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

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 themb_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

Chars objects are perfectly interchangeable withString objects as long as no explicit class checks are made. If certain methods do explicitly check the class, callto_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

A

C

D

G

I

L

M

N

O

R

S

T

U

W

Included Modules

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: show

def self.consumes?(string)

string.unpack('U*') true rescue ArgumentError false end

new(string)

Creates a new Chars instance by wrapping_string_.

Source: show

def initialize(string) @wrapped_string = string @wrapped_string.force_encoding(Encoding::UTF_8) unless @wrapped_string.frozen? end

wants?(string)

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

Source: show

def self.wants?(string) $KCODE == 'UTF8' && consumes?(string) end

Instance Public methods

+(other)

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

Example:

('Café'.mb_chars + ' périferôl').to_s

Source: show

def +(other) chars(@wrapped_string + other) 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:

'é'.mb_chars <=> 'ü'.mb_chars

See String#<=> for more details.

Source: show

def <=>(other) @wrapped_string <=> other.to_s end

=~(other)

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

Example:

'Café périferôl'.mb_chars =~ /ô/

Source: show

def =(other) translate_offset(@wrapped_string = other) end

[]=(*args)

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

Example:

s = "Müller" s.mb_chars[2] = "e" s

s = "Müller" s.mb_chars[1, 2] = "ö" s

Source: show

def []=(*args) replace_by = args.pop

if args.first.is_a?(Regexp) @wrapped_string[args] = replace_by else result = Unicode.u_unpack(@wrapped_string) case args.first when Fixnum raise IndexError, "index #{args[0]} out of string" if args[0] >= result.length min = args[0] max = args[1].nil? ? min : (min + args[1] - 1) range = Range.new(min, max) replace_by = [replace_by].pack('U') if replace_by.is_a?(Fixnum) when Range raise RangeError, "#{args[0]} out of range" if args[0].min >= result.length range = args[0] else needle = args[0].to_s min = index(needle) max = min + Unicode.u_unpack(needle).length - 1 range = Range.new(min, max) end result[range] = Unicode.u_unpack(replace_by) @wrapped_string.replace(result.pack('U')) end end

acts_like_string?()

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

Source: show

def acts_like_string? true end

capitalize()

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

Example:

'über'.mb_chars.capitalize.to_s

Source: show

def capitalize (slice(0) || chars('')).upcase + (slice(1..-1) || chars('')).downcase 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".mb_chars.center(8, " ").to_s

Source: show

def center(integer, padstr=' ') justify(integer, :center, padstr) end

compose()

Performs composition on all the characters.

Example:

'é'.length
'é'.mb_chars.compose.to_s.length

Source: show

def compose chars(Unicode.compose_codepoints(Unicode.u_unpack(@wrapped_string)).pack('U*')) end

decompose()

Performs canonical decomposition on all the characters.

Example:

'é'.length
'é'.mb_chars.decompose.to_s.length

Source: show

def decompose chars(Unicode.decompose_codepoints(:canonical, Unicode.u_unpack(@wrapped_string)).pack('U*')) end

downcase()

Convert characters in the string to lowercase.

Example:

'VĚDA A VÝZKUM'.mb_chars.downcase.to_s

Source: show

def downcase chars(Unicode.apply_mapping @wrapped_string, :lowercase_mapping) end

g_length()

Returns the number of grapheme clusters in the string.

Example:

'क्षि'.mb_chars.length
'क्षि'.mb_chars.g_length

Source: show

def g_length Unicode.g_unpack(@wrapped_string).length end

include?(other)

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

Example:

'Café'.mb_chars.include?('é')

Source: show

def include?(other)

@wrapped_string.include?(other) 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')
'Café périferôl'.mb_chars.index(/\w/)

Source: show

def index(needle, offset=0) wrapped_offset = first(offset).wrapped_string.length index = @wrapped_string.index(needle, wrapped_offset) index ? (Unicode.u_unpack(@wrapped_string.slice(0...index)).size) : nil end

insert(offset, fragment)

Inserts the passed string at specified codepoint offsets.

