First commit. String with underscore

README.md

@@ -0,0 +1,4 @@
+Crutches
+=======
+
+The start of an Elixir ~~ripoff~~ port to the ActiveSupport Ruby gem.

config/config.exs

@@ -0,0 +1,24 @@
+# This file is responsible for configuring your application
+# and its dependencies with the aid of the Mix.Config module.
+use Mix.Config
+
+# This configuration is loaded before any dependency and is restricted
+# to this project. If another project depends on this project, this
+# file won't be loaded nor affect the parent project. For this reason,
+# if you want to provide default values for your application for third-
+# party users, it should be done in your mix.exs file.
+
+# Sample configuration:
+#
+#     config :logger, :console,
+#       level: :info,
+#       format: "$date $time [$level] $metadata$message\n",
+#       metadata: [:user_id]
+
+# It is also possible to import configuration files, relative to this
+# directory. For example, you can emulate configuration per environment
+# by uncommenting the line below and defining dev.exs, test.exs and such.
+# Configuration from the imported file will override the ones defined
+# here (which is why it is important to import them last).
+#
+#     import_config "#{Mix.env}.exs"

lib/crutches.ex

@@ -0,0 +1,2 @@
+defmodule Crutches do
+end

lib/crutches/string.ex

@@ -0,0 +1,14 @@
+defmodule Crutches.String do
+  def underscore(camel_case_string) do
+    camel_case_string
+      |> regex_replace(~r/\./, "/")
+      |> regex_replace(~r/([A-Z]+)([A-Z][a-z])/, "\\1_\\2")
+      |> regex_replace(~r/([a-z\d])([A-Z])/, "\\1_\\2")
+      |> regex_replace(~r/-/, "_")
+      |> String.downcase
+  end
+
+  defp regex_replace(string, regex, replace) do
+    Regex.replace(regex, string, replace)
+  end
+end

mix.exs

@@ -0,0 +1,32 @@
+defmodule Crutches.Mixfile do
+  use Mix.Project
+
+  def project do
+    [app: :crutches,
+     version: "0.0.1",
+     elixir: "~> 1.0",
+     build_embedded: Mix.env == :prod,
+     start_permanent: Mix.env == :prod,
+     deps: deps]
+  end
+
+  # Configuration for the OTP application
+  #
+  # Type `mix help compile.app` for more information
+  def application do
+    [applications: [:logger]]
+  end
+
+  # Dependencies can be Hex packages:
+  #
+  #   {:mydep, "~> 0.3.0"}
+  #
+  # Or git/path repositories:
+  #
+  #   {:mydep, git: "https://github.com/elixir-lang/mydep.git", tag: "0.1.0"}
+  #
+  # Type `mix help deps` for more examples and options
+  defp deps do
+    []
+  end
+end

test/crutches/string_test.exs

@@ -0,0 +1,40 @@
+defmodule Crutches.StringTest do
+  alias Crutches.String
+  use ExUnit.Case
+
+  def compare string_pairs do
+    string_pairs |> Enum.each fn([camel_case, underscore]) ->
+      assert underscore == String.underscore camel_case
+    end
+  end
+
+  test :camel_to_underscore do
+    [
+      ["Product",               "product"],
+      ["SpecialGuest",          "special_guest"],
+      ["ApplicationController", "application_controller"],
+      ["Area51Controller",      "area51_controller"]
+    ]
+    |> compare
+  end
+
+  test :camel_to_underscore_without_reverse do
+    [
+      ["HTMLTidy",           "html_tidy"],
+      ["HTMLTidyGenerator",  "html_tidy_generator"],
+      ["FreeBSD",            "free_bsd"],
+      ["HTML",               "html"],
+      ["ForceXMLController", "force_xml_controller"]
+    ]
+    |> compare
+  end
+
+  test :camel_with_module_to_underscore_with_slash do
+    [
+      ["Admin.Product",                    "admin/product"],
+      ["Users.Commission.Department",      "users/commission/department"],
+      ["UsersSection.CommissionDepartment","users_section/commission_department"]
+    ]
+    |> compare
+  end
+end

test/test_helper.exs

@@ -0,0 +1 @@
+ExUnit.start()