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Aucbvax.4853 fa.editor-p utzoo!decvax!ucbvax!editor-people Sat Oct 31 12:17:53 1981 Re: Integrating Editors with Programming Languages >From Admin.JQJ@SU-SCORE Sat Oct 31 12:09:21 1981 First, an aside and comment on GJC's comment:

Perhaps the point about LISP was really analogous to a similar statement about assembly language. Sure it's possible to build arbitrary structures in either language, but is it natural, and does the language do some of your work for you? If your data structure needs to be an n-way tree with parent-pointers, then the natural lisp implementation for a node is probably something like ^ parent | --------- --------- --------- --------- ptr | | | --->| s1| --->| s2| ---> ...->| sn| / | | --|------ --------- --------- --------- \____/ with access functions for parent and each kind of son. (DEFUN FIFTH-SON (X) (CADDR (CADDDR X))) First, this is costly in terms of space (2*n+2 pointers where n+1 would do) and access time (FIFTH-SON needs all that extra list-walking); it would be much nicer to have hunks or arrays. Second, it makes nonstructured access possible, hence makes bugs easy (for example, the language does not enforce the programmer's intent that each node have exactly n sons, and the parent pointer requires rplaca, which opens the door to lots of potential bugs).

Personally, I disagree with Mark about the desirability of LISP. But then, I like assembly language too, and think they are very similar in flavor. It's a matter of taste, but I can certainly see his point.

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And now, on to the real point of my message. Does anyone know of an editor on Tops-20 that makes it easy to draw "box and arrow" diagrams like the above? I spent about 10 minutes using the ITS Emacs PICTURE library, and was very unhappy with it. Maybe I'll write an Emacs macro package, but in general it makes me realize that I'm fighting Emacs when I try to do something like the above; the teco primitives seem much better designed for editing text than for arbitrary pictures.

I don't even know exactly what user interface I would want in my "picture editor", given the constraints of character mode terminals, and no mouse. Certainly not something like SIL (which is also quite hard to use), but ...

Can anyone give me pointers to human factors research on picture editors? -------

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