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.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 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

.consumes?(string) ⇒ Boolean

Returns true when the proxy class can handle the string.
.new(string) ⇒ Chars constructor

Creates a new Chars instance by wrapping string.

Instance Attribute Summary

#to_s readonly

Alias for #wrapped_string.
#to_str readonly

Alias for #wrapped_string.
#wrapped_string (also: #to_s, #to_str) readonly

Instance Method Summary

#<=>
#=~
#acts_like_string? ⇒ Boolean
#capitalize

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

Performs composition on all the characters.
#decompose

Performs canonical decomposition on all the characters.
#downcase

Converts characters in the string to lowercase.
#grapheme_length

Returns the number of grapheme clusters in the string.
#limit(limit)

Limits the byte size of the string to a number of bytes without breaking characters.
#method_missing(method, *args, &block)

Forward all undefined methods to the wrapped string.
#normalize(form = nil)

Returns the KC normalization of the string by default.
#respond_to_missing?(method, include_private) ⇒ Boolean

Returns true if obj responds to the given method.
#reverse

Reverses all characters in the string.
#slice!(*args)

Works like String#slice!, but returns an instance of Chars, or nil if the string was not modified.
#split(*args)

Works just like String#split, with the exception that the items in the resulting list are Chars instances instead of ::String.
#swapcase

Converts characters in the string to the opposite case.
#tidy_bytes(force = false)

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

Alias for #titleize.
#titleize (also: #titlecase)

Capitalizes the first letter of every word, when possible.
#upcase

Converts characters in the string to uppercase.

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 /!$/.match?(method)
    self if result
  else
    result.kind_of?(String) ? chars(result) : result
  end
end

Class Method Details

.consumes?(string) ⇒ `Boolean`

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

[ GitHub ]

# File 'activesupport/lib/active_support/multibyte/chars.rb', line 79


def self.consumes?(string)
  string.encoding == Encoding::UTF_8
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 :<=>, :=~, :acts_like_string?, to: :wrapped_string

#=~

[ GitHub ]

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


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

#acts_like_string? ⇒ `Boolean`

[ GitHub ]

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


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

#capitalize

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

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

[ GitHub ]

# File 'activesupport/lib/active_support/multibyte/chars.rb', line 148


def capitalize
  (slice(0) || chars("")).upcase + (slice(1..-1) || chars("")).downcase
end

#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 184


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 176


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

#downcase

Converts characters in the string to lowercase.

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

[ GitHub ]

# File 'activesupport/lib/active_support/multibyte/chars.rb', line 134


def downcase
  chars Unicode.downcase(@wrapped_string)
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 192


def grapheme_length
  Unicode.unpack_graphemes(@wrapped_string).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 120


def limit(limit)
  slice(0...translate_offset(limit))
end

#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

[ GitHub ]

# File 'activesupport/lib/active_support/multibyte/chars.rb', line 168


def normalize(form = nil)
  chars(Unicode.normalize(@wrapped_string, form))
end

#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 111


def reverse
  chars(Unicode.unpack_graphemes(@wrapped_string).reverse.flatten.pack("U*"))
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 101


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 88


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

#swapcase

Converts characters in the string to the opposite case.

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

[ GitHub ]

# File 'activesupport/lib/active_support/multibyte/chars.rb', line 141


def swapcase
  chars Unicode.swapcase(@wrapped_string)
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 201


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 159


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 156


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

#upcase

Converts characters in the string to uppercase.

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

[ GitHub ]

# File 'activesupport/lib/active_support/multibyte/chars.rb', line 127


def upcase
  chars Unicode.upcase(@wrapped_string)
end

Class: ActiveSupport::Multibyte::Chars

Overview

Class Method Summary

Instance Attribute Summary

Instance Method Summary

Constructor Details

.new(string) ⇒ Chars

Dynamic Method Handling

#method_missing(method, *args, &block)

Class Method Details

.consumes?(string) ⇒ Boolean

Instance Attribute Details

#to_s (readonly)

#to_str (readonly)

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

Instance Method Details

#<=>

#=~

#acts_like_string? ⇒ Boolean

#capitalize

#compose

#decompose

#downcase

#grapheme_length

#limit(limit)

#normalize(form = nil)

#respond_to_missing?(method, include_private) ⇒ Boolean

#reverse

#slice!(*args)

#split(*args)

#swapcase

#tidy_bytes(force = false)

#titlecase

#titleize Also known as: #titlecase

#upcase

.new(string) ⇒ `Chars`

.consumes?(string) ⇒ `Boolean`

#acts_like_string? ⇒ `Boolean`

#respond_to_missing?(method, include_private) ⇒ `Boolean`