Fix indent_continue not indenting nested statements

[dbartolini]

Allows indent_continue to increment the indentation level in nested statements.
The LANG_OC check is to ensure previous behavior since this could break Objective-C code in strange ways I will not be able to fix properly at the moment.

This fixes all indenting problems in my C++ codebase without introducing regressions, especially in code inside lambdas, but feedback and broader testing is very much appreciated.

Fixes #3752.

[micheleCTDEAdmin]

Ciao Daniele,
I tested the PR over 3200 files and it does fix a lot of mis-indentation.
On the other hand I also spotted few regressions, with some code being indented too much. The regressions are similar in concept to the modified "expected" cpp files in this PR, where you can see extra indentation added.
If you could find a way to fix this PR so that the extra indentation is not present, it would be a great PR to merge.

[dbartolini]

Assuming the regressions are similar to the one in tests/expected/cpp/31593-sf593.cpp: should indent_continue avoid incrementing the indentation when "nested statements are on the same line"?

The other modified "expected" .cpp files should not contain more indentation than necessary I think, could you confirm that?

[micheleCTDEAdmin]

Yes, the regression I observed are similar to the one in tests/expected/cpp/31593-sf593.cpp. If you need, I can provide some examples.

Regarding the other modified tests, it could probably be a subjective thing. For example tests/expected/cpp/60055-issue_3116.cpp, the body of the lambda function is intended twice compared to the B function. While technically there are three levels of indentation (A -> B -> lambda body) and so it would explain the extra indentation, on the other hand it does look a bit awkward. What's your take on it?

[dbartolini]

Yes, the regression I observed are similar to the one in tests/expected/cpp/31593-sf593.cpp. If you need, I can provide some examples.

It would be helpful, thanks!

Regarding the other modified tests, it could probably be a subjective thing. For example tests/expected/cpp/60055-issue_3116.cpp, the body of the lambda function is intended twice compared to the B function. While technically there are three levels of indentation (A -> B -> lambda body) and so it would explain the extra indentation, on the other hand it does look a bit awkward.

It does look awkward indeed, but it is consistent with how lambdas are indented normally. In this case, the ) of B is on the same line with the } of its lambda parameter, and that is what makes it look weird, I think. Had the closing parentheses been on its own line, it would have looked nice and correct:

A(
    B([] (const std::string &s) -> bool {
            s = "hello";
            return true;
        }
    ), 1
);

Moreover, if you add extra parameters to B, with this PR you will get something like this, which I think it is correct:

A(
    B(foo,
        bar,
        [] (const std::string &s) -> bool {
            s = "hello";
            return true;
        }
    ), 1
);

Compare it with the current behavior; doesn't this look even weirder with those parameters squashed to B()'s level?

A(
    B(foo,
    bar,
    [] (const std::string &s) -> bool {
        s = "hello";
        return true;
    }
    ), 1
);

Like you said, it may be a subjective thing, and another option to adjust for personal preferences would be needed I guess.

[micheleCTDE]

I have attached an example showing some regressions, including the config used to test it. Note that I use negative values for indent_continue.

Re lambda indentation, I see the point in your comment. Also there is an interesting idea proposed in issue #3815, so the solution may be to merge this PR (once the other regressions are fixed) and then add an option as proposed by @PoeticPete.

pr_3816.zip