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Re: original meaning of System` functions

  • To: mathgroup at smc.vnet.net
  • Subject: [mg115446] Re: original meaning of System` functions
  • From: Yuri Kandrashkin <spinalgebra at gmail.com>
  • Date: Tue, 11 Jan 2011 06:58:02 -0500 (EST)

My 2 cents:



   1. The functions which code is planning to hide should not have attribute
   Protected and Locked because this prevents some operations like SetOptions
   etc. It is better to refer to a separate function, which must have
   attributes Locked, Protected, and ReadProtected.
   For example:
   Func[args__,opts:OptionPattern[]] :== func[args,opts];
   definition of func
   SetAttributes[func,{Locked, Protected, ReadProtected}];
   2. In general it is convenient to separate the code packages and loading
   package. In this case the code packages should be encrypted with a key. The
   loading package should be also encrypted with or without key depending on
   the application distribution conditions.
   3. The loading package should solve the following tasks:
   - Checking if the crucial System functions have been changed. This task
   is most complicate and currently I don't know any bulletproof solution
   unless WRI will provide a block-like function in which it would be allowed
   to use only unmodified functions of the Mathematica kernel.
   - Checking of the existence of the functions of your applications. It is
   quite simple to get a code of the function if one sets the attribute Locked
   BEFORE the loading its definitions. At this stage the full names should be
   used to prevent shadowing.
   - Loading the code packages applying the key if the previous tests
   haven't failed.

Yuri

2011/1/11 hemmecke <hemmecke at gmail.com>

On Jan 10, 8:38 am, DrMajorBob <btre... at austin.rr.com> wrote:
> > I suppose you could export brief "shell" functions that call the ones
> you==
>
> > want to hide (which you would not export).
>
> Since Mathematica has no concept of a proper namespace, there is
> actually no difference between "exported" and "non-exported". You can
> easily get all the names of the package P by asking for
>
>  Names["P`*"]
>  Names["P`Private`*"]
>
> Then
>
>  ??P`Private`F
>
> for some function F listed above, will show you the source.
>
> Can you please detail a bit more of what you mean?
>
> Ralf
>
>


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