Example:

'Café'.mb_chars.insert(4, ' périferôl').to_s

Source: show

def insert(offset, fragment) unpacked = Unicode.u_unpack(@wrapped_string) unless offset > unpacked.length @wrapped_string.replace( Unicode.u_unpack(@wrapped_string).insert(offset, Unicode.u_unpack(fragment)).pack('U') ) else raise IndexError, "index #{offset} out of string" end self end

limit(limit)

Limit 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.

Example:

'こんにちは'.mb_chars.limit(7).to_s

Source: show

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

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".mb_chars.rjust(8, " ").to_s

Source: show

def ljust(integer, padstr=' ') justify(integer, :left, padstr) end

lstrip()

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

Source: show

def lstrip chars(@wrapped_string.gsub(Unicode::LEADERS_PAT, '')) end

method_missing(method, *args, &block)

Forward all undefined methods to the wrapped string.

Source: show

def method_missing(method, *args, &block) if method.to_s =~ /!$/ @wrapped_string.send(method, *args, &block) self else result = @wrapped_string.send(method, *args, &block) result.kind_of?(String) ? chars(result) : result end 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.

Source: show

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

ord()

Returns the codepoint of the first character in the string.

Example:

'こんにちは'.mb_chars.ord

Source: show

def ord Unicode.u_unpack(@wrapped_string)[0] 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.

Source: show

def respond_to?(method, include_private=false) super || @wrapped_string.respond_to?(method, include_private) end

reverse()

Reverses all characters in the string.

Example:

'Café'.mb_chars.reverse.to_s

Source: show

def reverse chars(Unicode.g_unpack(@wrapped_string).reverse.flatten.pack('U*')) 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. Returnsnil if needle isn’t found.

Example:

'Café périferôl'.mb_chars.rindex('é')
'Café périferôl'.mb_chars.rindex(/\w/)

Source: show

def rindex(needle, offset=nil) offset ||= length wrapped_offset = first(offset).wrapped_string.length index = @wrapped_string.rindex(needle, wrapped_offset) index ? (Unicode.u_unpack(@wrapped_string.slice(0...index)).size) : nil 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".mb_chars.rjust(8, " ").to_s

Source: show

def rjust(integer, padstr=' ') justify(integer, :right, padstr) end

rstrip()

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

Source: show

def rstrip chars(@wrapped_string.gsub(Unicode::TRAILERS_PAT, '')) end

size()

Returns the number of codepoints in the string

Source: show

def size Unicode.u_unpack(@wrapped_string).size 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

Also aliased as: []

Source: show

def slice(*args) if args.size > 2 raise ArgumentError, "wrong number of arguments (#{args.size} for 1)" elsif (args.size == 2 && !(args.first.is_a?(Numeric) || args.first.is_a?(Regexp))) raise TypeError, "cannot convert #{args.first.class} into Integer" elsif (args.size == 2 && !args[1].is_a?(Numeric)) raise TypeError, "cannot convert #{args[1].class} into Integer" elsif args[0].kind_of? Range cps = Unicode.u_unpack(@wrapped_string).slice(args) result = cps.nil? ? nil : cps.pack('U') elsif args[0].kind_of? Regexp result = @wrapped_string.slice(*args) elsif args.size == 1 && args[0].kind_of?(Numeric) character = Unicode.u_unpack(@wrapped_string)[args[0]] result = character && [character].pack('U') else cps = Unicode.u_unpack(@wrapped_string).slice(args) result = cps && cps.pack('U') end result && chars(result) 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 }

Source: show

def split(*args) @wrapped_string.split(*args).map { |i| i.mb_chars } end

strip()

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

Source: show

def strip rstrip.lstrip 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.

Source: show

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

titleize()

Capitalizes the first letter of every word, when possible.

Example:

"ÉL QUE SE ENTERÓ".mb_chars.titleize
"日本語".mb_chars.titleize

Source: show

def titleize chars(downcase.to_s.gsub(/\b('?[\S])/) { Unicode.apply_mapping $1, :uppercase_mapping }) end

upcase()

Convert characters in the string to uppercase.

Example:

'Laurent, où sont les tests ?'.mb_chars.upcase.to_s

Source: show

def upcase chars(Unicode.apply_mapping @wrapped_string, :uppercase_mapping) end