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 #=> "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
Included Modules
Constants
HANGUL_SBASE = 0xAC00
  Hangul character boundaries and properties
HANGUL_LBASE = 0x1100
HANGUL_VBASE = 0x1161
HANGUL_TBASE = 0x11A7
HANGUL_LCOUNT = 19
HANGUL_VCOUNT = 21
HANGUL_TCOUNT = 28
HANGUL_NCOUNT = HANGUL_VCOUNT * HANGUL_TCOUNT
HANGUL_SCOUNT = 11172
HANGUL_SLAST = HANGUL_SBASE + HANGUL_SCOUNT
HANGUL_JAMO_FIRST = 0x1100
HANGUL_JAMO_LAST = 0x11FF
UNICODE_WHITESPACE = [ (0x0009..0x000D).to_a, # White_Space # Cc [5] <control-0009>..<control-000D> 0x0020, # White_Space # Zs SPACE 0x0085, # White_Space # Cc <control-0085> 0x00A0, # White_Space # Zs NO-BREAK SPACE 0x1680, # White_Space # Zs OGHAM SPACE MARK 0x180E, # White_Space # Zs MONGOLIAN VOWEL SEPARATOR (0x2000..0x200A).to_a, # White_Space # Zs [11] EN QUAD..HAIR SPACE 0x2028, # White_Space # Zl LINE SEPARATOR 0x2029, # White_Space # Zp PARAGRAPH SEPARATOR 0x202F, # White_Space # Zs NARROW NO-BREAK SPACE 0x205F, # White_Space # Zs MEDIUM MATHEMATICAL SPACE 0x3000, # White_Space # Zs IDEOGRAPHIC SPACE ].flatten.freeze
  All the unicode whitespace
UNICODE_LEADERS_AND_TRAILERS = UNICODE_WHITESPACE + [65279]
  BOM (byte order mark) can also be seen as whitespace, it‘s a non-rendering character used to distinguish between little and big endian. This is not an issue in utf-8, so it must be ignored.
UNICODE_TRAILERS_PAT = /(#{codepoints_to_pattern(UNICODE_LEADERS_AND_TRAILERS)})+\Z/
UNICODE_LEADERS_PAT = /\A(#{codepoints_to_pattern(UNICODE_LEADERS_AND_TRAILERS)})+/
UTF8_PAT = ActiveSupport::Multibyte::VALID_CHARACTER['UTF-8']
Attributes
[R] wrapped_string
Public Class methods
compose_codepoints(codepoints)

Compose decomposed characters to the composed form.

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 577
577:         def compose_codepoints(codepoints)
578:           pos = 0
579:           eoa = codepoints.length - 1
580:           starter_pos = 0
581:           starter_char = codepoints[0]
582:           previous_combining_class = -1
583:           while pos < eoa
584:             pos += 1
585:             lindex = starter_char - HANGUL_LBASE
586:             # -- Hangul
587:             if 0 <= lindex and lindex < HANGUL_LCOUNT
588:               vindex = codepoints[starter_pos+1] - HANGUL_VBASE rescue vindex = -1
589:               if 0 <= vindex and vindex < HANGUL_VCOUNT
590:                 tindex = codepoints[starter_pos+2] - HANGUL_TBASE rescue tindex = -1
591:                 if 0 <= tindex and tindex < HANGUL_TCOUNT
592:                   j = starter_pos + 2
593:                   eoa -= 2
594:                 else
595:                   tindex = 0
596:                   j = starter_pos + 1
597:                   eoa -= 1
598:                 end
599:                 codepoints[starter_pos..j] = (lindex * HANGUL_VCOUNT + vindex) * HANGUL_TCOUNT + tindex + HANGUL_SBASE
600:               end
601:               starter_pos += 1
602:               starter_char = codepoints[starter_pos]
603:             # -- Other characters
604:             else
605:               current_char = codepoints[pos]
606:               current = UCD.codepoints[current_char]
607:               if current.combining_class > previous_combining_class
608:                 if ref = UCD.composition_map[starter_char]
609:                   composition = ref[current_char]
610:                 else
611:                   composition = nil
612:                 end
613:                 unless composition.nil?
614:                   codepoints[starter_pos] = composition
615:                   starter_char = composition
616:                   codepoints.delete_at pos
617:                   eoa -= 1
618:                   pos -= 1
619:                   previous_combining_class = -1
620:                 else
621:                   previous_combining_class = current.combining_class
622:                 end
623:               else
624:                 previous_combining_class = current.combining_class
625:               end
626:               if current.combining_class == 0
627:                 starter_pos = pos
628:                 starter_char = codepoints[pos]
629:               end
630:             end
631:           end
632:           codepoints
633:         end
consumes?(string)

