summaryrefslogtreecommitdiffstats
path: root/intl/locale/PluralForm.jsm
blob: 9f249fce56db5274744a338c1d4b9993c051c919 (plain)
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
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

this.EXPORTED_SYMBOLS = [ "PluralForm" ];

/**
 * This module provides the PluralForm object which contains a method to figure
 * out which plural form of a word to use for a given number based on the
 * current localization. There is also a makeGetter method that creates a get
 * function for the desired plural rule. This is useful for extensions that
 * specify their own plural rule instead of relying on the browser default.
 * (I.e., the extension hasn't been localized to the browser's locale.)
 *
 * See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
 *
 * List of methods:
 *
 * string pluralForm
 * get(int aNum, string aWords)
 *
 * int numForms
 * numForms()
 *
 * [string pluralForm get(int aNum, string aWords), int numForms numForms()]
 * makeGetter(int aRuleNum)
 * Note: Basically, makeGetter returns 2 functions that do "get" and "numForm"
 */

const Cc = Components.classes;
const Ci = Components.interfaces;

const kIntlProperties = "chrome://global/locale/intl.properties";

// These are the available plural functions that give the appropriate index
// based on the plural rule number specified. The first element is the number
// of plural forms and the second is the function to figure out the index.
var gFunctions = [
  // 0: Chinese
  [1, (n) => 0],
  // 1: English
  [2, (n) => n!=1?1:0],
  // 2: French
  [2, (n) => n>1?1:0],
  // 3: Latvian
  [3, (n) => n%10==1&&n%100!=11?1:n!=0?2:0],
  // 4: Scottish Gaelic
  [4, (n) => n==1||n==11?0:n==2||n==12?1:n>0&&n<20?2:3],
  // 5: Romanian
  [3, (n) => n==1?0:n==0||n%100>0&&n%100<20?1:2],
  // 6: Lithuanian
  [3, (n) => n%10==1&&n%100!=11?0:n%10>=2&&(n%100<10||n%100>=20)?2:1],
  // 7: Russian
  [3, (n) => n%10==1&&n%100!=11?0:n%10>=2&&n%10<=4&&(n%100<10||n%100>=20)?1:2],
  // 8: Slovak
  [3, (n) => n==1?0:n>=2&&n<=4?1:2],
  // 9: Polish
  [3, (n) => n==1?0:n%10>=2&&n%10<=4&&(n%100<10||n%100>=20)?1:2],
  // 10: Slovenian
  [4, (n) => n%100==1?0:n%100==2?1:n%100==3||n%100==4?2:3],
  // 11: Irish Gaeilge
  [5, (n) => n==1?0:n==2?1:n>=3&&n<=6?2:n>=7&&n<=10?3:4],
  // 12: Arabic
  [6, (n) => n==0?5:n==1?0:n==2?1:n%100>=3&&n%100<=10?2:n%100>=11&&n%100<=99?3:4],
  // 13: Maltese
  [4, (n) => n==1?0:n==0||n%100>0&&n%100<=10?1:n%100>10&&n%100<20?2:3],
  // 14: Macedonian
  [3, (n) => n%10==1?0:n%10==2?1:2],
  // 15: Icelandic
  [2, (n) => n%10==1&&n%100!=11?0:1],
  // 16: Breton
  [5, (n) => n%10==1&&n%100!=11&&n%100!=71&&n%100!=91?0:n%10==2&&n%100!=12&&n%100!=72&&n%100!=92?1:(n%10==3||n%10==4||n%10==9)&&n%100!=13&&n%100!=14&&n%100!=19&&n%100!=73&&n%100!=74&&n%100!=79&&n%100!=93&&n%100!=94&&n%100!=99?2:n%1000000==0&&n!=0?3:4],
];

this.PluralForm = {
  /**
   * Get the correct plural form of a word based on the number
   *
   * @param aNum
   *        The number to decide which plural form to use
   * @param aWords
   *        A semi-colon (;) separated string of words to pick the plural form
   * @return The appropriate plural form of the word
   */
  get get()
  {
    // This method will lazily load to avoid perf when it is first needed and
    // creates getPluralForm function. The function it creates is based on the
    // value of pluralRule specified in the intl stringbundle.
    // See: http://developer.mozilla.org/en/docs/Localization_and_Plurals

    // Delete the getters to be overwritten
    delete PluralForm.numForms;
    delete PluralForm.get;

    // Make the plural form get function and set it as the default get
    [PluralForm.get, PluralForm.numForms] = PluralForm.makeGetter(PluralForm.ruleNum);
    return PluralForm.get;
  },

  /**
   * Create a pair of plural form functions for the given plural rule number.
   *
   * @param aRuleNum
   *        The plural rule number to create functions
   * @return A pair: [function that gets the right plural form,
   *                  function that returns the number of plural forms]
   */
  makeGetter: function(aRuleNum)
  {
    // Default to "all plural" if the value is out of bounds or invalid
    if (aRuleNum < 0 || aRuleNum >= gFunctions.length || isNaN(aRuleNum)) {
      log(["Invalid rule number: ", aRuleNum, " -- defaulting to 0"]);
      aRuleNum = 0;
    }

    // Get the desired pluralRule function
    let [numForms, pluralFunc] = gFunctions[aRuleNum];

    // Return functions that give 1) the number of forms and 2) gets the right
    // plural form
    return [function(aNum, aWords) {
      // Figure out which index to use for the semi-colon separated words
      let index = pluralFunc(aNum ? Number(aNum) : 0);
      let words = aWords ? aWords.split(/;/) : [""];

      // Explicitly check bounds to avoid strict warnings
      let ret = index < words.length ? words[index] : undefined;

      // Check for array out of bounds or empty strings
      if ((ret == undefined) || (ret == "")) {
        // Report the caller to help figure out who is causing badness
        let caller = Components.stack.caller ? Components.stack.caller.name : "top";

        // Display a message in the error console
        log(["Index #", index, " of '", aWords, "' for value ", aNum,
            " is invalid -- plural rule #", aRuleNum, "; called by ", caller]);

        // Default to the first entry (which might be empty, but not undefined)
        ret = words[0];
      }

      return ret;
    }, () => numForms];
  },

  /**
   * Get the number of forms for the current plural rule
   *
   * @return The number of forms
   */
  get numForms()
  {
    // We lazily load numForms, so trigger the init logic with get()
    PluralForm.get();
    return PluralForm.numForms;
  },

  /**
   * Get the plural rule number from the intl stringbundle
   *
   * @return The plural rule number
   */
  get ruleNum()
  {
    return Number(Cc["@mozilla.org/intl/stringbundle;1"].
      getService(Ci.nsIStringBundleService).createBundle(kIntlProperties).
      GetStringFromName("pluralRule"));
  }
};

/**
 * Private helper function to log errors to the error console and command line
 *
 * @param aMsg
 *        Error message to log or an array of strings to concat
 */
function log(aMsg)
{
  let msg = "PluralForm.jsm: " + (aMsg.join ? aMsg.join("") : aMsg);
  Cc["@mozilla.org/consoleservice;1"].getService(Ci.nsIConsoleService).
    logStringMessage(msg);
  dump(msg + "\n");
}