LOGO-L> Re: Why not a sequential ToonTalk?

["Ken Kahn" <KenKahn@ToonTalk.com>]

Brian Harvey wrote in message <73v2ml$lk6$1@agate.berkeley.edu>...
>I guess I'd like to know whether all paradigms are equally hard in this
>sense.  My teaching experience has made me (reluctantly!) conclude that
>sequential programming is most natural for most people, and that
>functional programming takes more mental effort (although the effort
>does pay off dramatically).  Where is concurrent programming on that
>scale?  What is the marginal cost of keeping function composition in
>a language, on that scale, versus the marginal cost of including
>concurrency?
>

Very good questions! Does anyone know of research trying to answer these
types of questions? Either in the computers and education literature or the
psychology of programming? (The only thing I can think of is Mitch Resnick's
masters thesis on MultiLogo.)

>>A pure functional component permits all sorts of program
>>transformations and parallel executions that break when integrated with
>>languages with side-effects.
>
>the functional one
>seems to me to be a bit of sleight-of-hand; there you are talking about
>complexity for the implementor, not cognitive load for the user.
>

How about concern for the order of execution of the arguments to a function?
In the pure case, you needn't bother yourself about this. If there might be
side-effects, you now have one more thing to keep in mind.

>
>I'm convinced that it's difficult to debug programs that combine
>concurrency with mutation of shared variables.  I'm not convinced, yet,
>that you can't have all of
> * concurrency
> * composition of functions without mutation
> * mutation of local (not shared) variables
>all in the same language, without trouble.
>
I'm not sure either. We'll just have to wait for someone to build it (or at
least design it in detail). But you'll agree that there is no dialect of
Logo that satisfies those criteria, right?

Best,

-ken kahn (www.toontalk.com)






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