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

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 123
123:       def self.consumes?(string)
124:         # Unpack is a little bit faster than regular expressions.
125:         string.unpack('U*')
126:         true
127:       rescue ArgumentError
128:         false
129:       end
decompose_codepoints(type, codepoints)

Decompose composed characters to the decomposed form.

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 556
556:         def decompose_codepoints(type, codepoints)
557:           codepoints.inject([]) do |decomposed, cp|
558:             # if it's a hangul syllable starter character
559:             if HANGUL_SBASE <= cp and cp < HANGUL_SLAST
560:               sindex = cp - HANGUL_SBASE
561:               ncp = [] # new codepoints
562:               ncp << HANGUL_LBASE + sindex / HANGUL_NCOUNT
563:               ncp << HANGUL_VBASE + (sindex % HANGUL_NCOUNT) / HANGUL_TCOUNT
564:               tindex = sindex % HANGUL_TCOUNT
565:               ncp << (HANGUL_TBASE + tindex) unless tindex == 0
566:               decomposed.concat ncp
567:             # if the codepoint is decomposable in with the current decomposition type
568:             elsif (ncp = UCD.codepoints[cp].decomp_mapping) and (!UCD.codepoints[cp].decomp_type || type == :compatability)
569:               decomposed.concat decompose_codepoints(type, ncp.dup)
570:             else
571:               decomposed << cp
572:             end
573:           end
574:         end
g_pack(unpacked)

Reverse operation of g_unpack.

Example: 

  Chars.g_pack(Chars.g_unpack('क्षि')) #=> 'क्षि'

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 527
527:         def g_pack(unpacked)
528:           (unpacked.flatten).pack('U*')
529:         end
g_unpack(string)

Unpack the string at grapheme boundaries. Returns a list of character lists.

Example: 

  Chars.g_unpack('क्षि') #=> [[2325, 2381], [2359], [2367]]
  Chars.g_unpack('Café') #=> [[67], [97], [102], [233]]

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 493
493:         def g_unpack(string)
494:           codepoints = u_unpack(string)
495:           unpacked = []
496:           pos = 0
497:           marker = 0
498:           eoc = codepoints.length
499:           while(pos < eoc)
500:             pos += 1
501:             previous = codepoints[pos-1]
502:             current = codepoints[pos]
503:             if (
504:                 # CR X LF
505:                 one = ( previous == UCD.boundary[:cr] and current == UCD.boundary[:lf] ) or
506:                 # L X (L|V|LV|LVT)
507:                 two = ( UCD.boundary[:l] === previous and in_char_class?(current, [:l,:v,:lv,:lvt]) ) or
508:                 # (LV|V) X (V|T)
509:                 three = ( in_char_class?(previous, [:lv,:v]) and in_char_class?(current, [:v,:t]) ) or
510:                 # (LVT|T) X (T)
511:                 four = ( in_char_class?(previous, [:lvt,:t]) and UCD.boundary[:t] === current ) or
512:                 # X Extend
513:                 five = (UCD.boundary[:extend] === current)
514:               )
515:             else
516:               unpacked << codepoints[marker..pos-1]
517:               marker = pos
518:             end
519:           end 
520:           unpacked
521:         end
in_char_class?(codepoint, classes)

Detect whether the codepoint is in a certain character class. Returns true when it‘s in the specified character class and false otherwise. Valid character classes are: :cr, :lf, :l, :v, :lv, :lvt and :t.

