From lliao@ren.eecis.udel.edu Thu Oct 10 22:56:21 2002
Date: Thu, 10 Oct 2002 22:55:22 -0400 (EDT)
From: Li Liao <lliao@ren.eecis.udel.edu>
To: Natasha Duncan <natasha@udel.edu>
Subject: Re: mult test option in hw2




On Thu, 10 Oct 2002, Natasha Duncan wrote:

> case mult leaves me with this error message:
....
>
> uncaught exception TypeError
>
> When I think of it, the compiler has a right to complain,
> because we just pushed two Numbers on the value stack with
> read and later pushed a value of type (Name "y").
> The homework defines exch as "pop the two numbers, swap
> them an put them back"(that's how I implemented it in my
> code - checking that the two values popped are numbers).
> In our case we don't have two numbers, but have and Name
> and two numbers.
> Should the definition of  exch be "pop two values from the top,
> swap them and push them back"?

You are definitely right. I guess I meant to say pop two "values"
and I do not know why I put it as two "numbers". Thanks for pointing that
out.

Li