Hacker News Reader

Comment by seanalltogether | Hacker News Reader

What i don't really see in the docs is how to calls to objective-c methods are sorted out. For instance, if I have an objective-c class with a method

    -(void)addNumber:(NSNumber*)num withString:(NSString*)str;

How is this called in swift? Is it

    myobj.addNumber(42, withString:"Hello World")?

View on HN

  myobj.addNumber(42, withString:"Hello World")

edit: I see you removed your equals - your guess is now correct :)

for more details, see this link on apple's docs (may change)

https://developer.apple.com/library/prerelease/ios/documenta...

There is a section in the docs about it. Similar to what you propose. https://developer.apple.com/library/prerelease/ios/documenta...

    UIColor *color = [UIColor colorWithRed:0.5 green:0.0 blue:0.5 alpha:1.0];


    let color = UIColor(red: 0.5, green: 0.0, blue: 0.5, alpha: 1.0)

Wow, this just brings up more questions, is the compiler removing the "colorWith" semantics or do you write your own translator?

I suspect they wrote a new init function specifically for Swift (as an extension), but I could be wrong.

They have a concept of implicit/explicit "external parameter names".

The docs definitely indicate that some magic is occurring but they don't say exactly how. Perhaps If the first parameter contains the word "With"?

They do explicitly state that initializers will get "init" and "initWith" stripped off and whatever follows becomes the first parameter. The fact that "colorWithRed" is translated to "red" might indicate that it is looking for the keyword "With"

In AppleScriptObjC, Objective-C methods are converted from

    -(void)addNumber:(NSNumber)num withString:(NSString)str;

    addNumber_withString(num, str)

Swift could be different, though.

The whole function name is addNumber:withString:

so if it has to be something, it might be myobj.addNumberWithString(42, "Hello world")

Reply on news.ycombinator.com