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+++ b/compare_locales/plurals.py
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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/.
+
+'Mapping of locales to CLDR plural categories as implemented by PluralForm.jsm'
+
+CATEGORIES_BY_INDEX = (
+    #0 (Chinese)
+    ('other',),
+    #1 (English)
+    ('one', 'other'),
+    #2 (French)
+    ('one', 'other'),
+    #3 (Latvian)
+    ('zero', 'one', 'other'),
+    # 4 (Scottish Gaelic)
+    ('one', 'two', 'few', 'other'),
+    #5 (Romanian)
+    ('one', 'few', 'other'),
+    #6 (Lithuanian)
+    # CLDR: one, few, many (fractions), other
+    ('one', 'other', 'few'),
+    #7 (Russian)
+    # CLDR: one, few, many, other (fractions)
+    ('one', 'few', 'many'),
+    #8 (Slovak)
+    # CLDR: one, few, many (fractions), other
+    ('one', 'few', 'other'),
+    #9 (Polish)
+    # CLDR: one, few, many, other (fractions)
+    ('one', 'few', 'many'),
+    #10 (Slovenian)
+    ('one', 'two', 'few', 'other'),
+    # 11 (Irish Gaelic)
+    ('one', 'two', 'few', 'many', 'other'),
+    #12 (Arabic)
+    # CLDR: zero, one, two, few, many, other
+    ('one', 'two', 'few', 'many', 'other', 'zero'),
+    #13 (Maltese)
+    ('one', 'few', 'many', 'other'),
+    #14 (Macedonian)
+    # CLDR: one, other
+    ('one', 'two', 'other'),
+    #15 (Icelandic)
+    ('one', 'other'),
+    #16 (Breton)
+    ('one', 'two', 'few', 'many', 'other'),
+    #17 (Shuar)
+    # CLDR: (missing)
+    ('zero', 'other')
+)
+
+CATEGORIES_BY_LOCALE = {
+    'ach': CATEGORIES_BY_INDEX[1],
+    'af': CATEGORIES_BY_INDEX[1],
+    'an': CATEGORIES_BY_INDEX[1],
+    'ar': CATEGORIES_BY_INDEX[12],
+    'as': CATEGORIES_BY_INDEX[1],
+    'ast': CATEGORIES_BY_INDEX[1],
+    'az': CATEGORIES_BY_INDEX[0],
+    'be': CATEGORIES_BY_INDEX[7],
+    'bg': CATEGORIES_BY_INDEX[1],
+    'bn-BD': CATEGORIES_BY_INDEX[1],
+    'bn-IN': CATEGORIES_BY_INDEX[1],
+    'br': CATEGORIES_BY_INDEX[1],
+    'bs': CATEGORIES_BY_INDEX[1],
+    'ca': CATEGORIES_BY_INDEX[1],
+    'cak': CATEGORIES_BY_INDEX[1],
+    'cs': CATEGORIES_BY_INDEX[8],
+    'cy': CATEGORIES_BY_INDEX[1],
+    'da': CATEGORIES_BY_INDEX[1],
+    'de': CATEGORIES_BY_INDEX[1],
+    'dsb': CATEGORIES_BY_INDEX[10],
+    'el': CATEGORIES_BY_INDEX[1],
+    'en-GB': CATEGORIES_BY_INDEX[1],
+    'en-US': CATEGORIES_BY_INDEX[1],
+    'en-ZA': CATEGORIES_BY_INDEX[1],
+    'eo': CATEGORIES_BY_INDEX[1],
+    'es-AR': CATEGORIES_BY_INDEX[1],
+    'es-CL': CATEGORIES_BY_INDEX[1],
+    'es-ES': CATEGORIES_BY_INDEX[1],
+    'es-MX': CATEGORIES_BY_INDEX[1],
+    'et': CATEGORIES_BY_INDEX[1],
+    'eu': CATEGORIES_BY_INDEX[1],
