[swift-evolution] SE-0105: Removing Where Clauses from For-In Loops

[Charlie Monroe]

> On Jun 24, 2016, at 9:00 PM, Xiaodi Wu via swift-evolution <swift-evolution at swift.org> wrote:
> 
> On Fri, Jun 24, 2016 at 1:56 PM, Sean Heber <sean at fifthace.com <mailto:sean at fifthace.com>> wrote:
> > On Jun 24, 2016, at 1:30 PM, Xiaodi Wu via swift-evolution <swift-evolution at swift.org <mailto:swift-evolution at swift.org>> wrote:
> >
> > On Fri, Jun 24, 2016 at 6:37 AM, William Shipley <wjs at mac.com <mailto:wjs at mac.com>> wrote:
> > On Jun 23, 2016, at 11:04 PM, Xiaodi Wu <xiaodi.wu at gmail.com <mailto:xiaodi.wu at gmail.com>> wrote:
> >>
> >> Not a practitioner of 80-character line limits, I take it?
> >
> > I don’t understand why anyone wouldn’t just let Xcode do the wrapping for most cases. I’ll add newlines if I think it adds to clarity, but in general I don’t want to code like i’m still on a Wyse WY-50.
> >
> > Of course, to each their own style--I certainly wouldn't want Swift to force everyone to write lines of certain lengths. But 80-character lines is a common style, and I would say that a corollary of "to each their own" is that Swift's grammar should be usable and useful whether or not you adhere to such style choices.
> 
> I honestly don’t believe that this a common style in the Cocoa community.
> 
> We're talking about the Swift community here, and Swift stdlib would be a good starting point as to what is a common or at least accepted style; it uses 80-character lines.

While it does, it makes sense only for readability purposes of the documentation. For example, I see absolute no reason why to split https://github.com/apple/swift/blob/master/stdlib/public/core/StringBuffer.swift#L233 <https://github.com/apple/swift/blob/master/stdlib/public/core/StringBuffer.swift#L233> into two lines.

It makes the code less readable.

80-char style made sense in C, where everything is pretty much top-level. But given that you declare a class, within which you declare another class, within which you declare methods, the first level of the method indentation is at level 3, which given 4 spaces per tab gives you 12 characters already. Adding a few levels (for-cycle + an if statement within the for cycle) gives you 20 characters of just whitespace (1/4 of the allocated 80 chars per line).

Which is why I don't believe this code style is valid in a modern language. My personal guess is that it should be upped to e.g. 160 chars per line - that kind of makes sense. There is no particular reason other than historic why we're still using 80 chars per line.

>  
> I’m not a member of the “old guard” having only come into this world 10 years ago with the iPhone, but just take a look at this delegate method in Objective-C:
> 
> - (void)locationManager:(CLLocationManager *)manager rangingBeaconsDidFailForRegion:(CLBeaconRegion *)region withError:(NSError *)error;
> 
> That’s well over 80 characters all by itself. This fits on my screen in a single line - and I work on a 15” MBP with room for my dock always visible on the side along with Xcode’s sidebar open! On a typical desktop-sized screen, 80-col lines must be comically short.
> 
> I don’t know why it should be assumed that people are adhering to a so-called standard that dates back to terminal screens that didn’t have color.
> 
> 
> > If the chief advantage of `where` is that it (quoting someone above) allows one to "understand as much as possible about the control flow of the loop from a single line of code," then we ought perhaps to question its appropriateness when the majority of its benefits [by which I mean, based on your examples and Sean's, more than half of the instances in which it is used] cannot be realized in a very common coding style.
> 
> Again, I dispute the idea (having no data but my own :P) that 80-col limits are common in this community.
> 
> l8r
> Sean
> 
> 
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