Indentation for single-statement bodies inside "for", "while", and "if"

[dwadden]

Hi,

The following code is auto-indented in Atom:

  if (x == 0)
  y = 0;
  else 
  y = 1;

If you give a one-line statement after a for, while, or if (or else), it would be cool if the auto indent did the right thing:

  if (x == 0)
    y = 0;
  else 
    y = 1;

Right now, you've got to use braces to get the correct indentation.

Was it decided to do things this way, or is this something you'd like changed? If so, I'm happy to try to fix it. I assume it requires editing the c.cson grammar file?

Dave

[thomasjo]

If you are able to implement this without breaking any existing functionality, that'd be great. I don't think this is currently possible, but I've not attempted it. You're going to have to change the indentation pattern options in settings/language-c.cson.

Do note that you're likely going to have to handle the scenario with braced one line blocks where the brace is not on the same line. In other words the change should not break this scenario

if (true)
{
  // ...
}

We do not want the first brace there to be indented, only lines subsequent the brace.

[dwadden]

OK, I'll give it a try.
Are there tests I should run to see if I've broken something, or should I just try some examples in the editor and see if they come out as expected?

[winstliu]

@dwadden if you're up to the challenge you can try creating specs that test for indentation: see https://github.com/atom/language-javascript/blob/master/spec/javascript-spec.coffee#L901 for an example.

[dwadden]

After taking a look at settings/language-c.cson, I now understand why this is tricky!
Increasing the indent pattern is fine, but decreasing it after a single-line loop body, using only regular expressions, would require a lookbehind regexp.

I know Javascript doesn't do lookbehinds. Atom seems to have them for a fixed number of characters back, but not an arbitrary number (I tried adding a simple lookbehind to language-c.cson, and it worked). Side question: what flavor of regex is Atom using? I had assumed Javascript?

So, unless I'm missing something, @thomasjo I agree this isn't a quick fix, you'd need more than regular expressions to do it. Maybe a separate package. I'd need to know more about how Atom does indentation. Can you point me in the right direction and I'll see if it looks like something I could actually tackle?

[winstliu]

@dwadden Atom uses Onigurama for parsing regex: http://oniguruma.rubyforge.org/oniguruma/files/Syntax_txt.html

[t1mg]

Any update on this issue, or any suggestions on what packages to use for C/C++ development with Atom that provides proper auto indentation?

[Aerijo]

@t1mg you may want to subscribe to this PR and try out the associated package.

[t1mg]

@Aerijo thanks that looks promising. Apparently, it doesn't fix this single-statement body problem though, at least not for me (upgraded my atom to 1.32.2 and used sane-indentation 1.0.6, tested in new cpp file).

[SabirKhanek]

is there any package to auto indent syntax in atom for C++ ide.