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Re: Packaged Dynamic Problem

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  • Subject: [mg104044] Re: Packaged Dynamic Problem
  • From: Albert Retey <awnl at>
  • Date: Fri, 16 Oct 2009 07:22:13 -0400 (EDT)
  • References: <hb70an$8sf$>


> I have this interesting problem, where a package interferes with
> global variables, and I cannot even find the root of this problem. I
> managed to scale down the issue to a toy model, concerning two files,
> a working notebook, and a package. You can guess, it wasn't easy.
> The working notebook (one cell):
> DynamicModule[{x = 0}, {Slider[Dynamic@x, {-1, 1}], Dynamic@x},
> Initialization :> Needs@"Test`"]
> And the package file (named Test.nb, and also .m, one cell):
> BeginPackage["Test`"];
> FirstFunction::usage = "";
> Verbose::usage =
>   If[ValueQ[Verbose::usage], Verbose::usage <> "some text",
>    "other text"];
> Begin["`Private`"];
> End[];
> EndPackage[];
> On my system (7.0.1, WinXP SP2) the working notebook takes at least
> for 25 seconds to evaluate (with a fresh kernel), during which my
> whole system freezes, and then drops a "One or more dynamic objects
> are taking excessively long to finish..." dialogue. I can hit the
> 'Continue waiting' button, and the slider+value list immediately
> appears, but this shouldn't take 25 seconds. (Of course, in this
> model, there is no need to call for the Test` package, but
> nevertheless, it seems to be the cause of the problem.)
> Also if I re-evaluate the DynamicModule (without restarting the
> kernel), it gives me an error message:
> x$$::shdw: Symbol x$$ appears in multiple contexts {Test`,Global`};
> definitions in context Test` may shadow or be shadowed by other
> definitions. >>
> Clearly there is no x$$ variable defined in Test`, so I don't
> understand this message.
> The most peculiar thing is that removing either of the usage messages
> (with lhs and rhs) from the package seems to solve the problem, at
> least in my case. Thus the issue is not specific on one message. I
> have no idea how I should advance from this point.
> Can anyone reproduce this issue?

no, I just have tried it and it seems to work without problems (Mathematica
7.0.1, Windows XP SP2).

> Can anyone comment on it?

not really, but are you sure you are loading the package you want to?
Have you looked at the m-file you are loading with a text editor to make
sure it doesn't contain anything unexpected?



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