class ActiveSupport::Multibyte::Chars

Active Support 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
# => #<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

new (string, deprecation: true)

Source

# File lib/active_support/multibyte/chars.rb, line 56
def initialize(string, deprecation: true)
  if deprecation
    ActiveSupport.deprecator.warn(
      "ActiveSupport::Multibyte::Chars is deprecated and will be removed in Rails 8.2. " \
      "Use normal string methods instead."
    )
  end

  @wrapped_string = string
  if string.encoding != Encoding::UTF_8
    @wrapped_string = @wrapped_string.dup
    @wrapped_string.force_encoding(Encoding::UTF_8)
  end
end

Creates a new Chars instance by wrapping string.

Public Instance Methods

compose ()

Source

# File lib/active_support/multibyte/chars.rb, line 150
def compose
  chars(Unicode.compose(@wrapped_string.codepoints.to_a).pack("U*"))
end

Performs composition on all the characters.

'é'.length                       # => 1
'é'.mb_chars.compose.to_s.length # => 1

decompose ()

Source

# File lib/active_support/multibyte/chars.rb, line 142
def decompose
  chars(Unicode.decompose(:canonical, @wrapped_string.codepoints.to_a).pack("U*"))
end

Performs canonical decomposition on all the characters.

'é'.length                         # => 1
'é'.mb_chars.decompose.to_s.length # => 2

grapheme_length ()

Source

# File lib/active_support/multibyte/chars.rb, line 158
def grapheme_length
  @wrapped_string.grapheme_clusters.length
end

Returns the number of grapheme clusters in the string.

'क्षि'.mb_chars.length   # => 4
'क्षि'.mb_chars.grapheme_length # => 2

limit (limit)

Source

# File lib/active_support/multibyte/chars.rb, line 125
def limit(limit)
  chars(@wrapped_string.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, ...)

Source

# File lib/active_support/multibyte/chars.rb, line 72
def method_missing(method, ...)
  result = @wrapped_string.__send__(method, ...)
  if method.end_with?("!")
    self if result
  else
    result.kind_of?(String) ? chars(result) : result
  end
end

Forward all undefined methods to the wrapped string.

respond_to_missing? (method, include_private)

Source

# File lib/active_support/multibyte/chars.rb, line 84
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 ()

Source

# File lib/active_support/multibyte/chars.rb, line 116
def reverse
  chars(@wrapped_string.grapheme_clusters.reverse.join)
end

Reverses all characters in the string.

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

slice! (*args)

Source

# File lib/active_support/multibyte/chars.rb, line 106
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)

Source

# File lib/active_support/multibyte/chars.rb, line 93
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)

Source

# File lib/active_support/multibyte/chars.rb, line 167
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 ()

Source

# File lib/active_support/multibyte/chars.rb, line 133
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