Comments on: Does Anyone Like Electric Indentation?

By: Jared

Jared — Tue, 10 Feb 2009 07:49:14 +0000

@phil – Yes, part of my point was that if you’re electric indenting it better be possible to configure the indent so it is correct first time. Thanks for the pointer to the patch, I’ll take a look. (and why is electric indent better for you than indenting after carriage return?)

@martin – thanks, that clarifies what you were saying, and yes I see why it would be good for a certain set of programmers.

@snogglethorpe – your second and third paragraphs neatly sum up what I meant by electric indent interacting particularly badly with js2.el. And now I think about it, perhaps it could be useful for closing braces/brackets/etc. and I was (am) getting hung up on electric indent on quotes. Thanks for the input.

By: snogglethorpe

snogglethorpe — Tue, 10 Feb 2009 05:00:16 +0000

I can take or leave electric indentation — I find it can be nice in languages like C where often the indentation changes due to a line’s contents, and I don’t really want to add a new line afterwards.

However, I do feel strongly that a language mode should do correct indentation, without stupid workarounds like “oh just keep hitting TAB until it looks right”.

In this case, the thing that is broken is _not_ electric indentation, but the indenter. Maybe it’s a non-trivial problem for some languages (it seems vaguely odd that javascript would be one of them, but who knows…), and maybe yegge’s not up to solving it, but that doesn’t change the fact that it’s broken.

There are obviously languages like python which are incompatible with automatic indendation, but that’s a problem peculiar to such odd languages.

Of course, some people may simply dislike electric indentation — that’s fine, but it’s a personal preference, it doesn’t discount the fact that other people _do_ like it.

By: Martin

Martin — Mon, 09 Feb 2009 22:43:12 +0000

Sorry, my reply was confused in the middle…here’s what I meant to say:

1) automatic, immediate code formatting (this is more than electric indentation or perhaps is electric indentation where every character is electric) can be useful in some domain-specific language cases, or some beginning-programming-language cases (this is what I meant by my first paragraph)

2) I suppose the electric indentation you speak of wouldn’t be *too* much more confusing to a beginning programmer than post-return indenting, though I have no emplirical basis for this supposition (this is what I meant by “I think VB’s electric-indentation is perfectly matched to its user base”)

3) I don’t personally like electric indentation except perhaps in some DSLs.

So I think I’m agreeing with your (implied) premise that you can’t see electric indentation’s benefit to you (personally), and answering your explicit question (“what is [as in, can be] useful about electric indentation”).

By: Phil

Phil — Mon, 09 Feb 2009 22:01:05 +0000

In general I love electric-indentation if it can be assumed to do the right thing without any extra help. But js2-mode’s default indentation is infuriating. It was almost enough to make me ditch the mode entirely. Luckily I found a fix:

http://github.com/technomancy/emacs-starter-kit/blob/fe721654bd21825d36bace0f46a79271c5769cc1/starter-kit-js.el#L36

(I believe this was from a rejected (arg!) patch to js-2 from the tracker.)

By: Jared

Jared — Mon, 09 Feb 2009 20:40:47 +0000

Hi Martin,

I didn’t think about protecting (more experienced programmers from) beginning programmers, that is a good point. However, I still don’t see why adding an indent after a carriage return wouldn’t be sufficient. Or alternatively, if you really want to force a particular indentation on people, why not make every keystroke cause a re-indent?

Thanks

By: Martin

Martin — Mon, 09 Feb 2009 13:22:55 +0000

Nope, don’t like it. I think automatic, enforced code formatting has great value for beginning programmers or maintainers-who-are-not-primarily-programmers, because it lets them a) immediately see when their code’s AST does not match their expectation, since that case almost always occurs when they make a mistake (as opposed to when an experienced programmer might intentionally violate an indentation style for a very good reason); and b) it allows them to ignore the maintenance-of indentation (have you seen bad/new/non-programmers’ indentation?? It’s usually incredibly offensive).

I think VB’s electric-indentation is perfectly matched to its user base, and I’ve seen some domain-specific “IDE”s that do this to great effect.

So in this context I think you should decide whether you want non-serious programmers to use your environment for programming; if so, definitely enforce electric-indentation. If not, forget it.