mb_chars is a multibyte safe proxy for string methods.
In Ruby 1.8 and older it creates and returns an instance of the ActiveSupport::Multibyte::Chars class which encapsulates the original string. A Unicode safe version of all the String methods are defined on this proxy class. If the proxy class doesn’t respond to a certain method, it’s forwarded to the encapsulated string.
name = 'Claus MÃ¼ller' name.reverse # => "rell??M sualC" name.length # => 13 name.mb_chars.reverse.to_s # => "rellÃ¼M sualC" name.mb_chars.length # => 12
All the methods on the Chars proxy which normally return a string will return a Chars object. This allows method chaining on the result of any of these methods.
name.mb_chars.reverse.length # => 12
Interoperability and configuration
The Chars object tries to be as interchangeable with String objects as possible: sorting and comparing between String and Char work like expected. The bang! methods change the internal string representation in the Chars object. Interoperability problems can be resolved easily with a to_s call.
# File activesupport/lib/active_support/core_ext/string/multibyte.rb, line 38 def mb_chars if ActiveSupport::Multibyte.proxy_class.consumes?(self) ActiveSupport::Multibyte.proxy_class.new(self) else self end end
ruby-1.9.2-p180 :007 > "àáâãäå".normalize(:kd) NoMethodError: undefined method `normalize' for "àáâãäå":String ruby-1.9.2-p180 :008 > "àáâãäå".mb_chars.normalize(:kd) => àáâãäå