gecko-dev/intl/locale/PluralForm.jsm

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/* 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/. */
var 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
*
* NOTE: any change to these plural forms need to be reflected in
* compare-locales:
* https://hg.mozilla.org/l10n/compare-locales/file/default/compare_locales/plurals.py
*
* 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 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%10==0?0:2],
// 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: Unused
[3, (n) => n%10==1?0:n%10==2?1:2],
// 15: Icelandic, Macedonian
[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],
// 17: Shuar
[2, (n) => n!=0?1:0],
// 18: Welsh
[6, (n) => n==0?0:n==1?1:n==2?2:n==3?3:n==6?4:5],
];
var 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");
}