Re: Why does Manipulate leak global symbols? (Potential bug here?)
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- Subject: [mg123911] Re: Why does Manipulate leak global symbols? (Potential bug here?)
- From: David Reiss <dbreiss at gmail.com>
- Date: Fri, 30 Dec 2011 07:03:33 -0500 (EST)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
- References: <jd71p5$140$1@smc.vnet.net> <jdeqc2$8op$1@smc.vnet.net> <jdh6eb$kln$1@smc.vnet.net>
P.S. I submitted this a s a bug report to WRI.
--David
On Dec 29, 2:55 am, Szabolcs Horv=E1t <szhor... at gmail.com> wrote:
> It appears these symbols are created during the formatting (display) of
> the Manipulate object, and not while the Manipulate function runs.
>
> On 2011.12.28. 11:17, David Reiss wrote:
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> > This is presumably a bug in that what otherwise should be System
> > context (or some other Context) symbols are being placed into the
> > Global Context when they are being defined at the first instance of
> > the use of a Manipulate. One also comes across this as one uses
> > Mathematica -- not all symbols have been properly contextified: given
> > how many symbols exist, it's amazing that it doesn't happen more
> > often.
>
> > --David
>
> > On Dec 25, 6:35 am, Bill Rowe<readn... at sbcglobal.net> wrote:
> >> On 12/24/11 at 7:08 AM, szhor... at gmail.com (Szabolcs) wrote:
>
> >>> It appears that in Mathematica 8, using Manipulate will create some
> >>> symbols in the global context. Let me illustrate:
> >>> First, I use this to monitor the contents of Global` in real time:
> >>> Dynamic@Refresh[Sort@Names["Global`*"], UpdateInterval -> 2]
> >>> Then I evaluate Manipulate[n, {n, 1, 10}]
> >>> Note that the following unexpected symbols have been added to the
> >>> Global` context: BitDepth, FullScreenArea, Resolution, ScreenArea
>
> >>> Why does this happen? Is it a bug? Can it cause any problems (e=
.g.
> >>> if I have defined BitDepth before using Manipulate, in the belief
> >>> that there's no such builtin)?
>
> >> I can't answer as to why this happens. But I doubt that it is a
> >> bug and it seems to have no conflict with things you define.
> >> That is, if I first do
>
> >> BitDepth=2;
>
> >> then execute the code you posted in a fresh session, the value I
> >> assigned to BitDepth is unchanged. Alternatively, if I start a
> >> fresh session, execute the code above then type BitDepth in a
> >> new cell, I see BitDepth is colored consistent as any undefined
> >> symbol would be.
>
> >>> This makes me feel a bit insecure. I am not sure if I might
> >>> inadvertently break something by defining those symbols, thinking
> >>> that they're not used by Mathematica (since they're syntax-coloured
> >>> blue).
>
> >> It seems the best way to ensure no conflicts could occur is to
> >> simply use a lower case letter as the first letter of the name
> >> of anything you create.
>
> --
> Szabolcs Horv=E1t
> Mathematica QA site proposal:http://area51.stackexchange.com/proposals/37=
304