resources/lib/CLDRPluralRuleParser/CLDRPluralRuleParser.js
/**
* cldrpluralparser.js
* A parser engine for CLDR plural rules.
*
* Copyright 2012-2014 Santhosh Thottingal and other contributors
* Released under the MIT license
* http://opensource.org/licenses/MIT
*
* @source https://github.com/santhoshtr/CLDRPluralRuleParser
* @author Santhosh Thottingal <santhosh.thottingal@gmail.com>
* @author Timo Tijhof
* @author Amir Aharoni
*/
/**
* Evaluates a plural rule in CLDR syntax for a number
* @param {string} rule
* @param {integer} number
* @return {boolean} true if evaluation passed, false if evaluation failed.
*/
// UMD returnExports https://github.com/umdjs/umd/blob/master/returnExports.js
(function(root, factory) {
if (typeof define === 'function' && define.amd) {
// AMD. Register as an anonymous module.
define(factory);
} else if (typeof exports === 'object') {
/* global module */
// Node. Does not work with strict CommonJS, but
// only CommonJS-like environments that support module.exports,
// like Node.
module.exports = factory();
} else {
// Browser globals (root is window)
root.pluralRuleParser = factory();
}
}(this, function() {
function pluralRuleParser(rule, number) {
'use strict';
/*
Syntax: see http://unicode.org/reports/tr35/#Language_Plural_Rules
-----------------------------------------------------------------
condition = and_condition ('or' and_condition)*
('@integer' samples)?
('@decimal' samples)?
and_condition = relation ('and' relation)*
relation = is_relation | in_relation | within_relation
is_relation = expr 'is' ('not')? value
in_relation = expr (('not')? 'in' | '=' | '!=') range_list
within_relation = expr ('not')? 'within' range_list
expr = operand (('mod' | '%') value)?
operand = 'n' | 'i' | 'f' | 't' | 'v' | 'w'
range_list = (range | value) (',' range_list)*
value = digit+
digit = 0|1|2|3|4|5|6|7|8|9
range = value'..'value
samples = sampleRange (',' sampleRange)* (',' ('…'|'...'))?
sampleRange = decimalValue '~' decimalValue
decimalValue = value ('.' value)?
*/
// We don't evaluate the samples section of the rule. Ignore it.
rule = rule.split('@')[0].replace(/^\s*/, '').replace(/\s*$/, '');
if (!rule.length) {
// Empty rule or 'other' rule.
return true;
}
// Indicates the current position in the rule as we parse through it.
// Shared among all parsing functions below.
var pos = 0,
operand,
expression,
relation,
result,
whitespace = makeRegexParser(/^\s+/),
value = makeRegexParser(/^\d+/),
_n_ = makeStringParser('n'),
_i_ = makeStringParser('i'),
_f_ = makeStringParser('f'),
_t_ = makeStringParser('t'),
_v_ = makeStringParser('v'),
_w_ = makeStringParser('w'),
_is_ = makeStringParser('is'),
_isnot_ = makeStringParser('is not'),
_isnot_sign_ = makeStringParser('!='),
_equal_ = makeStringParser('='),
_mod_ = makeStringParser('mod'),
_percent_ = makeStringParser('%'),
_not_ = makeStringParser('not'),
_in_ = makeStringParser('in'),
_within_ = makeStringParser('within'),
_range_ = makeStringParser('..'),
_comma_ = makeStringParser(','),
_or_ = makeStringParser('or'),
_and_ = makeStringParser('and');
function debug() {
// console.log.apply(console, arguments);
}
debug('pluralRuleParser', rule, number);
// Try parsers until one works, if none work return null
function choice(parserSyntax) {
return function() {
var i, result;
for (i = 0; i < parserSyntax.length; i++) {
result = parserSyntax[i]();
if (result !== null) {
return result;
}
}
return null;
};
}
// Try several parserSyntax-es in a row.
// All must succeed; otherwise, return null.
// This is the only eager one.
function sequence(parserSyntax) {
var i, parserRes,
originalPos = pos,
result = [];
for (i = 0; i < parserSyntax.length; i++) {
parserRes = parserSyntax[i]();
if (parserRes === null) {
pos = originalPos;
return null;
}
result.push(parserRes);
}
return result;
}
// Run the same parser over and over until it fails.
