Re: [stack] Advantages of cat, joy ..?

On Feb 18, 2009, at 4:24 AM, John Nowak wrote:

>
> On Feb 18, 2009, at 3:07 AM, Don Groves wrote:
>
>> Then the teacher says to repeat the problem with the object sitting
>
>> on the floor next to the teacher's desk. The only acceptable answer
>> is to pick up the object and place it on the desk -- the rest of the
>> problem is already solved!
>>
>> Now, while this method of problem solving can be used in any
>> programming language, concatenative languages are built upon
>> this foundation. So, concatenative languages enable a programmer
>> to use provably-correct formal methods by their very nature.
>
> Interesting point. Two questions:
>
> 1) How much of this is due to the "flatness" of concatenative
> languages? In a flat concatenative language, it's as easy as it could
> possibly be to concatenate, splice, and otherwise manipulate programs.
> Nothing gets in your way.
>
> 2) If flatness helps, do first class quotations make things more
> difficult? Instead of being able to split at any point, quotations
> mean that you can only split within a certain context. I'm assuming
> the answer here is "yes", but I've not attempted to show this yet.
>
> If a large part of what makes concatenative languages well-suited to
> formal methods is their flat nature, then that would be a strong
> argument for the stack as the proper datatype for a concatenative
> language. My experiments with other datatypes have all resulted in a
> much more "nested" language with many additional functional forms.
> William has correctly remarked that they don't even "feel"
> concatenative.
>
> If first class quotations make things more difficult, then that would
> be a strong argument for trying the second order approach I've
> described previously; it keeps most of the benefits of the higher
> order approach while offering a trivial translation to a first order
> (i.e. "flat") program.

Not having much experience writing non-flat code, I'll have to pass
on passing any judgment as to which is better for what purposes.

I do feel quotations add to the usefulness of these languages
however, in spite of, as you point out, their removal of some of the
manipulations possible in a language such as Forth. Quotations
add many benefits, imho.
--
don


> - John
>
>
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