Primarily used by the grapheme cluster support.

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 484
484:         def in_char_class?(codepoint, classes)
485:           classes.detect { |c| UCD.boundary[c] === codepoint } ? true : false
486:         end
new(string)

Creates a new Chars instance by wrapping string.

[ show source ]

    # File activesupport/lib/active_support/multibyte/chars.rb, line 84
84:         def initialize(string)
85:           @wrapped_string = string
86:           @wrapped_string.force_encoding(Encoding::UTF_8) unless @wrapped_string.frozen?
87:         end
reorder_characters(codepoints)

Re-order codepoints so the string becomes canonical.

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 540
540:         def reorder_characters(codepoints)
541:           length = codepoints.length- 1
542:           pos = 0
543:           while pos < length do
544:             cp1, cp2 = UCD.codepoints[codepoints[pos]], UCD.codepoints[codepoints[pos+1]]
545:             if (cp1.combining_class > cp2.combining_class) && (cp2.combining_class > 0)
546:               codepoints[pos..pos+1] = cp2.code, cp1.code
547:               pos += (pos > 0 ? -1 : 1)
548:             else
549:               pos += 1
550:             end
551:           end
552:           codepoints
553:         end
tidy_bytes(string)

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

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 636
636:         def tidy_bytes(string)
637:           string.split(//u).map do |c|
638:             c.force_encoding(Encoding::ASCII) if c.respond_to?(:force_encoding)
639: 
640:             if !ActiveSupport::Multibyte::VALID_CHARACTER['UTF-8'].match(c)
641:               n = c.unpack('C')[0]
642:               n < 128 ? n.chr :
643:               n < 160 ? [UCD.cp1252[n] || n].pack('U') :
644:               n < 192 ? "\xC2" + n.chr : "\xC3" + (n-64).chr
645:             else
646:               c
647:             end
648:           end.join
649:         end
u_unpack(string)

Unpack the string at codepoints boundaries. Raises an EncodingError when the encoding of the string isn‘t valid UTF-8.

Example: 

  Chars.u_unpack('Café') #=> [67, 97, 102, 233]

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 471
471:         def u_unpack(string)
472:           begin
473:             string.unpack 'U*'
474:           rescue ArgumentError
475:             raise EncodingError, 'malformed UTF-8 character'
476:           end
477:         end
wants?(string)

Returns true if the Chars class can and should act as a proxy for the string string. Returns false otherwise.

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 118
118:       def self.wants?(string)
119:         $KCODE == 'UTF8' && consumes?(string)
120:       end
Public Instance methods
+(other)

Returns a new Chars object containing the other object concatenated to the string.

Example: 

  ('Café'.mb_chars + ' périferôl').to_s #=> "Café périferôl"

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 147
147:       def +(other)
148:         self << other
149:       end
<=>(other)

Returns -1, 0 or +1 depending on whether the Chars object is to be sorted before, equal or after the object on the right side of the operation. It accepts any object that implements to_s. See String#<=> for more details.

Example: 

  'é'.mb_chars <=> 'ü'.mb_chars #=> -1

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 139
139:       def <=>(other)
140:         @wrapped_string <=> other.to_s
141:       end
=~(other)

Like String#=~ only it returns the character offset (in codepoints) instead of the byte offset.

Example: 

  'Café périferôl'.mb_chars =~ /ô/ #=> 12

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 155
155:       def =~(other)
156:         translate_offset(@wrapped_string =~ other)
157:       end
[](*args)

Alias for slice

[]=(*args)

Like String#[]=, except instead of byte offsets you specify character offsets.

