Adding Section on Boxed Enums #116
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| @@ -322,6 +323,25 @@ typedef NS_ENUM(NSInteger, NYTAdRequestState) { | |||
| }; | |||
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| ## Boxing Enumerated Types | |||
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| Althought `enum`s are integral values, they cannot be directly used as [boxed literals](http://clang.llvm.org/docs/ObjectiveCLiterals.html#boxed-enums). So when creating a dictionary using `enum`s, they should be written as boxed literals instead of their corresponding `NSNumber` expression. | |||
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I would write the second sentence…
When boxing
enums (for example, when using them in a Cocoa collection) they should be boxed asNSNumbers using the shorthand@()literal expression, not as the[NSNumber numberWith…:]methods.This eliminates the need to look up the underlying type of the enum in order to box it correctly.
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I think "integral" isn't the right word. I would say "integer".
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I’d beg to differ. Integral makes sense in this context:
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I don't feel strongly either way, except to note that an enum could be backed by a type which isn't strictly speaking an integer in C.
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Ok, my dictionary fail
| @@ -322,6 +323,27 @@ typedef NS_ENUM(NSInteger, NYTAdRequestState) { | |||
| }; | |||
| ``` | |||
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| ## Boxing Enumerated Types | |||
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| Although `enum`s are integral values, they cannot be directly used as [boxed literals](http://clang.llvm.org/docs/ObjectiveCLiterals.html#boxed-enums). When boxing `enum`s (for example when using them in a Cocoa collection) they should be boxed as `NSNumber`s using the shorthand `@()` literal expression, not as the [NSNumber numberWith...:]` methods. | |||
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…, not as the [NSNumber numberWith...:]` methods.
You're missing the backtick before "[NSNumber" here.
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| **For example:** | ||
| ```objc | ||
| typedef NS_ENUM(NSInteger, NYTDaysOfTheWeek) { |
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IIRC, for proper integration with Swift the name of the enum and the values should share the same prefix. Such as:
typedef NS_ENUM(NSInteger, NYTWeekday) {
NYTWeekdayMonday = 0,
NYTWeekdayTuesday
}; There was a problem hiding this comment.
@mattbischoff not familiar with the Swift integration issue you're bringing up, could you point me in a direction regarding that?
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Thinking about this more, I’m not sure it belongs in the style guide. It doesn’t really cover any new ground stylistically. What do you all think? |
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I believe that by, "they cannot be directly used as boxed literals," @spacedrabbit is referencing Clang's (vaguely stated) decision to enforce Considering boxed literals— |
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What’s the status of this request? |
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I think this suggestion is subsumed by Literals and enforced by Clang. I would not merge this PR. Anybody else? |
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Makes sense to me. |
Creating PR for issue: #93 to explain the proposal. Let me know if this is worth explicitly mentioning/adding in or if this needs syntax changes.
closes #93