ActiveSupport::Multibyte::Chars (original) (raw)

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

Methods

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D

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T

Included Modules

Attributes

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

Class Public methods

Creates a new Chars instance by wrapping string.

Source: show | on GitHub

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

Instance Public methods

Performs composition on all the characters.

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

Source: show | on GitHub

def compose chars(Unicode.compose(@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

Source: show | on GitHub

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

Returns the number of grapheme clusters in the string.

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

Source: show | on GitHub

def grapheme_length @wrapped_string.grapheme_clusters.length 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"

Source: show | on GitHub

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

Forward all undefined methods to the wrapped string.

Source: show | on GitHub

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

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: show | on GitHub

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

Reverses all characters in the string.

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

Source: show | on GitHub

def reverse chars(@wrapped_string.grapheme_clusters.reverse.join) 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'

Source: show | on GitHub

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

Source: show | on GitHub

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

tidy_bytes(force = false)Link

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: show | on GitHub

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

Source: show | on GitHub

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