module ActiveSupport::CoreExtensions::String::Multibyte

def chars
  ActiveSupport::Deprecation.warn('String#chars has been deprecated in favor of String#mb_chars.', caller)
  mb_chars
end

them), returns false otherwise.
Returns true if the string has UTF-8 semantics (a String used for purely byte resources is unlikely to have

def is_utf8?
  ActiveSupport::Multibyte::Chars.consumes?(self)
end

:nodoc

def is_utf8? #:nodoc
  case encoding
  when Encoding::UTF_8
    valid_encoding?
  when Encoding::ASCII_8BIT, Encoding::US_ASCII
    dup.force_encoding(Encoding::UTF_8).valid_encoding?
  else
    false
  end
end

information about how to change the default Multibyte behaviour see ActiveSupport::Multibyte.
For more information about the methods defined on the Chars proxy see ActiveSupport::Multibyte::Chars. For

object. Interoperability problems can be resolved easily with a +to_s+ call.
String and Char work like expected. The bang! methods change the internal string representation in the Chars
The Chars object tries to be as interchangeable with String objects as possible: sorting and comparing between

== Interoperability and configuration

name.mb_chars.reverse.length #=> 12

method chaining on the result of any of these methods.
All the methods on the Chars proxy which normally return a string will return a Chars object. This allows

== Method chaining

it becomes easy to run one version of your code on multiple Ruby versions.
In Ruby 1.9 and newer +mb_chars+ returns +self+ because String is (mostly) encoding aware. This means that

name.mb_chars.length #=> 12
name.mb_chars.reverse.to_s #=> "rellüM sualC"

name.length #=> 13
name.reverse #=> "rell??M sualC"
name = 'Claus Müller'

class. If the proxy class doesn't respond to a certain method, it's forwarded to the encapsuled string.
encapsulates the original string. A Unicode safe version of all the String methods are defined on this proxy
In Ruby 1.8 and older it creates and returns an instance of the ActiveSupport::Multibyte::Chars class which

+mb_chars+ is a multibyte safe proxy for string methods.

== Multibyte proxy

def mb_chars
  if ActiveSupport::Multibyte.proxy_class.wants?(self)
    ActiveSupport::Multibyte.proxy_class.new(self)
  else
    self
  end
end

:nodoc

def mb_chars #:nodoc
  self
end