michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: this.EXPORTED_SYMBOLS = [ "PluralForm" ];
michael@0: 
michael@0: /**
michael@0:  * This module provides the PluralForm object which contains a method to figure
michael@0:  * out which plural form of a word to use for a given number based on the
michael@0:  * current localization. There is also a makeGetter method that creates a get
michael@0:  * function for the desired plural rule. This is useful for extensions that
michael@0:  * specify their own plural rule instead of relying on the browser default.
michael@0:  * (I.e., the extension hasn't been localized to the browser's locale.)
michael@0:  *
michael@0:  * See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
michael@0:  *
michael@0:  * List of methods:
michael@0:  *
michael@0:  * string pluralForm
michael@0:  * get(int aNum, string aWords)
michael@0:  *
michael@0:  * int numForms
michael@0:  * numForms()
michael@0:  *
michael@0:  * [string pluralForm get(int aNum, string aWords), int numForms numForms()]
michael@0:  * makeGetter(int aRuleNum)
michael@0:  * Note: Basically, makeGetter returns 2 functions that do "get" and "numForm"
michael@0:  */
michael@0: 
michael@0: const Cc = Components.classes;
michael@0: const Ci = Components.interfaces;
michael@0: 
michael@0: const kIntlProperties = "chrome://global/locale/intl.properties";
michael@0: 
michael@0: // These are the available plural functions that give the appropriate index
michael@0: // based on the plural rule number specified. The first element is the number
michael@0: // of plural forms and the second is the function to figure out the index.
michael@0: let gFunctions = [
michael@0:   // 0: Chinese
michael@0:   [1, function(n) 0],
michael@0:   // 1: English
michael@0:   [2, function(n) n!=1?1:0],
michael@0:   // 2: French
michael@0:   [2, function(n) n>1?1:0],
michael@0:   // 3: Latvian
michael@0:   [3, function(n) n%10==1&&n%100!=11?1:n!=0?2:0],
michael@0:   // 4: Scottish Gaelic
michael@0:   [4, function(n) n==1||n==11?0:n==2||n==12?1:n>0&&n<20?2:3],
michael@0:   // 5: Romanian
michael@0:   [3, function(n) n==1?0:n==0||n%100>0&&n%100<20?1:2],
michael@0:   // 6: Lithuanian
michael@0:   [3, function(n) n%10==1&&n%100!=11?0:n%10>=2&&(n%100<10||n%100>=20)?2:1],
michael@0:   // 7: Russian
michael@0:   [3, function(n) n%10==1&&n%100!=11?0:n%10>=2&&n%10<=4&&(n%100<10||n%100>=20)?1:2],
michael@0:   // 8: Slovak
michael@0:   [3, function(n) n==1?0:n>=2&&n<=4?1:2],
michael@0:   // 9: Polish
michael@0:   [3, function(n) n==1?0:n%10>=2&&n%10<=4&&(n%100<10||n%100>=20)?1:2],
michael@0:   // 10: Slovenian
michael@0:   [4, function(n) n%100==1?0:n%100==2?1:n%100==3||n%100==4?2:3],
michael@0:   // 11: Irish Gaeilge
michael@0:   [5, function(n) n==1?0:n==2?1:n>=3&&n<=6?2:n>=7&&n<=10?3:4],
michael@0:   // 12: Arabic
michael@0:   [6, function(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],
michael@0:   // 13: Maltese
michael@0:   [4, function(n) n==1?0:n==0||n%100>0&&n%100<=10?1:n%100>10&&n%100<20?2:3],
michael@0:   // 14: Macedonian
michael@0:   [3, function(n) n%10==1?0:n%10==2?1:2],
michael@0:   // 15: Icelandic
michael@0:   [2, function(n) n%10==1&&n%100!=11?0:1],
michael@0:   // 16: Breton
michael@0:   [5, function(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],
michael@0: ];
michael@0: 
michael@0: this.PluralForm = {
michael@0:   /**
michael@0:    * Get the correct plural form of a word based on the number
michael@0:    *
michael@0:    * @param aNum
michael@0:    *        The number to decide which plural form to use
michael@0:    * @param aWords
michael@0:    *        A semi-colon (;) separated string of words to pick the plural form
michael@0:    * @return The appropriate plural form of the word
michael@0:    */
michael@0:   get get()
michael@0:   {
michael@0:     // This method will lazily load to avoid perf when it is first needed and
michael@0:     // creates getPluralForm function. The function it creates is based on the
michael@0:     // value of pluralRule specified in the intl stringbundle.
