[Newbies] Image vs. source code (was Re: Very Basic Squeak information)

David Douthitt ssrat at mailbag.com
Wed Nov 22 00:10:54 UTC 2006


Stephen Austin wrote:
> On 11/21/06, Bert Freudenberg <bert at freudenbergs.de> wrote:
> 
>> That's a thing you have to deeply understand. In all object-oriented
>> systems that are *not* image-based (which is the huge majority)...
> 
> Just curious - can you name any others which are image-based in the
> same way as Smalltalk/Squeak?

How about Common LISP (with CLOS) and FORTH for two?  FORTH isn't OOP, 
but at least one author described how an OOP FORTH could be done (Dick 
Pountain).  FORTH doesn't save "images" as much as they utilize the 
source code model: start up with the core, and load extensions from 
source.  Other than that, the model is the same.

This "image-based" idea is what makes FORTHers - or LISPers - or 
Smalltalkers roll their eyes and sigh heavily (figuratively 
speaking!!) when someone says: "Yes, but how do I save JUST MY PROGRAM 
into an executable?"

In all three languages, one works in a complete environment, and 
"saving a program" either means saving the source code to be read in 
or saving the environment image.


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