Re: Just can't hear enough about Cells?

Ken Tilton <kentilton@xxxxxxxxx> writes:
Frank Buss wrote:
Ken Tilton wrote:


Gee, are Pythonistas smarter than Lispniks?!:

http://www.eby-sarna.com/pipermail/peak/2006-May/002545.html


This sounds interesting. Maybe more people would be interested in Lisp
Cells, too, if some ideas of this text would be added to the Cells
documentation. Looks like currently there is not much documentation or
papers about the concepts at all.

Oh, yes, it's all my fault. PWUAHAHAHAHAAH! Which sections of which
docs, examples, and Usenet articles were confusing to you? Or should I
just guess at that from the profound silence of the CL commuity and
rewrite all of that every week until someone says something?

I must confess that until I read the pipermail article I
hadn't grasped why Cells was interesting. If we are having a
competition for a very short but intriguing Cells intro here
is my entry:

`Cells' tracks and manages dependencies for you. For example
if X and Y are exogenous variables, A and B endogenous
variables and F and G functions, with

A = (F X Y) and B = (G A X)

when you update Y, Cells will update A and also propagate
the change, updating B as well.

Why use Cells? Why not just roll your own as needed?
Well, there is more to this than meets the eye. Consider
updating X. A naive dependency tracker may update B (because
X changed) then update A before finally updating B again
because A changed. Worse, it might not do this, depending on
the order in which A and B are declared.

Cells does the right thing, queuing the updates in the
efficient order, with B being updated exactly once, after A.
Choosing to use the Cells framework lets you design out
a whole class of subtle dependency bugs.

Marks out of 10 please Ken?

Alan Crowe
Edinburgh
Scotland

.

Relevant Pages

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  • I never did this before...
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    (comp.lang.lisp)