Example: 

  s = "Müller"
  s.mb_chars[2] = "e" # Replace character with offset 2
  s
  #=> "Müeler"

  s = "Müller"
  s.mb_chars[1, 2] = "ö" # Replace 2 characters at character offset 1
  s
  #=> "Möler"

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 231
231:       def []=(*args)
232:         replace_by = args.pop
233:         # Indexed replace with regular expressions already works
234:         if args.first.is_a?(Regexp)
235:           @wrapped_string[*args] = replace_by
236:         else
237:           result = self.class.u_unpack(@wrapped_string)
238:           if args[0].is_a?(Fixnum)
239:             raise IndexError, "index #{args[0]} out of string" if args[0] >= result.length
240:             min = args[0]
241:             max = args[1].nil? ? min : (min + args[1] - 1)
242:             range = Range.new(min, max)
243:             replace_by = [replace_by].pack('U') if replace_by.is_a?(Fixnum)
244:           elsif args.first.is_a?(Range)
245:             raise RangeError, "#{args[0]} out of range" if args[0].min >= result.length
246:             range = args[0]
247:           else
248:             needle = args[0].to_s
249:             min = index(needle)
250:             max = min + self.class.u_unpack(needle).length - 1
251:             range = Range.new(min, max)
252:           end
253:           result[range] = self.class.u_unpack(replace_by)
254:           @wrapped_string.replace(result.pack('U*'))
255:         end
256:       end
acts_like_string?()

Enable more predictable duck-typing on String-like classes. See Object#acts_like?.

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 112
112:       def acts_like_string?
113:         true
114:       end
capitalize()

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

Example: 

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

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 393
393:       def capitalize
394:         (slice(0) || chars('')).upcase + (slice(1..-1) || chars('')).downcase
395:       end
center(integer, padstr=' ')

Works just like String#center, only integer specifies characters instead of bytes.

Example: 

  "¾ cup".mb_chars.center(8).to_s
  #=> " ¾ cup  "

  "¾ cup".mb_chars.center(8, " ").to_s # Use non-breaking whitespace
  #=> " ¾ cup  "

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 293
293:       def center(integer, padstr=' ')
294:         justify(integer, :center, padstr)
295:       end
compose()

Performs composition on all the characters.

Example: 

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

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 435
435:       def compose
436:         chars(self.class.compose_codepoints(self.class.u_unpack(@wrapped_string)).pack('U*'))
437:       end
decompose()

Performs canonical decomposition on all the characters.

Example: 

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

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 426
426:       def decompose
427:         chars(self.class.decompose_codepoints(:canonical, self.class.u_unpack(@wrapped_string)).pack('U*'))
428:       end
downcase()

Convert characters in the string to lowercase.

Example: 

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

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 385
385:       def downcase
386:         apply_mapping :lowercase_mapping
387:       end
g_length()

Returns the number of grapheme clusters in the string.

Example: 

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

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 444
444:       def g_length
445:         self.class.g_unpack(@wrapped_string).length
446:       end
include?(other)

Returns true if contained string contains other. Returns false otherwise.

Example: 

  'Café'.mb_chars.include?('é') #=> true

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 188
188:       def include?(other)
189:         # We have to redefine this method because Enumerable defines it.
190:         @wrapped_string.include?(other)
191:       end
index(needle, offset=0)

Returns the position needle in the string, counting in codepoints. Returns nil if needle isn‘t found.

Example: 

  'Café périferôl'.mb_chars.index('ô') #=> 12
  'Café périferôl'.mb_chars.index(/\w/u) #=> 0

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 198
198:       def index(needle, offset=0)
199:         wrapped_offset = self.first(offset).wrapped_string.length
200:         index = @wrapped_string.index(needle, wrapped_offset)
201:         index ? (self.class.u_unpack(@wrapped_string.slice(0...index)).size) : nil
202:       end
insert(offset, fragment)

Inserts the passed string at specified codepoint offsets.

