aboutsummaryrefslogtreecommitdiffstats
path: root/activesupport/lib/active_support/inflector/methods.rb
blob: ef3df1240dda825ea840897983d0b5f10d6a8c99 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
require "active_support/inflections"
require "active_support/core_ext/regexp"

module ActiveSupport
  # The Inflector transforms words from singular to plural, class names to table
  # names, modularized class names to ones without, and class names to foreign
  # keys. The default inflections for pluralization, singularization, and
  # uncountable words are kept in inflections.rb.
  #
  # The Rails core team has stated patches for the inflections library will not
  # be accepted in order to avoid breaking legacy applications which may be
  # relying on errant inflections. If you discover an incorrect inflection and
  # require it for your application or wish to define rules for languages other
  # than English, please correct or add them yourself (explained below).
  module Inflector
    extend self

    # Returns the plural form of the word in the string.
    #
    # If passed an optional +locale+ parameter, the word will be
    # pluralized using rules defined for that language. By default,
    # this parameter is set to <tt>:en</tt>.
    #
    #   pluralize('post')             # => "posts"
    #   pluralize('octopus')          # => "octopi"
    #   pluralize('sheep')            # => "sheep"
    #   pluralize('words')            # => "words"
    #   pluralize('CamelOctopus')     # => "CamelOctopi"
    #   pluralize('ley', :es)         # => "leyes"
    def pluralize(word, locale = :en)
      apply_inflections(word, inflections(locale).plurals)
    end

    # The reverse of #pluralize, returns the singular form of a word in a
    # string.
    #
    # If passed an optional +locale+ parameter, the word will be
    # singularized using rules defined for that language. By default,
    # this parameter is set to <tt>:en</tt>.
    #
    #   singularize('posts')            # => "post"
    #   singularize('octopi')           # => "octopus"
    #   singularize('sheep')            # => "sheep"
    #   singularize('word')             # => "word"
    #   singularize('CamelOctopi')      # => "CamelOctopus"
    #   singularize('leyes', :es)       # => "ley"
    def singularize(word, locale = :en)
      apply_inflections(word, inflections(locale).singulars)
    end

    # Converts strings to UpperCamelCase.
    # If the +uppercase_first_letter+ parameter is set to false, then produces
    # lowerCamelCase.
    #
    # Also converts '/' to '::' which is useful for converting
    # paths to namespaces.
    #
    #   camelize('active_model')                # => "ActiveModel"
    #   camelize('active_model', false)         # => "activeModel"
    #   camelize('active_model/errors')         # => "ActiveModel::Errors"
    #   camelize('active_model/errors', false)  # => "activeModel::Errors"
    #
    # As a rule of thumb you can think of +camelize+ as the inverse of
    # #underscore, though there are cases where that does not hold:
    #
    #   camelize(underscore('SSLError'))        # => "SslError"
    def camelize(term, uppercase_first_letter = true)
      string = term.to_s
      if uppercase_first_letter
        string = string.sub(/^[a-z\d]*/) { |match| inflections.acronyms[match] || match.capitalize }
      else
        string = string.sub(/^(?:#{inflections.acronym_regex}(?=\b|[A-Z_])|\w)/) { |match| match.downcase }
      end
      string.gsub!(/(?:_|(\/))([a-z\d]*)/i) { "#{$1}#{inflections.acronyms[$2] || $2.capitalize}" }
      string.gsub!("/".freeze, "::".freeze)
      string
    end

    # Makes an underscored, lowercase form from the expression in the string.
    #
    # Changes '::' to '/' to convert namespaces to paths.
    #
    #   underscore('ActiveModel')         # => "active_model"
    #   underscore('ActiveModel::Errors') # => "active_model/errors"
    #
    # As a rule of thumb you can think of +underscore+ as the inverse of
    # #camelize, though there are cases where that does not hold:
    #
    #   camelize(underscore('SSLError'))  # => "SslError"
    def underscore(camel_cased_word)
      return camel_cased_word unless /[A-Z-]|::/.match?(camel_cased_word)
      word = camel_cased_word.to_s.gsub("::".freeze, "/".freeze)
      word.gsub!(/(?:(?<=([A-Za-z\d]))|\b)(#{inflections.acronym_regex})(?=\b|[^a-z])/) { "#{$1 && '_'.freeze }#{$2.downcase}" }
      word.gsub!(/([A-Z\d]+)([A-Z][a-z])/, '\1_\2'.freeze)
      word.gsub!(/([a-z\d])([A-Z])/, '\1_\2'.freeze)
      word.tr!("-".freeze, "_".freeze)
      word.downcase!
      word
    end