// Must succeed a minimum of n times; otherwise, return null.
function nOrMore(n, p) {
return function() {
var originalPos = pos,
result = [],
parsed = p();
while (parsed !== null) {
result.push(parsed);
parsed = p();
}
if (result.length < n) {
pos = originalPos;
return null;
}
return result;
};
}
// Helpers - just make parserSyntax out of simpler JS builtin types
function makeStringParser(s) {
var len = s.length;
return function() {
var result = null;
if (rule.substr(pos, len) === s) {
result = s;
pos += len;
}
return result;
};
}
function makeRegexParser(regex) {
return function() {
var matches = rule.substr(pos).match(regex);
if (matches === null) {
return null;
}
pos += matches[0].length;
return matches[0];
};
}
/**
* Integer digits of n.
*/
function i() {
var result = _i_();
if (result === null) {
debug(' -- failed i', parseInt(number, 10));
return result;
}
result = parseInt(number, 10);
debug(' -- passed i ', result);
return result;
}
/**
* Absolute value of the source number (integer and decimals).
*/
function n() {
var result = _n_();
if (result === null) {
debug(' -- failed n ', number);
return result;
}
result = parseFloat(number, 10);
debug(' -- passed n ', result);
return result;
}
/**
* Visible fractional digits in n, with trailing zeros.
*/
function f() {
var result = _f_();
if (result === null) {
debug(' -- failed f ', number);
return result;
}
result = (number + '.').split('.')[1] || 0;
debug(' -- passed f ', result);
return result;
}
/**
* Visible fractional digits in n, without trailing zeros.
*/
function t() {
var result = _t_();
if (result === null) {
debug(' -- failed t ', number);
return result;
}
result = (number + '.').split('.')[1].replace(/0$/, '') || 0;
debug(' -- passed t ', result);
return result;
}
/**
* Number of visible fraction digits in n, with trailing zeros.
*/
function v() {
var result = _v_();
if (result === null) {
debug(' -- failed v ', number);
return result;
}
result = (number + '.').split('.')[1].length || 0;
debug(' -- passed v ', result);
return result;
}
/**
* Number of visible fraction digits in n, without trailing zeros.
*/
function w() {
var result = _w_();
if (result === null) {
debug(' -- failed w ', number);
return result;
}
result = (number + '.').split('.')[1].replace(/0$/, '').length || 0;
debug(' -- passed w ', result);
return result;
}
// operand = 'n' | 'i' | 'f' | 't' | 'v' | 'w'
operand = choice([n, i, f, t, v, w]);
// expr = operand (('mod' | '%') value)?
expression = choice([mod, operand]);
function mod() {
var result = sequence(
[operand, whitespace, choice([_mod_, _percent_]), whitespace, value]
);
if (result === null) {
debug(' -- failed mod');
return null;
}
debug(' -- passed ', parseInt(result[0], 10), result[2], parseInt(result[4], 10));
return parseFloat(result[0]) % parseInt(result[4], 10);
}
function not() {
var result = sequence([whitespace, _not_]);
if (result === null) {
debug(' -- failed not');
return null;
}
return result[1];
}
// is_relation = expr 'is' ('not')? value
function is() {
var result = sequence([expression, whitespace, choice([_is_]), whitespace, value]);
if (result !== null) {
debug(' -- passed is :', result[0], ' == ', parseInt(result[4], 10));
return result[0] === parseInt(result[4], 10);
}
debug(' -- failed is');
return null;
}
// is_relation = expr 'is' ('not')? value
function isnot() {
var result = sequence(
[expression, whitespace, choice([_isnot_, _isnot_sign_]), whitespace, value]
);
if (result !== null) {
debug(' -- passed isnot: ', result[0], ' != ', parseInt(result[4], 10));
return result[0] !== parseInt(result[4], 10);
}
debug(' -- failed isnot');
return null;
}
function not_in() {
var i, range_list,
result = sequence([expression, whitespace, _isnot_sign_, whitespace, rangeList]);
if (result !== null) {
debug(' -- passed not_in: ', result[0], ' != ', result[4]);
range_list = result[4];
