On Sat, Jan 22, 2011 at 3:18 AM, Dave Abrahams <dave@boostpro.com> wrote:
At Sat, 22 Jan 2011 01:56:36 +0800, Dean Michael Berris wrote:
No changing arbitrary content in the string. Concatenation is a process of creating new strings.
But you're allowing assignment. That's not acting "as if it's const, with no way to modify the string"
Unless you frame assignment in terms of a "move". x = "This is the original"; x = "Not anymore"; What's happening here is that you're really making x refer to a different string. In essence, x is what you might call a proxy. You can change what the proxy refers to, but what it refers to you cannot change -- if that makes any sense. If you're reading or dealing with x, basically you're dealing with the proxy. So when you're doing concatenation, what's really happening is you're building a new string and making the proxy refer to that new string. x = "Hello,"; x = x ^ " World!"; Note this doesn't violate the value semantics of the object much like how pointers provide value semantics (because they are values). -- Dean Michael Berris about.me/deanberris