add support for release candidates

.tool-versions

@@ -0,0 +1,2 @@
+elixir 1.14.0-otp-25
+erlang 25.0.4

config/config.exs

@@ -1,4 +1,4 @@
-use Mix.Config
+import Config
 
 #     config(:version_tasks, key: :value)
 #

lib/mix/tasks/next.ex

@@ -32,4 +32,20 @@ defmodule Mix.Tasks.Version.Next do
     {new_val, ""} = Integer.parse(major)
     "#{new_val + 1}.0.0"
   end
+
+  def uptick([major, minor, patch], "rc") do
+    {major, ""} = Integer.parse(major)
+
+    {major, minor, patch, rc_patch} =
+      case Integer.parse(patch) do
+        {_patch_val, ""} ->
+          {major + 1, 0, 0, "rc0"}
+
+        {patch_val, "-rc" <> existing_rc} ->
+          {rc_val, ""} = Integer.parse(existing_rc)
+          {major, minor, patch_val, "rc#{rc_val + 1}"}
+      end
+
+    "#{major}.#{minor}.#{patch}-#{rc_patch}"
+  end
 end

lib/mix/tasks/rc.ex

@@ -0,0 +1,26 @@
+defmodule Mix.Tasks.Version.Rc do
+  use Mix.Task
+  use VersionTasks.FnExpr
+  alias Mix.Tasks.Version.Current
+
+  @shortdoc "Return RC number (so return '1' for version '1.2.3-rc1'"
+  def run(_) do
+    calc() |> IO.puts()
+  end
+
+  def calc(), do: calc(Current.calc())
+
+  def calc(version) do
+    version
+    |> String.split(".")
+    |> name
+  end
+
+  defp name([_, _, patch]) do 
+    case Integer.parse(patch) do
+      {_patch_val, ""} -> "0"
+      {_patch_val, "-rc" <> existing_rc} -> existing_rc
+    end
+  end
+  defp name(_), do: ""
+end

mix.exs

@@ -28,7 +28,7 @@ defmodule VersionTasks.Mixfile do
     [
       app: @app,
       version: @version,
-      elixir: "~> 1.11",
+      elixir: "~> 1.14",
       name: "VersionTasks",
       description: "A suite of mix tasks for managing your libs version numbers with git and hex",
       package: @package,

test/tasks/rc_test.exs

@@ -0,0 +1,12 @@
+defmodule Mix.Tasks.Version.RcTest do
+  use ExUnit.Case
+  alias Mix.Tasks.Version.Rc
+
+  test "calc" do
+    assert "0" == Rc.calc("1.2.3")
+    assert "0" == Rc.calc("2.0.0")
+    assert "0" == Rc.calc("3.1.0-rc0")
+    assert "1" == Rc.calc("3.1.0-rc1")
+    assert "" == Rc.calc("")
+  end
+end