[swift-evolution] Strings in Swift 4

[Jeremy Pereira]

> On 20 Jan 2017, at 10:30, Maxim Veksler via swift-evolution <swift-evolution at swift.org> wrote:
> 
> One ask - make string interpolation great again?
> 
> Taking from examples supplied at https://github.com/apple/swift/blob/master/docs/StringManifesto.md#string-interpolation
> 
> "Column 1: \(n.format(radix:16, width:8)) *** \(message)"
> 
> Why not use:
> 
> "Column 1: ${n.format(radix:16, width:8)} *** $message"
> 
> Which for my preference makes the syntax feel more readable, avoids the "double ))" in terms of string interpolation termination and function termination points. And if that's not enough brings the "feel" of the language to be scriptable in nature common in bash, sh, zsh and co.. scripting interpreters and has been adopted as part of ES6 interpolation syntax[1]. 
> 

This idea came up once before on Swift Evo. The arguments against are:

1. Swift already has an “escape” character for inserting non literal stuff into strings - the “\” character. Either you have two - increasing complexity for both the developer and the Swift compiler’s tokeniser - or you have to change everything that uses “\” to use $ e.g. $t $n instead of \t \n.  

2. The dollar sign is a disastrous symbol to use for an special character, especially in the USA where it is commonly used to signify the local currency. Yes, I know it is used for interpolation in Perl, Shell and Javascript and others,  but “this other language I like does X, therefore Swift should do X” is not a good argument.

3. There is already quite a lot of code that uses \( … ) for interpolation, this would be a massive breaking change.