🚀 go-pugleaf

For starters, why would you want to separate the "core" of your app from the  
UI?  Well, the obvious answer is "to make the core portable among different  
operating systems and environments".

That is certainly a big reason.  More generally, this is true if you wish to  
write a core portable among multiple interfaces (writing X code for Motif and  
OpenLook, or something).  In other words, one would do this to buffer the core  
from the interface driving it.

This comes up when providing an API for your application; the API usually  
duplicates functionality obtained in the application, but allows other  
services/apps to access its power without going through the user interface.  In  
a sense, the API is a second, more powerful but less accessible interface to  
the application.

Under NeXTstep, this problem is somewhat more urgent with the advent of  
Distributed Objects.  Making your app accessible via an API that someone can  
access from another machine on the same network allows tremendous leverage and  
the possibility of developing lightweight objects which can do major tasks in  
combination with each other.  If your app is entirely menu/panel driven, or  
stores state in the UI (very common with TextFields, FormCells, etc) then it  
can be hard to allow someone to leverage your work.  If, on the other hand,  
your app stores all its own state and accesses the UI through another object  
(which in itself uses the core's API), then Distributed Objects is a snap.

The reason I'm interested in this core-UI thing is the last; I'm interested in  
developing objects and palettes for Canon Information Systems to run various  
scanning devices.  Packing these objects as NeXTstep palettes means I have to  
figure out what kind of an interface to give the developer, and how to provide  
a flexible interface to the scanner for Distributed Objects.

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Subrata Sircar|ssircar@canon.com (NextMail ok)|Prophet & SPAMIT Charter Member
Canon Information Systems and I do not share the same views on everything.
"I'm just mad that I missed the sexual revolution." - me
"Yes, but you dress much better as a result." - Mike