Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!bloom-beacon!gatech!udel!rochester!pt.cs.cmu.edu!andrew.cmu.edu!mp1u+ From: mp1u+@andrew.cmu.edu (Michael Portuesi) Newsgroups: comp.sys.amiga Subject: Re: How 'Bout HyperCard! Message-ID: Date: 23 May 88 06:03:38 GMT References: <15372@uflorida.cis.ufl.EDU> <31411@linus.UUCP> <3768@cbmvax.UUCP> <2019@sugar.UUCP>, <1002@sandino.quintus.UUCP> Organization: Carnegie Mellon Lines: 59 In-Reply-To: <1002@sandino.quintus.UUCP> Peter Schachte writes: > But a hypertext system SHOULD. The point is that this approach makes it > possible to deliver small components. By this I don't mean, say, an > individual bar chart, but a new KIND of chart. IFF lets me deliver > individual bar charts. It makes it possible for me to invent a new kind > of chart, but only as part of a program I'm delivering. If someone > wants to be able to incorporate this kind of chart into a document, they > have to convince a purveyor of word processors to do the work. An > object-oriented system would allow the encapsulation of the methods for > handling this type of chart in a single place, so that any program could > use it without having to know about it ahead of time, other than to know > the names of the methods it must support. Peter has it right on the money. Any of you with access to the X11 distribution should take a long, serious look at the Andrew Toolkit, which was distributed on the X tape. ATK is an object-oriented user-interface toolbox that allows one to define a class and methods for user interface objects, and to allow applications to dynamically load these objects in the course of program execution. Each object has a number of "default methods" it must provide -- a FullUpdate method, a method to initialize an instance of this object, and so on. The neat thing is is that if you implement all of these methods, an ATK-based application can use your object without ever having known about it before. There are classes defined for text, raster images, structured-graphics, animations, requesters/dialog boxes, etc. etc. EZ, which is an ATK editor, is capable of editing any ATK object, since it dynamically loads the object plus all of the methods that are needed to work with it. It does not have to know what the object looks like in advance. For example, you can define a Calculator object plus all of the methods of interaction with it. In an EZ document, you can paste the calculator right in the middle and do calculations with your document! Similarly, Messages (the mail-bboard interface that runs on Andrew) allows users to mail or post raster images and other ATK objects anywhere on the system. I should point out that the net.gods have taken notice of this, and want to extend the current Usenet news software to use ATK as a standard for information exchange. Thus in the not-too-far future you may be able to mail and post ATK objects on Usenet. I would really like to see such a system on the Amiga. IFF standards and an iff.library are nice, but they supply exactly the same kind of capability that machines like the Mac currently have. ATK works with X and the Andrew Window Manager, but it was designed to offer independence of particular window system architectures. I'm not saying that ATK is *the* answer (programs written with ATK do tend to be quite large), but such a system would give the Amiga a capability that no other personal computer (or workstation not running the Andrew environment, for that matter) offers. Michael Portuesi / Information Technology Center / Carnegie Mellon University ARPA/UUCP: mp1u+@andrew.cmu.edu BITNET: rainwalker@drycas "if you ain't ill it'll fix your car"