Example: 

  'Café'.mb_chars.insert(4, ' périferôl').to_s #=> "Café périferôl"

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 172
172:       def insert(offset, fragment)
173:         unpacked = self.class.u_unpack(@wrapped_string)
174:         unless offset > unpacked.length
175:           @wrapped_string.replace(
176:             self.class.u_unpack(@wrapped_string).insert(offset, *self.class.u_unpack(fragment)).pack('U*')
177:           )
178:         else
179:           raise IndexError, "index #{offset} out of string"
180:         end
181:         self
182:       end
length()

Alias for size

ljust(integer, padstr=' ')

Works just like String#ljust, only integer specifies characters instead of bytes.

Example: 

  "¾ cup".mb_chars.rjust(8).to_s
  #=> "¾ cup   "

  "¾ cup".mb_chars.rjust(8, " ").to_s # Use non-breaking whitespace
  #=> "¾ cup   "

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 280
280:       def ljust(integer, padstr=' ')
281:         justify(integer, :left, padstr)
282:       end
lstrip()

Strips entire range of Unicode whitespace from the left of the string.

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 303
303:       def lstrip
304:         chars(@wrapped_string.gsub(UNICODE_LEADERS_PAT, ''))
305:       end
method_missing(method, *args, &block)

Forward all undefined methods to the wrapped string.

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 95
 95:       def method_missing(method, *args, &block)
 96:         if method.to_s =~ /!$/
 97:           @wrapped_string.__send__(method, *args, &block)
 98:           self
 99:         else
100:           result = @wrapped_string.__send__(method, *args, &block)
101:           result.kind_of?(String) ? chars(result) : result
102:         end
103:       end
normalize(form=ActiveSupport::Multibyte.default_normalization_form)

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

  • str - The string to perform normalization on.
  • form - The form you want to normalize in. Should be one of the following: :c, :kc, :d, or :kd. Default is ActiveSupport::Multibyte.default_normalization_form

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 404
404:       def normalize(form=ActiveSupport::Multibyte.default_normalization_form)
405:         # See http://www.unicode.org/reports/tr15, Table 1
406:         codepoints = self.class.u_unpack(@wrapped_string)
407:         chars(case form
408:           when :d
409:             self.class.reorder_characters(self.class.decompose_codepoints(:canonical, codepoints))
410:           when :c
411:             self.class.compose_codepoints(self.class.reorder_characters(self.class.decompose_codepoints(:canonical, codepoints)))
412:           when :kd
413:             self.class.reorder_characters(self.class.decompose_codepoints(:compatability, codepoints))
414:           when :kc
415:             self.class.compose_codepoints(self.class.reorder_characters(self.class.decompose_codepoints(:compatability, codepoints)))
416:           else
417:             raise ArgumentError, "#{form} is not a valid normalization variant", caller
418:         end.pack('U*'))
419:       end
ord()

Returns the codepoint of the first character in the string.

Example: 

  'こんにちは'.mb_chars.ord #=> 12371

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 369
369:       def ord
370:         self.class.u_unpack(@wrapped_string)[0]
371:       end
respond_to?(method, include_private=false)

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.

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 107
107:       def respond_to?(method, include_private=false)
108:         super || @wrapped_string.respond_to?(method, include_private) || false
109:       end
reverse()

Reverses all characters in the string.

Example: 

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

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 322
322:       def reverse
323:         chars(self.class.g_unpack(@wrapped_string).reverse.flatten.pack('U*'))
324:       end
rindex(needle, offset=nil)

Returns the position needle in the string, counting in codepoints, searching backward from offset or the end of the string. Returns nil if needle isn‘t found.

