Respond to text entered by the user.

        :param text: the user's input

def eval(self, text):
        """Respond to text entered by the user.

        :param text: the user's input
        """
        program = Program(text, echo=self.echo, transforms=self.transforms)
        tokens = program.gen_tokens()
        for sentence in program.gen_sentences(tokens, self.aliases):
            if self.echo:
                self.terminal.debug(str(sentence))
            program.interpret(sentence, self.commands)