On Wednesday, August 22, 2012 19:52:10 Sean Kelly wrote: > I'm clearly missing something. ASCII and UTF-8 are compatible. What's > stopping you from just processing these as if they were UTF-8 strings?
Range-based functions will treat arrays of char or wchar as forward ranges of dchar. Because of the variable length of their code points, they aren't considered to have length, be random access, or have slicing and will not generally work with range-based functions which require any of those operations (though some range-based functions do specialize on strings and use those operations where they can based on proper understanding of unicode). On the other hand, if you have a string that specifically holds ASCII and you know that it only holds ASCII, you know that you can safely use length, random access, and slicing as if each code unit were a full code point. But the range-based functions don't know that your string is guaranteed to be ASCII- only, so they continue to treat it as a range of dchar rather than char. The solution is to either create a wrapper range whose element type is char or to cast the char[] to ubyte[]. And Bearophile wants such a wrapper range to be added to Phobos. - Jonathan M Davis
