Squeak and Namespaces

James Foster james at foster.net
Thu Nov 30 17:23:00 UTC 2006


Hi,

> -----Original Message-----
> From: squeak-dev-bounces at lists.squeakfoundation.org [mailto:squeak-dev-
> bounces at lists.squeakfoundation.org] On Behalf Of J J
> Sent: Wednesday, November 29, 2006 10:21 PM
> To: squeak-dev at lists.squeakfoundation.org
> Subject: RE: Squeak and Namespaces
> 
> >From: "James Foster" <james at foster.net>
> >Reply-To: james at foster.net, The general-purpose Squeak developers
> >list<squeak-dev at lists.squeakfoundation.org>
> >To: "'Michael van der Gulik'" <mikevdg at gmail.com>
> >CC: 'The general-purpose Squeak developers
> >list'<squeak-dev at lists.squeakfoundation.org>
> >Subject: RE: Squeak and Namespaces
> >Date: Wed, 29 Nov 2006 21:58:49 -0800
> >
> >Importantly, there is no change in the language syntax. The "magic"
> happens
> >during method compilation where one of the arguments to the compiler is
> the
> >SymbolList instance that is to be searched for any needed global
> >references.
> >Different methods can be compiled with reference to different SymbolList
> >instances, and still call each other. This allows for private classes,
> >class
> >replacement, etc. It has served reasonably well for a couple decades.
> >
> 
> This is all very interesting.  So I guess the given user has to be
> explicitly set up to use any namespace they get?  

By default, the existing tools that create a new user give the new user a
specified subset of the existing SymbolDictionary instances.

> And if one is added you
> rebuild all the places the user is being implicit since he may now be
> talking about a totally different class even though his code didn't
> change?

If a new SymbolDictionary is added to the image then it is not visible to a
user till it is added to that user's SymbolList. Adding it to a user's
SymbolList only impacts methods that are compiled later. Compiled code
remains bound to the globals (Association) referenced when the methods were
compiled. If you wanted to change the bindings, you would need to recompile
the methods. 

James




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