How to allow 2-line if statements using clang-format

Question

I am working on setting up a style format check for a large library. Currently, our team styleguide prefers that instead of one line if statements, we use a "2 line" statement, which looks like this

if(statementIsTrue)
{ printf("True"); }
else
{
 anExampleBlock = true;
 elsestatement.function();
}

Note how the if block is partially indented to 2 spaces, to line up with the else statement. The style's indentation is 3 spaces. In addition, there are 2 spaces between the semicolon and the close brace for symmetry purposes.

Other thing to note about the style. braces always go on a new line. That is the intention behind the above. For all if statements, functions, classes, etc. the opening brace goes on a new line.

How can we adjust clang-format to perform this task?

EDIT: More examples of blocks

/**
 * This is just example code for formatting, not meant to be useful code
 */
bool testFunction(int largeNumber, int randomNumber)
{
 for (int j = 0; j < largeNumber; j++)
 {
 if (j == randomNumber)
 { return true; }
 else
 { print("not found"); }
 }
}
int main()
{
 //Three space indentation (tab characters should not be used anywhere)
 //Single space should exist between if, else if, for, while, etc. and (...)
 if (testFunction(testParm1, testParm2))
 {
 print("Hello");
 return true;
 }
}

• Retired Ninja: My advice is change your style guide. That is very hard to read. Make the if like the else.
• Ska: Posted another example to clarify. I understand this is not a common style, but this is a very old library, that would not be easy to change style for. Looking for a solution to actually format this
• cigien: If you use clang-format you can write your own rules, relatively easily.
• JohnFilleau: Oh my god. OP is asking how to do a specific, objective thing in a common tool. Everyone is saying in comments, "You do it by doing it." How do they do it? This question should never have been closed. It's not opinion based. It's a clear question with an objective answer.
• Ted Lyngmo: @JohnFilleau When I voted to close this, the question was "Is there any formatter that can handle this? And what would the configuration look like?" - but I'll vote to reopen now that it's specifically about clang-format.

Answer 1

I think, if you edit your .clang-format file in your project repo with the following settings, it should work.

Please note - I haven't tested this, but reading the documentation, I felt this would be suitable.

BreakBeforeBraces:Allman,
AllowShortBlocksOnASingleLine: Always,
AllowShortIfStatementsOnASingleLine: WithoutElse

If this doesn't work, experiment with possible options for these fields available at Clang-format style options

Hope this helps!

Here is an online tool which I found where you could play around with your code trying out various options: clang-format configurator

Sample experiment with your code snippet

• Ska: Hi, this does not work. The settings you provided result in this ``` if (_c) { anotherVariable = nullptr; } if (_a) { anotherVariable = "baz"; } else { anotherVariable = "bar"; } ```
• Ska: The formatting is not working, but the blocks end up being 4 lines long, instead of the intended 2
• Honey Sukesan: The expected output is not clear from the original question. Please post snippet of how your current code look like and how you want it to be displayed.
• Honey Sukesan: Added some more information in the my response. Hope it helps.
• Ska: This does not help. Notice how your output is different than my expected output