'''Pluralize English nouns (stage 6)

Command line usage:

$ python plural6.py noun

nouns

'''

import re

def build_match_and_apply_functions(pattern, search, replace):

def matches_rule(word):

return re.search(pattern, word)

def apply_rule(word):

return re.sub(search, replace, word)

return [matches_rule, apply_rule]

class LazyRules:

rules_filename = 'plural6-rules.txt'

def __init__(self):

self.pattern_file = open(self.rules_filename, encoding='utf-8')

self.cache = []

def __iter__(self):

self.cache_index = 0

return self

def __next__(self):

self.cache_index += 1

if len(self.cache) >= self.cache_index:

return self.cache[self.cache_index - 1]

if self.pattern_file.closed:

raise StopIteration

line = self.pattern_file.readline()

if not line:

self.pattern_file.close()

raise StopIteration

pattern, search, replace = line.split(None, 3)

funcs = build_match_and_apply_functions(

pattern, search, replace)

self.cache.append(funcs)

return funcs

rules = LazyRules()

def plural(noun):

for matches_rule, apply_rule in rules:

if matches_rule(noun):

return apply_rule(noun)

if __name__ == '__main__':

import sys

if sys.argv[1:]:

print(plural(sys.argv[1]))

else:

print(__doc__)

# Copyright (c) 2009, Mark Pilgrim, All rights reserved.

#

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# are permitted provided that the following conditions are met:

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# * Redistributions of source code must retain the above copyright notice,

# this list of conditions and the following disclaimer.

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# this list of conditions and the following disclaimer in the documentation

# and/or other materials provided with the distribution.

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# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

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# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE

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