for (i = 0; i < range_list.length; i++) {
if (parseInt(range_list[i], 10) === parseInt(result[0], 10)) {
return false;
}
}
return true;
}
debug(' -- failed not_in');
return null;
}
// range_list = (range | value) (',' range_list)*
function rangeList() {
var result = sequence([choice([range, value]), nOrMore(0, rangeTail)]),
resultList = [];
if (result !== null) {
resultList = resultList.concat(result[0]);
if (result[1][0]) {
resultList = resultList.concat(result[1][0]);
}
return resultList;
}
debug(' -- failed rangeList');
return null;
}
function rangeTail() {
// ',' range_list
var result = sequence([_comma_, rangeList]);
if (result !== null) {
return result[1];
}
debug(' -- failed rangeTail');
return null;
}
// range = value'..'value
function range() {
var i, array, left, right,
result = sequence([value, _range_, value]);
if (result !== null) {
debug(' -- passed range');
array = [];
left = parseInt(result[0], 10);
right = parseInt(result[2], 10);
for (i = left; i <= right; i++) {
array.push(i);
}
return array;
}
debug(' -- failed range');
return null;
}
function _in() {
var result, range_list, i;
// in_relation = expr ('not')? 'in' range_list
result = sequence(
[expression, nOrMore(0, not), whitespace, choice([_in_, _equal_]), whitespace, rangeList]
);
if (result !== null) {
debug(' -- passed _in:', result);
range_list = result[5];
for (i = 0; i < range_list.length; i++) {
if (parseInt(range_list[i], 10) === parseFloat(result[0])) {
return (result[1][0] !== 'not');
}
}
return (result[1][0] === 'not');
}
debug(' -- failed _in ');
return null;
}
/**
* The difference between "in" and "within" is that
* "in" only includes integers in the specified range,
* while "within" includes all values.
*/
function within() {
var range_list, result;
// within_relation = expr ('not')? 'within' range_list
result = sequence(
[expression, nOrMore(0, not), whitespace, _within_, whitespace, rangeList]
);
if (result !== null) {
debug(' -- passed within');
range_list = result[5];
if ((result[0] >= parseInt(range_list[0], 10)) &&
(result[0] < parseInt(range_list[range_list.length - 1], 10))) {
return (result[1][0] !== 'not');
}
return (result[1][0] === 'not');
}
debug(' -- failed within ');
return null;
}
// relation = is_relation | in_relation | within_relation
relation = choice([is, not_in, isnot, _in, within]);
// and_condition = relation ('and' relation)*
function and() {
var i,
result = sequence([relation, nOrMore(0, andTail)]);
if (result) {
if (!result[0]) {
return false;
}
for (i = 0; i < result[1].length; i++) {
if (!result[1][i]) {
return false;
}
}
return true;
}
debug(' -- failed and');
return null;
}
// ('and' relation)*
function andTail() {
var result = sequence([whitespace, _and_, whitespace, relation]);
if (result !== null) {
debug(' -- passed andTail', result);
return result[3];
}
debug(' -- failed andTail');
return null;
}
// ('or' and_condition)*
function orTail() {
var result = sequence([whitespace, _or_, whitespace, and]);
if (result !== null) {
debug(' -- passed orTail: ', result[3]);
return result[3];
}
debug(' -- failed orTail');
return null;
}
// condition = and_condition ('or' and_condition)*
function condition() {
var i,
result = sequence([and, nOrMore(0, orTail)]);
if (result) {
for (i = 0; i < result[1].length; i++) {
if (result[1][i]) {
return true;
}
}
return result[0];
}
return false;
}
result = condition();
/**
* For success, the pos must have gotten to the end of the rule
* and returned a non-null.
* n.b. This is part of language infrastructure,
* so we do not throw an internationalizable message.
*/
if (result === null) {
throw new Error('Parse error at position ' + pos.toString() + ' for rule: ' + rule);
}
if (pos !== rule.length) {
debug('Warning: Rule not parsed completely. Parser stopped at ', rule.substr(0, pos), ' for rule: ', rule);
}
return result;
}
return pluralRuleParser;
}));