The formal semantics makes no claim to let you reason about the space
behavior of your program!
You've said twice now that you think the formal semantics is
incorrect. Your explanations of why don't seem right to me, but they
are still vague. Please explain (unless you were talking about space
both times?)
Robby
On 3/15/07, AndrevanTonder <andre_at_het.brown.edu> wrote:
> On Thu, 15 Mar 2007, Robby Findler wrote:
>
> >> This is not obvious to me. Doesn't simple substitution have the danger of
> >> leading to exponential explosion in size due to unnecessary copying of the
> >> argument throughout the body? I would think that this would happen for
> >> many
> >> common programs, making them harder to follow.
> >
> > Substitution is a very simple way to think of function application,
> > going back to some of our earliest exposure to mathematics in school
> > (at least in this country).
>
> I don't dispute that, but this is not how the text describes function
> application.
>
> While being pedagogical is not a bad secondary goal, a formal semantics must be
> correct first. I would like to be able to reason about the space behaviour of
> a program using the formal semantics. Direct substitution can change a
> program's space behaviour from polynomial to exponential.
>
> Given this, as far a space behaviour is concerned, the current semantics is
> incorrect (compared with the body of the report).
>
> Andre
>
Received on Thu Mar 15 2007 - 12:52:21 UTC