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Class: ActiveSupport::Multibyte::Chars

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Instance Chain:
self, Comparable
Inherits: Object
Defined in: activesupport/lib/active_support/multibyte/chars.rb

Overview

Chars enables you to work transparently with UTF-8 encoding in the Ruby ::String class without having extensive knowledge about the encoding. A Chars object accepts a string upon initialization and proxies ::String methods in an encoding safe manner. All the normal ::String methods are also implemented on the proxy.

::String methods are proxied through the Chars object, and can be accessed through the mb_chars method. Methods which would normally return a ::String object now return a Chars object so methods can be chained.

'The Perfect String  '.mb_chars.downcase.strip
# => #<ActiveSupport::Multibyte::Chars:0x007fdc434ccc10 @wrapped_string="the perfect string">

Chars objects are perfectly interchangeable with ::String objects as long as no explicit class checks are made. If certain methods do explicitly check the class, call #to_s before you pass chars objects to them.

bad.explicit_checking_method 'T'.mb_chars.downcase.to_s

The default Chars implementation assumes that the encoding of the string is UTF-8, if you want to handle different encodings you can write your own multibyte string handler and configure it through proxy_class.

class CharsForUTF32
  def size
    @wrapped_string.size / 4
  end

  def self.accepts?(string)
    string.length % 4 == 0
  end
end

ActiveSupport::Multibyte.proxy_class = CharsForUTF32

Class Method Summary

Instance Attribute Summary

Instance Method Summary

Constructor Details

.new(string) ⇒ Chars

Creates a new Chars instance by wrapping string.

[ GitHub ] 

  


# File 'activesupport/lib/active_support/multibyte/chars.rb', line 55



def initialize(string)
  @wrapped_string = string
  @wrapped_string.force_encoding(Encoding::UTF_8) unless @wrapped_string.frozen?
end


  







Dynamic Method Handling

  

    This class handles dynamic methods through the method_missing method




  

    #method_missing(method, *args, &block)  
  



  

    

Forward all undefined methods to the wrapped string.


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/multibyte/chars.rb', line 61



def method_missing(method, *args, &block)
  result = @wrapped_string.__send__(method, *args, &block)
  if method.end_with?("!")
    self if result
  else
    result.kind_of?(String) ? chars(result) : result
  end
end


  







Instance Attribute Details



  

    #to_s   (readonly)
  



  

    

Alias for #wrapped_string.


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/multibyte/chars.rb', line 49



alias to_s wrapped_string


  








  

    #to_str   (readonly)
  



  

    

Alias for #wrapped_string.


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/multibyte/chars.rb', line 50



alias to_str wrapped_string


  








  

    #wrapped_string   (readonly)
    Also known as: #to_s, #to_str
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/multibyte/chars.rb', line 48



attr_reader :wrapped_string


  







Instance Method Details



  

    #<=>  
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/multibyte/chars.rb', line 52



delegate :<=>, :=~, :match?, :acts_like_string?, to: :wrapped_string


  








  

    #=~  
  

  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/multibyte/chars.rb', line 52



delegate :<=>, :=~, :match?, :acts_like_string?, to: :wrapped_string


  








  

    #acts_like_string?  ⇒ Boolean 
  



  

    
  





  


  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/multibyte/chars.rb', line 52



delegate :<=>, :=~, :match?, :acts_like_string?, to: :wrapped_string


  








  

    #compose  
  



  

    

Performs composition on all the characters.



'é'.length                       # => 3
'é'.mb_chars.compose.to_s.length # => 2


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/multibyte/chars.rb', line 139



def compose
  chars(Unicode.compose(@wrapped_string.codepoints.to_a).pack("U*"))
end


  








  

    #decompose  
  



  

    

Performs canonical decomposition on all the characters.



'é'.length                         # => 2
'é'.mb_chars.decompose.to_s.length # => 3


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/multibyte/chars.rb', line 131



def decompose
  chars(Unicode.decompose(:canonical, @wrapped_string.codepoints.to_a).pack("U*"))
end


  








  

    #grapheme_length  
  



  

    

Returns the number of grapheme clusters in the string.



