Can you use string/character literals within Swift string interpolation?

Question

Is it possible to use a String/Character literal within string interpolation in Swift?

The language reference says:

The expression you write inside parentheses within an interpolated string cannot contain an unescaped double quote (") ...

That's a little fuzzy to me, since it seems to deliberately leave the loophole of escaped double quotes.

If I try:

println( "Output: \(repeat("H",20))" );

func repeat( char:Character, times:Int ) -> String {
    var output:String = "";
    for index in 1...times {
        output += char;
    }
    return output;
}

I get "Expected ',' separator".

Similarly, if I do the same thing, but escape the quotes, still no dice:

println( "Output: \(repeat(\"H\",20))" );

I suspect it's just not possible, and to be honest, no big deal -- I haven't found any example that I can't easily solve by doing a little work before the string interpolation, I guess I'm just looking for confirmation that it's just not possible.

println("Output: " + repeat("H", 20) + "");, maybe? the last "" would not have been necessary to be added. — holex
– holex, Commented Aug 11, 2014 at 15:39
Sure, that totally works -- but it's not string interpolation, it's just string concatenation. — Geoffrey Wiseman
– Geoffrey Wiseman, Commented Aug 12, 2014 at 17:53
Unfortunately I don't have a solution to your problem but when you use for in loop -> when your not using index simply do for _ in 1...times — borchero
– borchero, Commented Dec 18, 2014 at 21:24
possible duplicate of escape dictionary key double quotes when doing println dictionary item in Swift — Mixaz
– Mixaz, Commented Aug 27, 2015 at 22:19

Geoffrey Wiseman · Accepted Answer · 2015-09-25 03:13:52Z

3

It can be done starting in Swift 2.1: http://www.russbishop.net/swift-2-1

Prior to that, it wasn't possible.

answered Sep 25, 2015 at 3:13

Geoffrey Wiseman

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Comments

user1671097 · Accepted Answer · 2014-09-05 07:16:13Z

0

I hope it's:

let strfunc = repeat("H",20) as string
println( "Output: \(strfunc)" );

answered Sep 5, 2014 at 7:16

user1671097

1 Comment

Geoffrey Wiseman Over a year ago

Yeah, again, a perfectly fine solution to the problem I don't have. ;) There are lots of ways to get a repeated character into a string with or without interpolation. What I was really trying to verify is that there is no way to use a string literal within a Swift string interpolation expression. There doesn't seem to be.

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