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Aucbvax.4218 fa.editor-p utzoo!decvax!ucbvax!editor-people Sun Oct 4 21:16:38 1981 meta flames >From dlw@MIT-AI Sun Oct 4 21:14:49 1981 In response to your challenge, here are some thoughts about designing user interfaces for novices versus designing them for experts.

I think that we can and should design user interfaces suitable for everybody. Emacs does a pretty good job of this, although it could be better. Some people have said "having an editor with a lot of commands confuses novices". I disagree; I think that you can start out a beginner with a small subset of the commands and simply not mention the others. The only real problems are caused by the users's accidentally typing advanced commands that put them into modes where it is unclear how to escape; the interface could be improved to make it easier to get out of such modes, or there could be a beginner's switch that disables certain commands. (I understand that the latter is available through an Emacs library.)

Use of Control-N for "Next line" and Control-B for "Backward" and even Control-A for "beginning of line" are easy to learn. To learn these commands is a matter of a bit of rote memorization, somewhat aided by the choice of characters (B is for Backward). Since you get extremely quick and interactive feedback when you use the commands, the learning is reinforced strongly.

What makes it hard to advance in learning Emacs are the occasional inconsistencies and complexities. The command set is not as symmetrical as it could be. That Control-U is almost but not quite the same as giving a numeric argument of four is unnecessarily confusing; in fact, the philosophy behind Control-U, which sometimes works as a numeric argument and sometimes works as a random modifier, is not very good. This seems to be rooted in history (the TECMAC editor, one of the important fathers of Emacs, had this, too), and it could be fixed were there a complete redesign. In a redesigned command set, there might be more prefix characters, or a general re-think of how prefixes and modifiers work, intended to be more consistent and simple.

Coming up with a consistent user interface for the functionality of full Emacs is a time-consuming job. Emacs's present functionality was need-driven and it grew incrementally; naturally the user interface shows signs of history and growth, and is not as good as it could have been if the designers had had perfect foresight. However, it is important to note that it COULD be done better, and that the result would come close to the goal of being equally suited to novices and experts.

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