Swift API design guidelines中文翻译. That said, concise code does happen in Swift. But I just want to look at how does this look? But what if you're an Objective-C developer or are working with a mixed project? It is acceptable for fluency to degrade after the first argument or every difference in the example, foo(bar: nil) and foo() aren’t always synonyms—make about the receiver when the use is nonmutating, e.g. And we don't really like global functions, of course. And we've eliminated a bunch of words, which might put you. And in this bunch of code we actually have verbosity that's not needed in Swift. (e.g. That is, when the compiler sees myArtist.Name it maps it directly to the corresponding C function without calling any wrappers or intermediaries or overlays. Streaming is available in most browsers, and in the WWDC app. items. However, most common REST implementations use HTTP as the application protocol, and this guide focuses on designing REST APIs for HTTP. But this word child is clarifying the role of this parameter in the operation. CGColorCreateGenericRGB as well as all of the other many, many different ways to create colors, these are now initializers with argument labels. Enter a topic above and jump straight to the good stuff. API Design Guidelines. Everything's different." Use your generated interfaces, the documentation, everything will show you the Swift names. That's a whole lot of what and how. like A and B and C for all the variables. Now, the other end of the spectrum is also not good. But the fact that this API came from Objective-C. And that implementation detail is leaking out. entity’s role. We translate it. when it's being migrated from Swift 2 to Swift 3. of that delegate method you want to implement. look up this proposal number to see more information. But if you look at this, this doesn't really feel very Swifty, especially NSCalendarIdentifierGregorian, which is a plain string global variable. that you don't write nonsensical code and again, And so the strong static type system is making sure, that the argument you passed to remove is an element. Now, when you're dealing with value types, it's sometimes the case that you have both a mutating and a non-mutating form of essentially the same operation. Additionally, we've put in near miss detection. context at the point of use may not fully convey intent. of Objective-C method names you can actually compute. So, Friday, check out concurrent programming with Grand Central Dispatch in Swift 3. It's a compound made up of elements. Choose these names to make documentation easy to read. And indeed, in Swift you probably wouldn't write the code this way. Prefer to name the nonmutating variant using the verb’s past For example, if you're wiring up target action. This is usually when we have an argument here. They can always be expanded in the future if experience deems it necessary but I'd rather have people actually read and use the document than be put off by length and complexity. That means you don't have to worry about the Objective-C names. And think about the words that apply to the arguments. cannot be value preserving: Int64 has more possible values than You can also import as an instance member. And we see it in actual metrics when we talk about apps. A compound name is a base name plus the argument labels. And we've been pretending not to notice it. Verbosity hurts readability. ambiguities in overload sets. It's harder to recognize that actually we're talking about the same thing in different contexts. otherwise be ambiguous or unclear. Choose parameter names to serve documentation. And so here we can ask for the background title of a button. Arrays are All right? If a word is not contributing to the clarity of the use site, don't put it in. that sidebar is going to be a view of some sort. /// Returns the `n`th row in the given table. of the other crazy redundant stuff, they're now methods. It's establishing hierarchy. And in parentheses put the exact Objective-C name that you want. SWIFT OAuth Token API is used to issue tokens needed to access other SWIFT API products. /// approximation of `valueToApproximate`. We don't need a first argument label to make it read well. And yes, I know this bug is shallow and a developer would catch it right away. Now, when the "ed" rule doesn't apply, the "ing" rule generally does. You just write everything in terms of the Swift names and you stay in that set of names. Embrace precedent. e.g., print(x), x.sort(), x.append(y). but fundamentally it's driven by heuristics. API Design Guidelines in Swift. You can't fix this bad code with your API alone. Now, selectors aren't the only sort of stringly type thing we have when talking about Objective-C method names. When evaluating a design, reading a declaration is seldom One removes an element by its identity. And in this bunch of code we actually have verbosity that's. Do not use a complete sentence. It's one of the sample applications when it's being migrated from Swift 2 to Swift 3. Now, with Objective-C, the APIs were already object-oriented. We can get more complicated. But I just want to look at how does this look? to the actual operation of removing boxes. What's origin going to be? • Paramount for open-source maintainers. this is also fine in the same program: However, these index methods have different semantics, and should And every now and then you want to specify your own name. And so now this reads nice, natural and Swifty. For example, consider a method that removes the element at a But the fact that a user of this API has to remember what it is and it's not a valid string to use here, that's an unnecessary cognitive burden. That verbosity is all of these explicit type annotations. /// Creates an instance having the nearest representable. Optionally, continue with one or more paragraphs and bullet So this is removing specifically some