On Tue, Nov 27, 2012 at 3:42 PM, Daniel James <dnljms@gmail.com> wrote:
On 26 November 2012 14:13, Andrey Semashev <andrey.semashev@gmail.com> wrote:
On Mon, Nov 26, 2012 at 5:48 PM, Daniel James <dnljms@gmail.com> wrote:
A string isn't the same thing as a range of characters.
Why?
Strings are one of the most important types in programming, and they're usually handled differently from ranges. A string is essentially a thing, not a sequence of things. Using a range confuses the string's representation for its type.
I guess, that depends on the perspective. I imagine strings as sequences of characters and typically my string processing code is similar to that of other ranges. You just have a certain additional knowledge of its elements' nature.
A range of characters can be binary data, or a collection of small integers, I don't want them coming anywhere near string handling code, and in C++ the type system is the best way to handle that. It should be easy to have distinct overloads for strings and ranges.
Probably, although I can hardly imagine overloads of a single method that have different semantics for a string and a range of characters. This would likely be the sign of a poor interface. OTOH, interfaces that just want to accept "some string" are common.
That's why I suggested a customisation mechanism. Something would allow you to indicate that a third party type is a string and, if necessary, how to get a string_ref from it. Perhaps an ADL hook, or a template class that is specialized for strings, or something else entirely.
That would mean that the range is limited to strings only.
Not at all, you could still explicitly convert to a string_ref.
I would have been happy with what you suggest if I was sure this customization mechanism is going to be adopted by third-party strings. I have a good faith in begin()/end() adoption, at least because this mechanism is used by the language core (range-based for) and it is logical for strings to support it. I am not so sure for a type trait or some other mechanism that detect string types.