    # Tweaks an attribute name for display to end users.
    #
    # Specifically, performs these transformations:
    #
    # * Applies human inflection rules to the argument.
    # * Deletes leading underscores, if any.
    # * Removes a "_id" suffix if present.
    # * Replaces underscores with spaces, if any.
    # * Downcases all words except acronyms.
    # * Capitalizes the first word.
    #
    # The capitalization of the first word can be turned off by setting the
    # +:capitalize+ option to false (default is true).
    #
    #   humanize('employee_salary')              # => "Employee salary"
    #   humanize('author_id')                    # => "Author"
    #   humanize('author_id', capitalize: false) # => "author"
    #   humanize('_id')                          # => "Id"
    #
    # If "SSL" was defined to be an acronym:
    #
    #   humanize('ssl_error') # => "SSL error"
    #
    def humanize(lower_case_and_underscored_word, options = {})
      result = lower_case_and_underscored_word.to_s.dup

      inflections.humans.each { |(rule, replacement)| break if result.sub!(rule, replacement) }

      result.sub!(/\A_+/, "".freeze)
      result.sub!(/_id\z/, "".freeze)
      result.tr!("_".freeze, " ".freeze)

      result.gsub!(/([a-z\d]*)/i) do |match|
        "#{inflections.acronyms[match] || match.downcase}"
      end

      if options.fetch(:capitalize, true)
        result.sub!(/\A\w/) { |match| match.upcase }
      end

      result
    end

    # Converts just the first character to uppercase.
    #
    #   upcase_first('what a Lovely Day') # => "What a Lovely Day"
    #   upcase_first('w')                 # => "W"
    #   upcase_first('')                  # => ""
    def upcase_first(string)
      string.length > 0 ? string[0].upcase.concat(string[1..-1]) : ""
    end

    # Capitalizes all the words and replaces some characters in the string to
    # create a nicer looking title. +titleize+ is meant for creating pretty
    # output. It is not used in the Rails internals.
    #
    # +titleize+ is also aliased as +titlecase+.
    #
    #   titleize('man from the boondocks')   # => "Man From The Boondocks"
    #   titleize('x-men: the last stand')    # => "X Men: The Last Stand"
    #   titleize('TheManWithoutAPast')       # => "The Man Without A Past"
    #   titleize('raiders_of_the_lost_ark')  # => "Raiders Of The Lost Ark"
    def titleize(word)
      humanize(underscore(word)).gsub(/\b(?<!['’`])[a-z]/) { |match| match.capitalize }
    end

    # Creates the name of a table like Rails does for models to table names.
    # This method uses the #pluralize method on the last word in the string.
    #
    #   tableize('RawScaledScorer') # => "raw_scaled_scorers"
    #   tableize('ham_and_egg')     # => "ham_and_eggs"
    #   tableize('fancyCategory')   # => "fancy_categories"
    def tableize(class_name)
      pluralize(underscore(class_name))
    end

    # Creates a class name from a plural table name like Rails does for table
    # names to models. Note that this returns a string and not a Class (To
    # convert to an actual class follow +classify+ with #constantize).
    #
    #   classify('ham_and_eggs') # => "HamAndEgg"
    #   classify('posts')        # => "Post"
    #
    # Singular names are not handled correctly:
    #
    #   classify('calculus')     # => "Calculus"
    def classify(table_name)
      # strip out any leading schema name
      camelize(singularize(table_name.to_s.sub(/.*\./, "".freeze)))
    end

    # Replaces underscores with dashes in the string.
    #
    #   dasherize('puni_puni') # => "puni-puni"
    def dasherize(underscored_word)
      underscored_word.tr("_".freeze, "-".freeze)
    end

    # Removes the module part from the expression in the string.
    #
    #   demodulize('ActiveRecord::CoreExtensions::String::Inflections') # => "Inflections"
    #   demodulize('Inflections')                                       # => "Inflections"
    #   demodulize('::Inflections')                                     # => "Inflections"
    #   demodulize('')                                                  # => ""
    #
    # See also #deconstantize.
    def demodulize(path)
      path = path.to_s
      if i = path.rindex("::")
        path[(i + 2)..-1]
      else
        path
      end
    end

    # Removes the rightmost segment from the constant expression in the string.
    #
    #   deconstantize('Net::HTTP')   # => "Net"
    #   deconstantize('::Net::HTTP') # => "::Net"
    #   deconstantize('String')      # => ""
    #   deconstantize('::String')    # => ""
    #   deconstantize('')            # => ""
    #
    # See also #demodulize.
    def deconstantize(path)
      path.to_s[0, path.rindex("::") || 0] # implementation based on the one in facets' Module#spacename
    end

    # Creates a foreign key name from a class name.
    # +separate_class_name_and_id_with_underscore+ sets whether
    # the method should put '_' between the name and 'id'.
    #
    #   foreign_key('Message')        # => "message_id"
    #   foreign_key('Message', false) # => "messageid"
    #   foreign_key('Admin::Post')    # => "post_id"
    def foreign_key(class_name, separate_class_name_and_id_with_underscore = true)
      underscore(demodulize(class_name)) + (separate_class_name_and_id_with_underscore ? "_id" : "id")
    end

    # Tries to find a constant with the name specified in the argument string.
    #
    #   constantize('Module')   # => Module
    #   constantize('Foo::Bar') # => Foo::Bar
    #
    # The name is assumed to be the one of a top-level constant, no matter
    # whether it starts with "::" or not. No lexical context is taken into
    # account:
    #
    #   C = 'outside'
    #   module M
    #     C = 'inside'
    #     C                # => 'inside'
    #     constantize('C') # => 'outside', same as ::C
    #   end
    #
    # NameError is raised when the name is not in CamelCase or the constant is
    # unknown.
    def constantize(camel_cased_word)
      names = camel_cased_word.split("::".freeze)

      # Trigger a built-in NameError exception including the ill-formed constant in the message.
      Object.const_get(camel_cased_word) if names.empty?

