On Sat, Jun 18, 2016 at 4:50 PM, Michael Peternell via swift-evolution < [email protected]> wrote:
> > > Am 17.06.2016 um 07:45 schrieb Charlie Monroe via swift-evolution < > [email protected]>: > > > > Motivational example: > > > > var urlString = self.urlString > > if urlString.hasPrefix("//") { > > urlString = "http:" + urlString // urlString needs to be typed > twice > > } > > > > While there is currently an easy way to append string using +=, there is > no shortcut for prefixing a string. What I propose is adding a =+ operator > for prefixing the string: > > > > urlString =+ "http:" > > > > Would anyone else find it useful? > > No. What I would find useful though, is to recognize that addition is not > string concatenation. There is a strong convention in mathematics that the > "+" symbol should only be used for operations that are commutative. String > concatenation is not commutative. (There are more conventions regarding > "+", but all of them are respected by numbers, vectors, complex numbers, > quaternions, or matrices - just to name a few.) > > I would like to have a different operator for string concatenation. I don't see how this would measurably improve Swift code. IIUC, much of the problem with `+` and strings arises from implicit conversions that don't happen in Swift. It's not even possible to write a generic algorithm that accidentally confuses arithmetic `+` and string concatenation `+`, since you would have to retroactively conform strings and numeric types to a nonsensical protocol of your own making. > Maybe "~~" or "++"? Now that the prefix and postfix operators for numbers > ("++" and "--") are removed from Swift 3, "++" could be used for string > concatenation. > > -Michael > > _______________________________________________ > swift-evolution mailing list > [email protected] > https://lists.swift.org/mailman/listinfo/swift-evolution >
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