Implement Chars#swapcase.

2 files changed, 16 insertions, 0 deletions

diff --git a/activesupport/lib/active_support/multibyte/chars.rb b/activesupport/lib/active_support/multibyte/chars.rb
index 99b974e4a7..d69bfefc23 100644
--- a/activesupport/lib/active_support/multibyte/chars.rb
+++ b/activesupport/lib/active_support/multibyte/chars.rb
@@ -118,6 +118,14 @@ module ActiveSupport #:nodoc:
         chars Unicode.downcase(@wrapped_string)
       end
 
+      # Converts characters in the string to the opposite case.
+      #
+      # Example:
+      #    'El Cañón".mb_chars.swapcase.to_s # => "eL cAÑÓN"
+      def swapcase
+        chars Unicode.swapcase(@wrapped_string)
+      end
+
       # Converts the first character to uppercase and the remainder to lowercase.
       #
       # Example:
diff --git a/activesupport/lib/active_support/multibyte/unicode.rb b/activesupport/lib/active_support/multibyte/unicode.rb
index 94fb0a48aa..a0a8f3c97e 100644
--- a/activesupport/lib/active_support/multibyte/unicode.rb
+++ b/activesupport/lib/active_support/multibyte/unicode.rb
@@ -293,9 +293,17 @@ module ActiveSupport
         apply_mapping string, :uppercase_mapping
       end
 
+      def swapcase(string)
+        apply_mapping string, :swapcase_mapping
+      end
+
       # Holds data about a codepoint in the Unicode database
       class Codepoint
         attr_accessor :code, :combining_class, :decomp_type, :decomp_mapping, :uppercase_mapping, :lowercase_mapping
+
+        def swapcase_mapping
+          uppercase_mapping > 0 ? uppercase_mapping : lowercase_mapping
+        end
       end
 
       # Holds static data from the Unicode database