Thanks Ned. I'll poke around.  

> -----Original Message-----
> From: squeak-dev-bounces at lists.squeakfoundation.org 
> [mailto:squeak-dev-bounces at lists.squeakfoundation.org] On 
> Behalf Of Ned Konz
> Sent: Sunday, July 11, 2004 5:54 PM
> To: The general-purpose Squeak developers list
> Subject: Re: Reading in a project problem
> 
> On Sunday 11 July 2004 1:47 pm, Brad Fuller wrote:
> > > > "Reading an instance of <class>. Which modern class should it 
> > > > translate to?"
> > > >
> > > > With the following selections
> > > > 	Let me type the name now
> > > > 	Let me think about it
> > > > 	Let me find a conversion file on the disk.
> >
> > Thanks for the questions Ned!
> >
> > > Does the class that is reported exist in the image?
> >
> > No, the class(es) that are reported do not exist in the 
> image. Not on 
> > any of the machines.
> 
> That's the problem. The project file contains a serialized 
> version of the interesting objects in the project. But it 
> doesn't contain classes or method definitions, unless you 
> explicitly choose to store the change set with the project 
> (and unless the change set has all of the required definitions).
> 
> So a reference to a class is instead stored in a .pr file as 
> something that, when de-serialized, is equivalent to:
> 
> 	DiskProxy global: #YourClass selector: #yourself args: #()
> 
> and then is resolved by looking in the Smalltalk dictionary 
> under #YourClass.
> 
> But of course YourClass doesn't exist, and so Squeak offers 
> to let you either:
> 
> 	- load a change set that might include conversion methods
> 	- say that instances of YourClass should really become 
> instances of SomeOtherClass
> 	- stop loading
> 
> Look at implementors of #objectForDataStream: to find more 
> special cases like this.
> 
> If you want to distribute projects *and* your own code, the 
> easiest way to do it is either to:
> 	* ensure that all the class and method definitions you 
> need are in the project's change set (you can use the Dual 
> Change Sorter to copy methods from other change sets, as 
> necessary), or
> 	* package the .pr and the appropriate Smalltalk code 
> (.cs, .mcz, .st, etc.) inside a SAR file (a zip file that 
> Squeak knows how to load).
> 
> > I clearly need to know more about "projects". Can you point me in a 
> > direction of documentation?
> 
> What I do usually is either or both of:
> 
> 	- read the code (look here for 
> SmartRefStream/ReferenceStream, DiskProxy, and methods like 
> objectForDataStream: and the "file in/out" and "objects from 
> disk" method categories)
> 
> 	- poke around on the Squeak Swiki.
> 		http://minnow.cc.gatech.edu/squeak/1817
> 		http://minnow.cc.gatech.edu/squeak/2318
> 
> 	- do some Googling
> 
> --
> Ned Konz
> http://bike-nomad.com/squeak/
> 
> 
>