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Diffstat (limited to 'intl/locale/PluralForm.sys.mjs')
| -rw-r--r-- | intl/locale/PluralForm.sys.mjs | 311 |
1 files changed, 311 insertions, 0 deletions
diff --git a/intl/locale/PluralForm.sys.mjs b/intl/locale/PluralForm.sys.mjs new file mode 100644 index 0000000000..cd7f920aaa --- /dev/null +++ b/intl/locale/PluralForm.sys.mjs @@ -0,0 +1,311 @@ +/* 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 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. +/* eslint-disable no-nested-ternary */ +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), + ], + // 19: Slavic languages (bs, hr, sr). Same as rule 7, but resulting in different CLDR categories + [ + 3, + n => + n % 10 == 1 && n % 100 != 11 + ? 0 + : n % 10 >= 2 && n % 10 <= 4 && (n % 100 < 10 || n % 100 >= 20) + ? 1 + : 2, + ], +]; + +/* eslint-enable no-nested-ternary */ + +export 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(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( + Services.strings + .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); + Services.console.logStringMessage(msg); + dump(msg + "\n"); +} |