michael@0:     // See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
michael@0: 
michael@0:     // Delete the getters to be overwritten
michael@0:     delete PluralForm.numForms;
michael@0:     delete PluralForm.get;
michael@0: 
michael@0:     // Get the plural rule number from the intl stringbundle
michael@0:     let ruleNum = Number(Cc["@mozilla.org/intl/stringbundle;1"].
michael@0:       getService(Ci.nsIStringBundleService).createBundle(kIntlProperties).
michael@0:       GetStringFromName("pluralRule"));
michael@0: 
michael@0:     // Make the plural form get function and set it as the default get
michael@0:     [PluralForm.get, PluralForm.numForms] = PluralForm.makeGetter(ruleNum);
michael@0:     return PluralForm.get;
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Create a pair of plural form functions for the given plural rule number.
michael@0:    *
michael@0:    * @param aRuleNum
michael@0:    *        The plural rule number to create functions
michael@0:    * @return A pair: [function that gets the right plural form,
michael@0:    *                  function that returns the number of plural forms]
michael@0:    */
michael@0:   makeGetter: function(aRuleNum)
michael@0:   {
michael@0:     // Default to "all plural" if the value is out of bounds or invalid
michael@0:     if (aRuleNum < 0 || aRuleNum >= gFunctions.length || isNaN(aRuleNum)) {
michael@0:       log(["Invalid rule number: ", aRuleNum, " -- defaulting to 0"]);
michael@0:       aRuleNum = 0;
michael@0:     }
michael@0: 
michael@0:     // Get the desired pluralRule function
michael@0:     let [numForms, pluralFunc] = gFunctions[aRuleNum];
michael@0: 
michael@0:     // Return functions that give 1) the number of forms and 2) gets the right
michael@0:     // plural form
michael@0:     return [function(aNum, aWords) {
michael@0:       // Figure out which index to use for the semi-colon separated words
michael@0:       let index = pluralFunc(aNum ? Number(aNum) : 0);
michael@0:       let words = aWords ? aWords.split(/;/) : [""];
michael@0: 
michael@0:       // Explicitly check bounds to avoid strict warnings
michael@0:       let ret = index < words.length ? words[index] : undefined;
michael@0: 
michael@0:       // Check for array out of bounds or empty strings
michael@0:       if ((ret == undefined) || (ret == "")) {
michael@0:         // Report the caller to help figure out who is causing badness
michael@0:         let caller = PluralForm.get.caller ? PluralForm.get.caller.name : "top";
michael@0: 
michael@0:         // Display a message in the error console
michael@0:         log(["Index #", index, " of '", aWords, "' for value ", aNum,
michael@0:             " is invalid -- plural rule #", aRuleNum, "; called by ", caller]);
michael@0: 
michael@0:         // Default to the first entry (which might be empty, but not undefined)
michael@0:         ret = words[0];
michael@0:       }
michael@0: 
michael@0:       return ret;
michael@0:     }, function() numForms];
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Get the number of forms for the current plural rule
michael@0:    *
michael@0:    * @return The number of forms
michael@0:    */
michael@0:   get numForms()
michael@0:   {
michael@0:     // We lazily load numForms, so trigger the init logic with get()
michael@0:     PluralForm.get();
michael@0:     return PluralForm.numForms;
michael@0:   },
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * Private helper function to log errors to the error console and command line
michael@0:  *
michael@0:  * @param aMsg
michael@0:  *        Error message to log or an array of strings to concat
michael@0:  */
michael@0: function log(aMsg)
michael@0: {
michael@0:   let msg = "PluralForm.jsm: " + (aMsg.join ? aMsg.join("") : aMsg);
michael@0:   Cc["@mozilla.org/consoleservice;1"].getService(Ci.nsIConsoleService).
michael@0:     logStringMessage(msg);
michael@0:   dump(msg + "\n");
michael@0: }