greater_or_equal?(1, 2)
false
iex> Comp.greater_or_equal?(2, 1)
true

@spec greater_than?(left(), right()) :: boolean()

Is left term greater than right term?

Examples

iex> Comp.greater_than?(1, 1)
false
iex> Comp.greater_than?(1, 2)
false
iex> Comp.greater_than?(2, 1)
true

@spec less_or_equal?(left(), right()) :: boolean()

Is left term less or equal to right term?

Examples

iex> Comp.less_or_equal?(1, 1)
true
iex> Comp.less_or_equal?(1, 2)
true
iex> Comp.less_or_equal?(2, 1)
false

@spec less_than?(left(), right()) :: boolean()

Is left term less than right term?

Examples

iex> Comp.less_than?(1, 1)
false
iex> Comp.less_than?(1, 2)
true
iex> Comp.less_than?(2, 1)
false

@spec max(left(), right()) :: left() | right()

Returns the biggest of the two given terms, if terms are equal - then the first one is returned

Examples

iex> Comp.max(1, 1)
1
iex> Comp.max(1, 2)
2
iex> Comp.max(2, 1)
2

@spec memoize_dispatch(boolean()) :: :ok

Turns memoization of the type-pair dispatch on or off, and clears it.

Defaults to on in :embedded mode — a release, where every module is loaded at boot so a resolution cannot change — and off under mix, iex and tests, where code is loaded lazily and recompiled in place.

Turn it on to measure or test the cached path, and off (or call reset_dispatch/0) after defining a comparator at runtime.

@spec min(left(), right()) :: left() | right()

Returns the smallest of the two given terms, if terms are equal - then the first one is returned

Examples

iex> Comp.min(1, 1)
1
iex> Comp.min(1, 2)
1
iex> Comp.min(2, 1)
1

@spec not_equal?(left(), right()) :: boolean()

Is left term not equal to right term?

Examples

iex> Comp.not_equal?(1, 1)
false
iex> Comp.not_equal?(1, :hello)
true

@spec reset_dispatch() :: :ok

Discards every memoized type-pair dispatch.

Only needed when a comparator is defined after a pair has already been resolved, which in a release cannot happen.