'क्षि'.mb_chars.length   # => 4
'क्षि'.mb_chars.grapheme_length # => 3


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/multibyte/chars.rb', line 147



def grapheme_length
  @wrapped_string.scan(/\X/).length
end


  








  

    #limit(limit)  
  



  

    

Limits the byte size of the string to a number of bytes without breaking characters. Usable when the storage for a string is limited for some reason.



'こんにちは'.mb_chars.limit(7).to_s # => "こん"


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/multibyte/chars.rb', line 114



def limit(limit)
  chars(@wrapped_string.truncate_bytes(limit, omission: nil))
end


  








  

    #match?  ⇒ Boolean 
  



  

    
  





  


  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/multibyte/chars.rb', line 52



delegate :<=>, :=~, :match?, :acts_like_string?, to: :wrapped_string


  








  

    #respond_to_missing?(method, include_private)  ⇒ Boolean 
  



  

    

Returns true if obj responds to the given method. Private methods are included in the search only if the optional second parameter evaluates to true.


  





  


  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/multibyte/chars.rb', line 73



def respond_to_missing?(method, include_private)
  @wrapped_string.respond_to?(method, include_private)
end


  








  

    #reverse  
  



  

    

Reverses all characters in the string.



'Café'.mb_chars.reverse.to_s # => 'éfaC'


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/multibyte/chars.rb', line 105



def reverse
  chars(@wrapped_string.scan(/\X/).reverse.join)
end


  








  

    #slice!(*args)  
  



  

    

Works like String#slice!, but returns an instance of Chars, or nil if the string was not modified. The string will not be modified if the range given is out of bounds



string = 'Welcome'
string.mb_chars.slice!(3)    # => #<ActiveSupport::Multibyte::Chars:0x000000038109b8 @wrapped_string="c">
string # => 'Welome'
string.mb_chars.slice!(0..3) # => #<ActiveSupport::Multibyte::Chars:0x00000002eb80a0 @wrapped_string="Welo">
string # => 'me'


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/multibyte/chars.rb', line 95



def slice!(*args)
  string_sliced = @wrapped_string.slice!(*args)
  if string_sliced
    chars(string_sliced)
  end
end


  








  

    #split(*args)  
  



  

    

Works just like String#split, with the exception that the items in the resulting list are Chars instances instead of ::String. This makes chaining methods easier.



'Café périferôl'.mb_chars.split(/é/).map { |part| part.upcase.to_s } # => ["CAF", " P", "RIFERÔL"]


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/multibyte/chars.rb', line 82



def split(*args)
  @wrapped_string.split(*args).map { |i| self.class.new(i) }
end


  








  

    #tidy_bytes(force = false)  
  



  

    

Replaces all ISO-8859-1 or CP1252 characters by their UTF-8 equivalent resulting in a valid UTF-8 string.



Passing true will forcibly tidy all bytes, assuming that the string’s encoding is entirely CP1252 or ISO-8859-1.


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/multibyte/chars.rb', line 156



def tidy_bytes(force = false)
  chars(Unicode.tidy_bytes(@wrapped_string, force))
end


  








  

    #titlecase  
  



  

    

Alias for #titleize.


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/multibyte/chars.rb', line 125



alias_method :titlecase, :titleize


  








  

    #titleize  
    Also known as: #titlecase
  



  

    

Capitalizes the first letter of every word, when possible.



"ÉL QUE SE ENTERÓ".mb_chars.titleize.to_s    # => "Él Que Se Enteró"
"日本語".mb_chars.titleize.to_s               # => "日本語"


  



  [ GitHub ]


  

  


# File 'activesupport/lib/active_support/multibyte/chars.rb', line 122



def titleize
  chars(downcase.to_s.gsub(/\b('?\S)/u) { $1.upcase })
end