gistfile1.py

    @compose(E.ControlStructureExpression)
    @compose(list)
    def linked_control_structure_stmt(self, initial, pos0):
        linking_structure = self.linked_control_structures[self.current_token().string]
        while True:
            pos = self.current_token().pos
            name = self.get_token().string
            options = linking_structure[name]
            params = []
            i, j = 0, 0
            while not self.accept('colon'):
                if i >= len(options):
                    self.expect('colon')

                if j >= len(options[i]):
                    j = 0
                    i += 1

                if options[i][j] is None:
                    params.append(self.test())
                else:
                    params.append(E.SymbolExpression(self.get_token()))
                j += 1
            else:
                if i != len(options) and j != len(options[i]):
                    if options[i][j] is None:
                        self.raise_unexpected()
                    else:
                        self.expect_symbol(options[i][j])
                self.next_token()
            suite = self.suite()
            yield E.ControlStructureLinkExpression(name, params, suite, pos)

            if not self.accept_symbol(*self.acceptable_lcs_successors(initial)):
                break