Adding String.contains?

Detect whether a string contains another string.

Author: josephwilk

lib/elixir/lib/string.ex

@@ -845,4 +845,29 @@ defmodule String do
 
   def ends_with?(string, suffix), do: ends_with?(string, [ suffix ])
 
+  @doc """
+  Returns true if `string` contains match, otherwise false.
+  `matches` can be either a single match of a list of matches.
+
+  ## Examples
+
+      iex> String.contains? "elixir of life", "of"
+      true
+      iex> String.contains? "elixir of life", ["life", "death"]
+      true
+      iex> String.contains? "elixir of life", ["death", "mercury"]
+      false
+
+  """
+  def contains?(string, matches) when is_list(matches) do
+    Enum.any? matches, fn match ->
+      case :binary.matches(string, match) do
+        [_] -> true
+        []  -> false
+      end
+    end
+  end
+
+  def contains?(string, match), do: contains?(string, [ match ])
+
 end

lib/elixir/test/elixir/string_test.exs

@@ -303,4 +303,13 @@ defmodule StringTest do
     refute String.ends_with? "エリクシア", "仙丹"
   end
 
+  test :contains? do
+    assert String.contains? "elixir of life", "of"
+    assert String.contains? "エリクシア", "シ"
+    assert String.contains? "elixir of life", ["mercury", "life"]
+    refute String.contains? "exlixir of life", "death"
+    refute String.contains? "エリクシア", "仙"
+    refute String.contains? "elixir of life", ["death", "mercury", "eternal life"]
+  end
+
 end