ActiveSupport::Multibyte::Chars

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.normalize
# => #<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

Methods

capitalize
compose
consumes?
decompose
downcase
grapheme_length
limit
method_missing
new
normalize
respond_to_missing?
reverse
slice!
split
swapcase
tidy_bytes
titlecase
titleize
upcase

Included Modules

Comparable

Attributes

[R]	to_s
[R]	to_str
[R]	wrapped_string

Class Public methods

consumes?(string)

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

📝 Source code

# File activesupport/lib/active_support/multibyte/chars.rb, line 79
      def self.consumes?(string)
        string.encoding == Encoding::UTF_8
      end

🔎 See on GitHub

new(string)

Creates a new Chars instance by wrapping string.

📝 Source code

# 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

🔎 See on GitHub

Instance Public methods

capitalize()

Converts the first character to uppercase and the remainder to lowercase.

'über'.mb_chars.capitalize.to_s # => "Über"

📝 Source code

# File activesupport/lib/active_support/multibyte/chars.rb, line 148
      def capitalize
        (slice(0) || chars("")).upcase + (slice(1..-1) || chars("")).downcase
      end

🔎 See on GitHub

compose()

Performs composition on all the characters.

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

📝 Source code

# File activesupport/lib/active_support/multibyte/chars.rb, line 184
      def compose
        chars(Unicode.compose(@wrapped_string.codepoints.to_a).pack("U*"))
      end

🔎 See on GitHub

decompose()

Performs canonical decomposition on all the characters.

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

📝 Source code

# File activesupport/lib/active_support/multibyte/chars.rb, line 176
      def decompose
        chars(Unicode.decompose(:canonical, @wrapped_string.codepoints.to_a).pack("U*"))
      end

🔎 See on GitHub

downcase()

Converts characters in the string to lowercase.

'VĚDA A VÝZKUM'.mb_chars.downcase.to_s # => "věda a výzkum"

📝 Source code

# File activesupport/lib/active_support/multibyte/chars.rb, line 134
      def downcase
        chars Unicode.downcase(@wrapped_string)
      end

🔎 See on GitHub

grapheme_length()

Returns the number of grapheme clusters in the string.

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

📝 Source code

# File activesupport/lib/active_support/multibyte/chars.rb, line 192
      def grapheme_length
        Unicode.unpack_graphemes(@wrapped_string).length
      end

🔎 See on GitHub

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"

📝 Source code

# File activesupport/lib/active_support/multibyte/chars.rb, line 120
      def limit(limit)
        slice(0...translate_offset(limit))
      end

🔎 See on GitHub

method_missing(method, *args, &block)

Forward all undefined methods to the wrapped string.

📝 Source code

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

🔎 See on GitHub

normalize(form = nil)

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

📝 Source code

# File activesupport/lib/active_support/multibyte/chars.rb, line 168
      def normalize(form = nil)
        chars(Unicode.normalize(@wrapped_string, form))
      end

🔎 See on GitHub

respond_to_missing?(method, include_private)

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.

📝 Source code

# 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

🔎 See on GitHub

reverse()

Reverses all characters in the string.

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

📝 Source code

# File activesupport/lib/active_support/multibyte/chars.rb, line 111
      def reverse
        chars(Unicode.unpack_graphemes(@wrapped_string).reverse.flatten.pack("U*"))
      end

🔎 See on GitHub

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'

📝 Source code

# File activesupport/lib/active_support/multibyte/chars.rb, line 101
      def slice!(*args)
        string_sliced = @wrapped_string.slice!(*args)
        if string_sliced
          chars(string_sliced)
        end
      end

🔎 See on GitHub

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"]

📝 Source code

# File activesupport/lib/active_support/multibyte/chars.rb, line 88
      def split(*args)
        @wrapped_string.split(*args).map { |i| self.class.new(i) }
      end

🔎 See on GitHub

swapcase()

Converts characters in the string to the opposite case.

'El Cañón'.mb_chars.swapcase.to_s # => "eL cAÑÓN"

📝 Source code

# File activesupport/lib/active_support/multibyte/chars.rb, line 141
      def swapcase
        chars Unicode.swapcase(@wrapped_string)
      end

🔎 See on GitHub

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.

📝 Source code

# File activesupport/lib/active_support/multibyte/chars.rb, line 201
      def tidy_bytes(force = false)
        chars(Unicode.tidy_bytes(@wrapped_string, force))
      end

🔎 See on GitHub

titlecase()

Alias for: titleize

titleize()

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

📝 Source code

# File activesupport/lib/active_support/multibyte/chars.rb, line 156
      def titleize
        chars(downcase.to_s.gsub(/\b('?\S)/u) { Unicode.upcase($1) })
      end

🔎 See on GitHub

upcase()

Converts characters in the string to uppercase.

'Laurent, où sont les tests ?'.mb_chars.upcase.to_s # => "LAURENT, OÙ SONT LES TESTS ?"

📝 Source code

# File activesupport/lib/active_support/multibyte/chars.rb, line 127
      def upcase
        chars Unicode.upcase(@wrapped_string)
      end

🔎 See on GitHub

ActiveSupport::Multibyte::Chars < Object

Methods

Included Modules

Attributes

Class Public methods

consumes?(string)

new(string)

Instance Public methods

capitalize()

compose()

decompose()

downcase()

grapheme_length()

limit(limit)

method_missing(method, *args, &block)

normalize(form = nil)

respond_to_missing?(method, include_private)

reverse()

slice!(*args)

split(*args)

swapcase()

tidy_bytes(force = false)

titlecase()

titleize()

upcase()