A python class that parses and rewrite feature-sentiment queries in a form that can be consumed by Solr

queryparser

class QueryParser:
	""" Parses and rewrite feature-sentiment queries in Solr/Lucene syntax """

	def parse(self, query):
		assert isinstance(query, str)

		tokens = query.split()
		result = []

		for index in range(len(tokens)):	

			if tokens[index].endswith("+"):
				entry = (tokens[index][:-1], 1)
			elif tokens[index].endswith("-"):
				entry = (tokens[index][:-1], -1)
			else:
				entry = (tokens[index], 0)
			
			result.append(entry)

		return result


	def rewrite(self, query):
		assert isinstance(query, str)

		rewritten = []

		for feature, sentiment in self.parse(query):
			if sentiment == 1:
				rewritten.append("(feature:{} AND polarity:[0 TO *])".format(feature))
			elif sentiment == -1:
				rewritten.append("(feature:{} AND polarity:[* TO 0])".format(feature))
			elif sentiment == 0:
				rewritten.append("feature:{}".format(feature))
			else:
				pass

		return " OR ".join(rewritten).strip()


if __name__ == "__main__":
	from pprint import pprint

	query = "customer service+ wifi+ parking+ noise- swimming pool-"
	parser = QueryParser()
	pprint(parser.rewrite(query))