ieml/grammar/parser/parser.py
def p_proposition_sum(self, p):
        """word_sum : word_sum PLUS word
                    | word
            clauses_sum : clauses_sum PLUS clause
                    | clause
            superclauses_sum : superclauses_sum PLUS superclause
                    | superclause"""

        # closed_proposition_list : closed_proposition_list closed_proposition
        #                         | closed_proposition"""
        if len(p) == 4:
            p[0] = p[1] + [p[3]]
        elif len(p) == 3:
            p[0] = p[1] + [p[2]]
        else:
            p[0] = [p[1]]
def p_proposition_sum(self, p):
        """word_sum : word_sum PLUS word
                    | word
            clauses_sum : clauses_sum PLUS clause
                    | clause
            superclauses_sum : superclauses_sum PLUS superclause
                    | superclause"""

        # closed_proposition_list : closed_proposition_list closed_proposition
        #                         | closed_proposition"""
        if len(p) == 4:
            p[0] = p[1] + [p[3]]
        elif len(p) == 3:
            p[0] = p[1] + [p[2]]
        else:
            p[0] = [p[1]]
word_sum : word_sum PLUS word
                    | word
            clauses_sum : clauses_sum PLUS clause
                    | clause
            superclauses_sum : superclauses_sum PLUS superclause
                    | superclause