+    'fa': CATEGORIES_BY_INDEX[0],
+    'ff': CATEGORIES_BY_INDEX[1],
+    'fi': CATEGORIES_BY_INDEX[1],
+    'fr': CATEGORIES_BY_INDEX[2],
+    'fy-NL': CATEGORIES_BY_INDEX[1],
+    'ga-IE': CATEGORIES_BY_INDEX[11],
+    'gd': CATEGORIES_BY_INDEX[4],
+    'gl': CATEGORIES_BY_INDEX[1],
+    'gn': CATEGORIES_BY_INDEX[1],
+    'gu-IN': CATEGORIES_BY_INDEX[2],
+    'he': CATEGORIES_BY_INDEX[1],
+    'hi-IN': CATEGORIES_BY_INDEX[1],
+    'hr': CATEGORIES_BY_INDEX[7],
+    'hsb': CATEGORIES_BY_INDEX[10],
+    'hu': CATEGORIES_BY_INDEX[1],
+    'hy-AM': CATEGORIES_BY_INDEX[1],
+    'ia': CATEGORIES_BY_INDEX[1],
+    'id': CATEGORIES_BY_INDEX[0],
+    'is': CATEGORIES_BY_INDEX[15],
+    'it': CATEGORIES_BY_INDEX[1],
+    'ja': CATEGORIES_BY_INDEX[0],
+    'ja-JP-mac': CATEGORIES_BY_INDEX[0],
+    'jiv': CATEGORIES_BY_INDEX[17],
+    'ka': CATEGORIES_BY_INDEX[0],
+    'kab': CATEGORIES_BY_INDEX[1],
+    'kk': CATEGORIES_BY_INDEX[1],
+    'km': CATEGORIES_BY_INDEX[1],
+    'kn': CATEGORIES_BY_INDEX[1],
+    'ko': CATEGORIES_BY_INDEX[0],
+    'lij': CATEGORIES_BY_INDEX[1],
+    'lo': CATEGORIES_BY_INDEX[0],
+    'lt': CATEGORIES_BY_INDEX[6],
+    'ltg': CATEGORIES_BY_INDEX[3],
+    'lv': CATEGORIES_BY_INDEX[3],
+    'mai': CATEGORIES_BY_INDEX[1],
+    'mk': CATEGORIES_BY_INDEX[15],
+    'ml': CATEGORIES_BY_INDEX[1],
+    'mr': CATEGORIES_BY_INDEX[1],
+    'ms': CATEGORIES_BY_INDEX[1],
+    'my': CATEGORIES_BY_INDEX[1],
+    'nb-NO': CATEGORIES_BY_INDEX[1],
+    'ne-NP': CATEGORIES_BY_INDEX[1],
+    'nl': CATEGORIES_BY_INDEX[1],
+    'nn-NO': CATEGORIES_BY_INDEX[1],
+    'oc': CATEGORIES_BY_INDEX[1],
+    'or': CATEGORIES_BY_INDEX[1],
+    'pa-IN': CATEGORIES_BY_INDEX[1],
+    'pl': CATEGORIES_BY_INDEX[9],
+    'pt-BR': CATEGORIES_BY_INDEX[1],
+    'pt-PT': CATEGORIES_BY_INDEX[1],
+    'rm': CATEGORIES_BY_INDEX[1],
+    'ro': CATEGORIES_BY_INDEX[1],
+    'ru': CATEGORIES_BY_INDEX[7],
+    'si': CATEGORIES_BY_INDEX[1],
+    'sk': CATEGORIES_BY_INDEX[8],
+    'sl': CATEGORIES_BY_INDEX[10],
+    'son': CATEGORIES_BY_INDEX[1],
+    'sq': CATEGORIES_BY_INDEX[1],
+    'sr': CATEGORIES_BY_INDEX[7],
+    'sv-SE': CATEGORIES_BY_INDEX[1],
+    'ta': CATEGORIES_BY_INDEX[1],
+    'te': CATEGORIES_BY_INDEX[1],
+    'th': CATEGORIES_BY_INDEX[0],
+    'tl': CATEGORIES_BY_INDEX[1],
+    'tr': CATEGORIES_BY_INDEX[0],
+    'trs': CATEGORIES_BY_INDEX[1],
+    'uk': CATEGORIES_BY_INDEX[7],
+    'ur': CATEGORIES_BY_INDEX[1],
+    'uz': CATEGORIES_BY_INDEX[0],
+    'vi': CATEGORIES_BY_INDEX[1],
+    'wo': CATEGORIES_BY_INDEX[1],
+    'xh': CATEGORIES_BY_INDEX[1],
+    'zam': CATEGORIES_BY_INDEX[1],
+    'zh-CN': CATEGORIES_BY_INDEX[1],
+    'zh-TW': CATEGORIES_BY_INDEX[0]
+}