Example: 

  'Café périferôl'.mb_chars.rindex('é') #=> 6
  'Café périferôl'.mb_chars.rindex(/\w/u) #=> 13

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 211
211:       def rindex(needle, offset=nil)
212:         offset ||= length
213:         wrapped_offset = self.first(offset).wrapped_string.length
214:         index = @wrapped_string.rindex(needle, wrapped_offset)
215:         index ? (self.class.u_unpack(@wrapped_string.slice(0...index)).size) : nil
216:       end
rjust(integer, padstr=' ')

Works just like String#rjust, only integer specifies characters instead of bytes.

Example: 

  "¾ cup".mb_chars.rjust(8).to_s
  #=> "   ¾ cup"

  "¾ cup".mb_chars.rjust(8, " ").to_s # Use non-breaking whitespace
  #=> "   ¾ cup"

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 267
267:       def rjust(integer, padstr=' ')
268:         justify(integer, :right, padstr)
269:       end
rstrip()

Strips entire range of Unicode whitespace from the right of the string.

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 298
298:       def rstrip
299:         chars(@wrapped_string.gsub(UNICODE_TRAILERS_PAT, ''))
300:       end
size()

Returns the number of codepoints in the string

This method is also aliased as length

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 313
313:       def size
314:         self.class.u_unpack(@wrapped_string).size
315:       end
slice(*args)

Implements Unicode-aware slice with codepoints. Slicing on one point returns the codepoints for that character.

Example: 

  'こんにちは'.mb_chars.slice(2..3).to_s #=> "にち"
This method is also aliased as []

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 331
331:       def slice(*args)
332:         if args.size > 2
333:           raise ArgumentError, "wrong number of arguments (#{args.size} for 1)" # Do as if we were native
334:         elsif (args.size == 2 && !(args.first.is_a?(Numeric) || args.first.is_a?(Regexp)))
335:           raise TypeError, "cannot convert #{args.first.class} into Integer" # Do as if we were native
336:         elsif (args.size == 2 && !args[1].is_a?(Numeric))
337:           raise TypeError, "cannot convert #{args[1].class} into Integer" # Do as if we were native
338:         elsif args[0].kind_of? Range
339:           cps = self.class.u_unpack(@wrapped_string).slice(*args)
340:           result = cps.nil? ? nil : cps.pack('U*')
341:         elsif args[0].kind_of? Regexp
342:           result = @wrapped_string.slice(*args)
343:         elsif args.size == 1 && args[0].kind_of?(Numeric)
344:           character = self.class.u_unpack(@wrapped_string)[args[0]]
345:           result = character.nil? ? nil : [character].pack('U')
346:         else
347:           result = self.class.u_unpack(@wrapped_string).slice(*args).pack('U*')
348:         end
349:         result.nil? ? nil : chars(result)
350:       end
slice!(*args)

Like String#slice!, except instead of byte offsets you specify character offsets.

Example: 

  s = 'こんにちは'
  s.mb_chars.slice!(2..3).to_s #=> "にち"
  s #=> "こんは"

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 359
359:       def slice!(*args)
360:         slice = self[*args]
361:         self[*args] = ''
362:         slice
363:       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.

Example: 

  'Café périferôl'.mb_chars.split(/é/).map { |part| part.upcase.to_s } #=> ["CAF", " P", "RIFERÔL"]

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 164
164:       def split(*args)
165:         @wrapped_string.split(*args).map { |i| i.mb_chars }
166:       end
strip()

Strips entire range of Unicode whitespace from the right and left of the string.

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 308
308:       def strip
309:         rstrip.lstrip
310:       end
tidy_bytes()

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

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 449
449:       def tidy_bytes
450:         chars(self.class.tidy_bytes(@wrapped_string))
451:       end
upcase()

Convert characters in the string to uppercase.

Example: 

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

[ show source ]

     # File activesupport/lib/active_support/multibyte/chars.rb, line 377
377:       def upcase
378:         apply_mapping :uppercase_mapping
379:       end