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Re: Perl 6 Summary

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Larry Wall
July 6, 2002 19:57
Re: Perl 6 Summary
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On Sun, 7 Jul 2002, Thom Boyer wrote:
: Has there been any indication whether those suggestions have met
: with Larry's approval?

There will certainly be support for that sort of thing in Parrot,
up to and including continuations.  Otherwise we cannot hope to
host all these other languages.  Exactly how Perl will make the
interface known to its users is still up for grabs.  Hopefully we
can be specific enough that the compiler can figure out when it has
to use continuations and when it can use some lighter mechanism.

From a language design point of view, we want fancy control structures
to just kind of sneak into people's consciences just as closures did in
Perl 5.  The capabilities should be there, but they should just work
the way you expect when you get to having any expectations whatsover.
It'd be really nice to find a way to explain continuations to people
without inflicting the typical torturous explanations on people who
aren't interested in brain pretzels.

Perhaps we should just explain continuations in terms of time travel.
Most people think they understand time travel, even when they don't.
A continuation is just a funny label for a point in time, and you have
a way of sending messages from the future back to that point in time.

Another way of looking at it is that a continuation is a hypothesis
about the future, and calling the continuation is a way of saying
"oops" about that hypothesis.

Basically, we need to find the right oversimplification to make people
think they understand it.  Kind of like cancelling the dx's and dy's
in calculus--the physics profs always tell you to do that, while
warning you not to tell the math profs they're telling you to do that,
because it doesn't always work, except in real life.


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