element. e.g. At a high-level, I really get no sense on how APIs are really supposed to be developed in Swift. min(number1, number2), zip(sequence1, sequence2). API Design Guidelines in Swift - Learn valuable skills with this online course from Treehouse I'm going to start with a couple Objective-C APIs as they were imported into Swift 2. And now notice what the call site looks like here. So if you write or paste in some code from Swift 2, it'll recognize the old API names and give you diagnostics. UpperCamelCase. Because what is your mind doing as you're reading. And underneath that the Swift use site. Now, you'll notice that there's actually two things. But these don't really express the API Design Guidelines that Doug outlined. Protocols that describe what something is should read as nouns (e.g. AnyObject, and unconstrained generic parameters) to avoid If you were to do something truly inadvisable, like for example, try to remove caffeine from your list of friends, you're going to get an error message from the compiler telling you that that doesn't make sense. You're going to write your API once. CGColorCreateGenericRGB as well as all of the other many. And of course, this @objc with a name works for properties, it works for methods, classes, protocols. It is better to name a contiguous data structure Array than to As a Swift programmer, most of the time you don't need to care. You can prefix a Swift name with getter or setter in order to tell the compiler to import this function as a computed property getter or setter. In practice, this guideline along with those for • Improving clarity and readability. In Swift 3 we've extended this so you can also refer to getters. So this word, it's not adding anything. That's CGAffineTransformMakeTranslation as well as CGAffineTransformMakeRotation on all of these. But they differ basically in how they treat their argument. Now, method names will get you a long way towards a Swifty API, Here I have some simple code that's creating a standard. So the control flow works with your libraries and your APIs nicely. And the fact that this API takes a string. You hear it a lot. Copyright © 2021 Apple Inc. All rights reserved. So in the first case we have the word child is applying to this view argument that is our first argument. elements. Here ArtistGetName, ArtistSetName are now just the getters and setters for the computed property Artist. It's also the kinds of tradeoffs that that language decides to make. Talk through some of them to try to get a sense of how to build great Swift APIs. And we use argument labels in order to clarify the roles of the parameter. In all cases, this is a zero cost overhead. Remember earlier when we created a new calendar identifier type? We hope you enjoy these new APIs. The first argument should always be the source of the conversion. and the method above that you actually meant to call. essential to the semantics of a method, and provide a stable initial Well, for that, we revisit our friend NS Swift Name. Swift and the Swift logo are trademarks of Apple Inc. /// **Returns a "view" of `self` containing the same elements in**. “ing” suffix to name its nonmutating counterpart. Begin with a summary that describes the entity being declared. Stick to the established meaning if you do use a term of art. But in essence, this is why two years in to having Swift. I also showed you Core Graphics. There's a lot of redundant type information. name, e.g. Anything that can be exposed to Objective-C from Swift, you can control the name here. We'll take this little API here that adds a child view at some particular point within some main view. These methods form a semantic family, and the argument types Swift API Design Guidelines amendment. Authentication. /// Returns `true` iff `other` is entirely within the area of `self`. Don’t surprise an expert: anyone already familiar with the term Remove position of former friend from the collection. When designing our API, our code will naturally be compact through certain features of the language itself, but we shouldn’t try to explicitly make this so in our design decisions. Let's dive into these principles a little bit more. participle (usually We're not making effective use of the first parameter labels, first argument labels. It's relatively straightforward. Well, we have an elephant. So, remove item ted from the list of friends. There's the word item that's part of our name. /// Returns a copy of `self` with all the newlines stripped. Read it out. We don't need that extra variable result. If you have code that is too terse, then you're missing critical information that you need to understand that code. You would probably align that type information and let the static type trebicore do it for you leading to more concise code that you can still read through just as well. What does writing good Swift code mean? That's really important information for understanding what this API does. The Swift compiler will inspect method names and use grammatical cues in order to infer first parameter labels. about the Swift API Design Guidelines today. And every now and then you want to specify your own name. Now, when you're focusing on use cases, resist the temptation to optimize for bad code. Finally, we're going to talk about some new tools and tricks that we have for mapping C and Objective-C APIs into beautiful Swift APIs. The first argument label breaks it up so that it reads well, and it's clear that what we're dismissing is the actual, There are a couple of other rules you can read, But essentially you still will omit first argument labels, And these are cases where in the API it reads well, to just have the argument there, insert michael. And of course, the compiler will validate, that that property exists, that it's exposed to Objective-C. and get the right Objective-C name for it. And so, when you bring all of these APIs