[cfe-dev] clang-format behavior for Obj-C methods with block parameters

manuyavuz via cfe-dev cfe-dev at lists.llvm.org
Mon Dec 14 00:43:05 PST 2015


On 13 Dec 2015, at 20:15, Daniel Jasper <djasper at google.com <mailto:djasper at google.com>> wrote:

> 
> 
> On Sun, Dec 13, 2015 at 6:53 PM, Yavuz Nuzumlalı <manuyavuz at gmail.com <mailto:manuyavuz at gmail.com>> wrote:
> Thanks for the response Daniel,
> 
> Could you guide me on where can I look inside clang-format implementation to see how clang-format currently handles lambdas in other languages, so that I may try to implement the same functionality for Objective-C case?
> 
> Not really, it is all in ContinuationIndenter.cpp. However, this is among the most complex code of clang-format and giving you details on how to do this probably would take me longer than looking at this myself. If you still want to try and take a look, feel free. I am happy to answer any specific questions you might have.
>  
> 
> Besides that, I have one more question, which is somewhat related to topic.
> 
> When I try to use clang-format to format the following simple code:
> 
> - (void)asdf {
> 	[UIView animateasdfasdf:0 animations:^{ }];
> 	[UIView animations:^{ } done:YES];
> 	[UIView animations:^{ } completion:^{ }];
> 	[UIView testasdfasdfsd:YES animations:^{ } completion:^{ }];
> 	[UIView animations:^{ } tessd:YES completion:^{ }];
> }
> 
> Output is the following:
> 
> - (void)asdf {
>   [UIView animateasdfasdf:0
>                animations:^{
>                }];
>   [UIView animations:^{
>   }
>                 done:YES];
>   [UIView animations:^{
>   }
>       completion:^{
>       }];
>   [UIView testasdfasdfsd:YES
>       animations:^{
>       }
>       completion:^{
>       }];
>   [UIView animations:^{
>   }
>       tessd:YES
>       completion:^{
>       }];
> }
> 
> I think clang-format somehow decides to not use colon alignment but align using `ContinuationIndentWidth` where there are more than one block parameters.
> Is this an intended behavior? Seems like a bug to me.
> 
> It is intentional. Column alignment with more than one internal block doesn't really work. And this is also explicitly written in Google's style guide: https://google.github.io/styleguide/objcguide.xml#Blocks <https://google.github.io/styleguide/objcguide.xml#Blocks>
> 
> Independent of that some of you examples look like there are still other bugs in there.
> 
I carefully read the google style guide, and behavior about multiple inline blocks seems reasonable now. 
However, I still feel it's not fully consistent because of the third method call example above. 
I think that case should have something like the following format in order to be consistent across the code:

[UIView 
    animations:^{
    }
    completion:^{
    }];

Also there is another case in which formatting messes completely:

  [UIView animateWithDuration:123 delay:123 usingSpringWithDamping:123 initialSpringVelocity:123 options:123 animations:^{ } completion:^(BOOL finished){ }];

becomes this:

  [UIView animateWithDuration:123
      delay:123
      usingSpringWithDamping:123
      initialSpringVelocity:123
      options:123
      animations:^{
      }
      completion:^(BOOL finished){
      }];

Is this (cancelling colon alignment also for non-block parameters ) also intentional? 
If so, I understand that clang-format will apply standard `ContinuationIndentWidth` value whenever a method call includes more than one inline blocks.

I question this scenario too much because the above code is a frequent code block to animate views on screen, and having a consistent behavior is important in order to use clang-format’s automatic formatting without any hesitancy 

> PS : I'm using the default LLVM configuration for the above case.
>> On 13 Dec 2015, at 16:42, Daniel Jasper <djasper at google.com <>> wrote:
>> 
> 
>> Nope, this behavior isn't currently implemented. I agree that it might make sense, as it is similar to how clang-format treats lambdas at the end of several other parameters.
>> 
>> On Fri, Dec 11, 2015 at 4:08 PM, Yavuz Nuzumlalı <cfe-dev at lists.llvm.org <>> wrote:
>> Hi everyone,
>> 
>> I'm experiencing a problem with clang-format for my code.
>> 
>> I'm using ColumnLimit as 120. When I write some code like this:
>> 
>> [self testMethod:15 withBlock:^{
>> 	NSLog(@"asdfasdf");
>> 	NSLog(@"asdfasdf");
>> 	NSLog(@"asdfasdf");
>> 	NSLog(@"asdfasdf");
>> }];
>> 
>> This code would be converted to this by clang-format:
>> 
>> [self testMethod:15
>>        withBlock:^{
>> 	       NSLog(@"asdfasdf");
>> 	       NSLog(@"asdfasdf");
>> 	       NSLog(@"asdfasdf");
>> 	       NSLog(@"asdfasdf");
>> 	   }];
>> 
>> That seems wrong to me because the method call before block variable actually fits in width of 120. I guess this is because clang-format behaves above code as a single method call and assumes it as one line. But I really want to not split the method like this because it feels weird.
>> 
>> Is there a way to accomplish this with current system?
>> 
>> I put my configuration file as an attachment.
>> 
>> Best
>> 
>> 
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>> 
>> 
> 
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