Add abs function. 1.3.0

lib/rational.ex

@@ -16,7 +16,7 @@ defmodule Rational do
       Rational
 
       iex> ~n(2/12)
-      2.0/12.0
+      1/6
 
       iex> ~n(1/4) * ~n(2/3)
       1/6
@@ -34,9 +34,9 @@ defmodule Rational do
 
   defmacro __using__(_opts) do
     quote do
-      import Kernel, except: [+: 2, -: 2, *: 2, /: 2, **: 2]
+      import Kernel, except: [+: 2, -: 2, *: 2, /: 2, **: 2, abs: 1]
       import RationalMath
-      import Rational
+      import Rational, only: [sigil_n: 2, parse: 1, compare: 2]
     end
   end
 
@@ -115,6 +115,7 @@ defmodule Rational do
     end
   end
 
+  @doc false
   @spec op(number(), number(), operator()) :: number()
   def op(a, b, op) when is_number(a) and is_number(b) do
     {res, _} =
@@ -188,6 +189,9 @@ defmodule Rational do
     |> result()
   end
 
+  def op(a, :abs) when is_rational(a), do: %Rational{num: abs(a.num), denom: abs(a.denom)}
+  def op(a, :abs) when is_number(a),do: abs(a)
+
   defp gcd(a, 0), do: abs(a)
   defp gcd(a, b), do: gcd(b, rem(a, b))
 

lib/rational_math.ex

@@ -8,6 +8,7 @@ defprotocol RationalMath do
   def a * b
   def a / b
   def a ** b
+  def abs(a)
 end
 
 defimpl RationalMath, for: [Rational, Integer, Float] do
@@ -16,4 +17,5 @@ defimpl RationalMath, for: [Rational, Integer, Float] do
   def a * b, do: Rational.op(a, b, :*)
   def a / b, do: Rational.op(a, b, :/)
   def a ** b, do: Rational.op(a, b, :**)
+  def abs(a), do: Rational.op(a, :abs)
 end

mix.exs

@@ -4,7 +4,7 @@ defmodule Rational.MixProject do
   def project do
     [
       app: :rational,
-      version: "1.2.0",
+      version: "1.3.0",
       elixir: "~> 1.13",
       start_permanent: Mix.env() == :prod,
       description: description(),