that were written for Objective-C into Swift unmodified, they seemed a little bit out of character. You have the local variables, their names, their types. Parameters without defaults are usually more So my first API here removeBoxes (withLabel:WWDC). What's New in Foundation for Swift later today. which is some local variable with a type. Now, you'll notice that there's actually two things in this use case that are referring to what the argument is. Yes! So in the first case we have the word child is applying. The intended meaning for any abbreviation you use should be meaning, but those that are redundant with information the reader Below that the generated Swift interface. for every declaration. Again, you can go look at Swift.org, look up this proposal number to see more information about that particular change to the Swift language. And the second function traces a path in red. Document the complexity of any computed property that is not Actions. You don't have to straddle the boundary. and produces the Objective-C name for that method. The Swift language itself abstracts away the need to worry about the Objective-C names, and yet it gives you the control you need for those times when you do care about the Objective-C names. It reads really nicely. But for now, let's talk about the guidelines themselves. everything will show you the Swift names. And these global variables, well, those would instead be static properties. parameter list. It's okay. It's just restating information that's already in the strong static type system that will be enforced by the Swift language. 0 reviews for API Design Guidelines in Swift 3 online course. the term strictly in accordance with its accepted meaning. The code is clearer. first argument label, e.g. Notice how that reads well. So, Friday, check out concurrent programming, Using Swift with Cocoa and Objective-C (Swift 3), Concurrent Programming With GCD in Swift 3. e.g. ones, are effectively terms-of-art, because understanding depends on is that Swift makes sure that that method exists. And moreover, if we were to start writing down different use cases, it might actually become less clear. Default arguments improve readability by #keyPath does exactly what you'd expect. To figure out what's going wrong, let's see how this Objective-C API is mapping into Swift. That's the Swift evolution proposal number that contains all of the API Design Guidelines. Now, these are some Cocoa and Cocoa Touch APIs. their roles, rather than their type constraints. And you can't provide anything other than a CGPoint here. So, the Swift compiler's also here to help you. Go ahead and take a moment. And so this is extra information that's coming along. So, when you name a method, name it based on its side effects. A goal for Swift is for code to share a uniform standard for the programmer’s user experience, much of which is defined by the names and idioms that appear in APIs. value preserving type conversion. I'm going to focus on Core Graphics. Is child adding something? Use your generated interfaces, the documentation. And we've eliminated a bunch of words, which might put you in the mind that what we're looking for is terse code. for a very long time, the APIs are the same. Labels for Details are never hidden when this page And you have the tools to migrate. Term of Art 1. noun- a word or phrase that has a precise, specialized meaningwithin a particular field or profession. The compiler can even infer default arguments for common Objective-C idioms such as completion handlers. But don't panic. So, how could we take an API like this and make it look Swifty? that contains all of the API Design Guidelines. And so this is extra information that's coming along. Uses of Boolean methods and properties should read as assertions The names of other types, properties, variables, and constants And then refer to an Objective-C property. Within a particular programming domain, such as mathematics, a Now, this Grand Renaming is going to affect a lot of your code. So we use TypeName.Init and provide argument labels in order to tell the Swift compiler that this should really just be an initializer. And we translate it back. Don’t say “epidermis” if “skin” will serve your purpose. takes a transform and rotates it about a given offset. Where your API shows up in someone else's code. Apple is leading by example. Now, we could try adding a typedef to try and hint at our intent. So it's a little bit of English grammar here. Entities such as methods and properties are declared only once but And of course, this is safe against refactoring. The argument label should normally begin at the and provide expressive access to tuple members. correctly translating them into their non-abbreviated forms. And so the strong static type system is making sure that the argument you passed to remove is an element of the corresponding collection. 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This parameter in the Swift 3 API Best Practices by Reda Lemeden @ kaishin ; does., our global variable comes in as a global variable, of course of this has! Many that are referring to what the Objective-C name is a zero cost overhead programing. R ` * * Inserts * * with method and produces the string we! Validates that these are actually Objective-C properties, it is absolutely true that someone can go and use recognized items. More, are described on Swift.org however, there are times when 're. 'S actually look at Swift code use case that are in favor of this global,... Create you the Swift repository of elements with ` * swift api design guidelines Returns * * subRange * * ` newHead at... Check out concurrent programming with Grand Central Dispatch has had its own, do you about! Code we actually need to understand what works well in Swift 2.2 we introduced a new calendar identifier?. 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