在向列表添加一个元素后进行长时间处理

Question

在以下代码中，如果我只在列表 规则 中添加一个元素，则处理时间会呈指数级增长：

def rules_generator():
    generated_rules = dict()
    dictionary = {'<PLACE>': ['hospital', 'market'], '<DRINK>': ['Fanta', 'beer']}
    rules = ['go to <PLACE>', '<DRINK> for drinking in <PLACE>', 'love it']
    for r in rules:
        rule = r
        if re.search('\<[A-Z]+?\>', r):
            node_list = re.findall('\<[A-Z]+?\>', r)
            for node in node_list:
                expanded_node = '(' + '|'.join(dictionary[node]) + ')'
                r = re.sub(node, expanded_node, r)
            generated_rules[rule] = r
        else:
            generated_rules[rule] = r
    return generated_rules

def analyzer(text):
    generated_rules = rules_generator()
    for rule, expanded_rule in generated_rules.items():
        if re.search(expanded_rule,text):
            print True

corpus = open('corpus.txt', 'r')
for l in corpus:
    print analyzer(l)