String#dashcase library, test, and demo

.gitignore

@@ -14,3 +14,5 @@ Gemfile.lock
 *.gem
 .bundle/
 vendor/
+.ruby-version
+.ruby-gemset

demo/core/string/dashcase.md

@@ -0,0 +1,13 @@
+## String#dashcase
+
+    require 'facets/string/dashcase'
+
+Dashcase a string such that camelcase, underscores and spaces are
+replaced by dashes. This is similar to {#underscore},
+but with dashes instead of underscores.
+
+    'my_name'.dashcase.assert == 'my-name'
+
+    'MyName'.dashcase.assert == 'my-name'
+
+    'URI'.dashcase.assert == 'uri'

lib/core/facets/string/dashcase.rb

@@ -0,0 +1,21 @@
+class String
+
+  # Dashcase a string such that camelcase, underscores and spaces are
+  # replaced by dashes. This is similar to {#underscore},
+  # but with dashes instead of underscores.
+  #
+  #   "DashCase".dashcase         #=> "dash-case"
+  #   "Dash-Case".dashcase        #=> "dash-case"
+  #   "Dash Case".dashcase        #=> "dash-case"
+  #   "Dash  -  Case".dashcase    #=> "dash-case"
+
+  def dashcase
+    gsub(/([A-Z]+)([A-Z][a-z])/,'\1_\2').
+    gsub(/([a-z\d])([A-Z])/,'\1_\2').
+    tr('_', '-').
+    gsub(/\s/, '-').
+    gsub(/__+/, '-').
+    downcase
+  end
+
+end

test/core/string/test_dashcase.rb

@@ -0,0 +1,21 @@
+covers 'facets/string/dashcase'
+
+test_case String do
+
+  method :dashcase do
+
+    test "from camelcase" do
+      "DashCase".dashcase.assert == "dash-case"
+    end
+
+    test "containing an underscore" do
+      "Dash_Case".dashcase.assert == "dash-case"
+    end
+
+    test "containing spaces" do
+      "Dash Case".dashcase.assert == "dash-case"
+    end
+
+  end
+
+end