class ActiveSupport::Multibyte::Chars

Parent:: Object
Included modules:

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 ActiveSupport::Multibyte.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

Attributes

to_s[R]

to_str[R]

wrapped_string[R]

Public Class Methods

consumes?(string) Show source

# File activesupport/lib/active_support/multibyte/chars.rb, line 78
      def self.consumes?(string)
        ActiveSupport::Deprecation.warn(<<-MSG.squish)
          ActiveSupport::Multibyte::Chars.consumes? is deprecated and will be
          removed from Rails 6.1. Use string.is_utf8? instead.
        MSG

        string.encoding == Encoding::UTF_8
      end

Returns true when the proxy class can handle the string. Returns false otherwise.

new(string) Show source

# File activesupport/lib/active_support/multibyte/chars.rb, line 54
def initialize(string)
  @wrapped_string = string
  @wrapped_string.force_encoding(Encoding::UTF_8) unless @wrapped_string.frozen?
end

Creates a new Chars instance by wrapping string.

Public Instance Methods

compose() Show source

# File activesupport/lib/active_support/multibyte/chars.rb, line 177
def compose
  chars(Unicode.compose(@wrapped_string.codepoints.to_a).pack("U*"))
end

Performs composition on all the characters.

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

decompose() Show source

# File activesupport/lib/active_support/multibyte/chars.rb, line 169
def decompose
  chars(Unicode.decompose(:canonical, @wrapped_string.codepoints.to_a).pack("U*"))
end

Performs canonical decomposition on all the characters.

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

grapheme_length() Show source

# File activesupport/lib/active_support/multibyte/chars.rb, line 185
def grapheme_length
  @wrapped_string.scan(/\X/).length
end

Returns the number of grapheme clusters in the string.

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

limit(limit) Show source

# File activesupport/lib/active_support/multibyte/chars.rb, line 124
def limit(limit)
  truncate_bytes(limit, omission: nil)
end

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"

method_missing(method, *args, &block) Show source

# File activesupport/lib/active_support/multibyte/chars.rb, line 60
def method_missing(method, *args, &block)
  result = @wrapped_string.__send__(method, *args, &block)
  if /!$/.match?(method)
    self if result
  else
    result.kind_of?(String) ? chars(result) : result
  end
end

Forward all undefined methods to the wrapped string.

normalize(form = nil) Show source

# File activesupport/lib/active_support/multibyte/chars.rb, line 144
      def normalize(form = nil)
        form ||= Unicode.default_normalization_form

        # See https://www.unicode.org/reports/tr15, Table 1
        if alias_form = Unicode::NORMALIZATION_FORM_ALIASES[form]
          ActiveSupport::Deprecation.warn(<<-MSG.squish)
            ActiveSupport::Multibyte::Chars#normalize is deprecated and will be
            removed from Rails 6.1. Use #unicode_normalize(:#{alias_form}) instead.
          MSG

          send(:unicode_normalize, alias_form)
        else
          ActiveSupport::Deprecation.warn(<<-MSG.squish)
            ActiveSupport::Multibyte::Chars#normalize is deprecated and will be
            removed from Rails 6.1. Use #unicode_normalize instead.
          MSG

          raise ArgumentError, "#{form} is not a valid normalization variant", caller
        end
      end

Returns the KC normalization of the string by default. NFKC is considered the best normalization form for passing strings to databases and validations.

form - The form you want to normalize in. Should be one of the following: :c, :kc, :d, or :kd. Default is ActiveSupport::Multibyte::Unicode#default_normalization_form

respond_to_missing?(method, include_private) Show source

# File activesupport/lib/active_support/multibyte/chars.rb, line 72
def respond_to_missing?(method, include_private)
  @wrapped_string.respond_to?(method, include_private)
end

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.

reverse() Show source

# File activesupport/lib/active_support/multibyte/chars.rb, line 115
def reverse
  chars(@wrapped_string.scan(/\X/).reverse.join)
end

Reverses all characters in the string.

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

slice!(*args) Show source

# File activesupport/lib/active_support/multibyte/chars.rb, line 105
def slice!(*args)
  string_sliced = @wrapped_string.slice!(*args)
  if string_sliced
    chars(string_sliced)
  end
end

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'

split(*args) Show source

# File activesupport/lib/active_support/multibyte/chars.rb, line 92
def split(*args)
  @wrapped_string.split(*args).map { |i| self.class.new(i) }
end

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"]

tidy_bytes(force = false) Show source

# File activesupport/lib/active_support/multibyte/chars.rb, line 194
def tidy_bytes(force = false)
  chars(Unicode.tidy_bytes(@wrapped_string, force))
end

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.

titlecase()

Alias for: titleize

titleize() Show source

# File activesupport/lib/active_support/multibyte/chars.rb, line 132
def titleize
  chars(downcase.to_s.gsub(/\b('?\S)/u) { $1.upcase })
end

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"

Also aliased as: titlecase