Swift - 没有得到println中变量名的建议

Question

var firstLoop = 0
for i in 2..<6 {
    firstLoop += i
}
println(firstLoop)
println("\(firstLoop)")
println("\(firstLoop.description)")

Here i am printing the firstLoop variable. But in the first println , when I type the word firstLoop , it is not showing any suggestions, while in next two println as I type firstLoop it is showing suggestions. Here can any one explain to me why it is not showing the suggestion in first println ? And can I use this format to print the variable? Is that a correct way to print the varible?

Answer 1

That seems to be a bug. Have you tried pressing the esc-key to show code suggestions? For the second part of your question: In this case it doesn't really matter which println you use. The last two are essentially the same, since Swift automatically calls the description method of an object when you print it. However, for clarity's sake I would use this

println("firstLoop: \(firstLoop)")

to print the variable, just so you don't confuse it with another one you might print earlier or later in your code.

Answer 2

Yes, it is legal and correct; there is absolutely no need to perform string interpolation merely to println something (and indeed, string interpolation merely does the same thing println itself does, namely, calls the description of a Printable). You've found an Xcode code completion bug. This has nothing to do with iOS or Swift except tangentially; it's an Xcode problem.