      # Remove the first blank element in case of '::ClassName' notation.
      names.shift if names.size > 1 && names.first.empty?

      names.inject(Object) do |constant, name|
        if constant == Object
          constant.const_get(name)
        else
          candidate = constant.const_get(name)
          next candidate if constant.const_defined?(name, false)
          next candidate unless Object.const_defined?(name)

          # Go down the ancestors to check if it is owned directly. The check
          # stops when we reach Object or the end of ancestors tree.
          constant = constant.ancestors.inject do |const, ancestor|
            break const    if ancestor == Object
            break ancestor if ancestor.const_defined?(name, false)
            const
          end

          # owner is in Object, so raise
          constant.const_get(name, false)
        end
      end
    end

    # Tries to find a constant with the name specified in the argument string.
    #
    #   safe_constantize('Module')   # => Module
    #   safe_constantize('Foo::Bar') # => Foo::Bar
    #
    # The name is assumed to be the one of a top-level constant, no matter
    # whether it starts with "::" or not. No lexical context is taken into
    # account:
    #
    #   C = 'outside'
    #   module M
    #     C = 'inside'
    #     C                     # => 'inside'
    #     safe_constantize('C') # => 'outside', same as ::C
    #   end
    #
    # +nil+ is returned when the name is not in CamelCase or the constant (or
    # part of it) is unknown.
    #
    #   safe_constantize('blargle')                  # => nil
    #   safe_constantize('UnknownModule')            # => nil
    #   safe_constantize('UnknownModule::Foo::Bar')  # => nil
    def safe_constantize(camel_cased_word)
      constantize(camel_cased_word)
    rescue NameError => e
      raise if e.name && !(camel_cased_word.to_s.split("::").include?(e.name.to_s) ||
        e.name.to_s == camel_cased_word.to_s)
    rescue ArgumentError => e
      raise unless /not missing constant #{const_regexp(camel_cased_word)}!$/.match?(e.message)
    end

    # Returns the suffix that should be added to a number to denote the position
    # in an ordered sequence such as 1st, 2nd, 3rd, 4th.
    #
    #   ordinal(1)     # => "st"
    #   ordinal(2)     # => "nd"
    #   ordinal(1002)  # => "nd"
    #   ordinal(1003)  # => "rd"
    #   ordinal(-11)   # => "th"
    #   ordinal(-1021) # => "st"
    def ordinal(number)
      abs_number = number.to_i.abs

      if (11..13).include?(abs_number % 100)
        "th"
      else
        case abs_number % 10
        when 1; "st"
        when 2; "nd"
        when 3; "rd"
          else    "th"
        end
      end
    end

    # Turns a number into an ordinal string used to denote the position in an
    # ordered sequence such as 1st, 2nd, 3rd, 4th.
    #
    #   ordinalize(1)     # => "1st"
    #   ordinalize(2)     # => "2nd"
    #   ordinalize(1002)  # => "1002nd"
    #   ordinalize(1003)  # => "1003rd"
    #   ordinalize(-11)   # => "-11th"
    #   ordinalize(-1021) # => "-1021st"
    def ordinalize(number)
      "#{number}#{ordinal(number)}"
    end

    private

      # Mounts a regular expression, returned as a string to ease interpolation,
      # that will match part by part the given constant.
      #
      #   const_regexp("Foo::Bar::Baz") # => "Foo(::Bar(::Baz)?)?"
      #   const_regexp("::")            # => "::"
      def const_regexp(camel_cased_word) #:nodoc:
        parts = camel_cased_word.split("::".freeze)

        return Regexp.escape(camel_cased_word) if parts.blank?

        last = parts.pop

        parts.reverse.inject(last) do |acc, part|
          part.empty? ? acc : "#{part}(::#{acc})?"
        end
      end

      # Applies inflection rules for +singularize+ and +pluralize+.
      #
      #  apply_inflections('post', inflections.plurals)    # => "posts"
      #  apply_inflections('posts', inflections.singulars) # => "post"
      def apply_inflections(word, rules)
        result = word.to_s.dup

        if word.empty? || inflections.uncountables.uncountable?(result)
          result
        else
          rules.each { |(rule, replacement)| break if result.sub!(rule, replacement) }
          result
        end
      end
  end
end