[racket] Pass by value/name/reference

Thank U very much,
Our project is about "programming language principle". during the semester
we have been programming a compiler for Jack language in racket,
and now we need to make a presentation on Racket language that includes all
information about the principle that we learned.


2014-07-21 5:31 GMT+03:00 Matthias Felleisen <matthias at ccs.neu.edu>:

>
> On Jul 20, 2014, at 9:25 PM, Jon Zeppieri wrote:
>
> > On Sun, Jul 20, 2014 at 6:27 PM, Matthias Felleisen
> > <matthias at ccs.neu.edu> wrote:
> >>
> >> The phrase "call-by-value is a reduction strategy" has no meaning per
> se but is a left over from the time when people hadn't figured out the
> above (pre 1070).
> >>
> >
> > I apologize for spreading this nonsense. Is it the phrase "reduction
> > strategy" that's the problem? In the paper you cited, you refer to
> > "evaluation strategies" and "binding strategies" and list
> > call-by-value (eager) and call-by-name (delayed) as examples of the
> > former. Is the problem with "reduction strategy" that it properly
> > refers to rules for reducing redexes in a lambda calculus (and not
> > parameter-passing in a programming language)? Or is it just nonsense
> > tout court?
>
>
> Yeap. Strategies exist in any LC. A strategy is simply a function
> that picks the next redex to reduce. Strategies have uses BUT not
> to describe parameter-passing mechanism. The latter are turned into
> axioms directly. For example
>
>  BY NAME: (function (x) body) any-argument = body with all (free) x
> replaced by any-argument
>  BY VALUE: (function (x) body) value-argument = body with all (free) x
> replaced by value-argument
>
> So you see there are two calculi and they each come with a different
> axiom but the SAME strategies.
>
> ;; ---
>
> The idea is so much ingrained in programmer's mind due to some
> basic text books that I can't blame anybody and I am certainly
> not blaming you.
>
> I just don't like it that the idea is repeated 40+ years
> after it was debunked in my neighborhood :-)
>
> -- Matthias
>
>
>
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