On Wednesday 03 August 2011 08:29:09 Jacob Carlborg wrote: > On 2011-08-02 19:51, Jonathan M Davis wrote: > >> I tried to convert a string into a wchar, but that didn't compile > >> because of this template constraint: > >> > >> https://github.com/D-Programming-Language/phobos/blob/master/std/conv. > >> d#L17 70 > >> > >> Is there a way to convert a string into a wchar? > > > > Does that even make sense? What do you want it to do, convert the first > > code point to a wchar and throw if there's more than one character in > > the string? That's like asking whether you can covert between a > > container of ints and an int. I would never expect std.conv.to to > > support that. Not to mention, you shouldn't normally be using char or > > wchar by themselves, because they might not be valid code points. > > Normally, only dchar should be used when representing an individual > > character. If you want this, I'd suggest that you simply do something > > like > > > > cast(wchar)str.front > > > > What you're asking for is inherently unsafe as far as unicode goes. > > > > - Jonathan M Davis > > I'm working on a serialization library and I intend to support as many > types as possible. So if someone serializes a single wchar I need to be > able to deserialize it. Since the serialized data is represented by a > string, in this case, I need to convert a string containing a single > character to a wchar when deserializing. > > Yes, convert the first code point to a wchar and then throw if there's > more the one character in the string.
Well, while it's understandable that you have to cover pretty every possible case of converting to and from a string with what you're doing, I don't think that it's at all reasonable to have std.conv.to convert a string to any character type, let alone one other than dchar. It's almost always a horrible idea and should _not_ be encouraged. So, I'd advise you to just find a way to deal with it appropriately in your own code. I think that it would be a very bad idea for std.conv.to or anything else in Phobos to support such a conversion. - Jonathan M Davis
