std.utf.decode("dlang", 1)

[Ali Çehreli via Digitalmars-d-learn]

On 09/17/2014 11:23 PM, Algo wrote:
> On Thursday, 18 September 2014 at 06:09:54 UTC, Algo wrote:
>> void main()
>> {
>>       import std.utf;
>>       decode("dlang", 1);
>> }
>>
>> Error: template std.utf.decode cannot deduce function from
>> argument types !()(string, int), candidates are:
>> D:\msc\D\dmd2\windows\bin\..\..\src\phobos\std\utf.d(924):
>> std.utf.decode(S)(auto ref S str, ref size_t index) if
>> (!isSomeString!S && isRandomAccessRange!S && hasSlicing!S &&
>> hasLength!S && isSomeChar!(ElementType!S))
>> D:\msc\D\dmd2\windows\bin\..\..\src\phobos\std\utf.d(942):
>> std.utf.decode(S)(auto ref S str, ref size_t index) if
>> (isSomeString!S)
>>
>> why doesn't "decode(S)(auto ref S str, ref size_t index) if
>> (isSomeString!S)" correspond?
>
> rvalues cannot be ref it seems

Yes. Interestingly, in D rvalues cannot be bound even to const ref.

void main()
{
     import std.stdio;
     import std.utf;

     size_t index = 1;
     dchar decoded = decode("dlang", index);

     writefln("decoded '%s', next character is at index %s.",
              decoded, index);
}

The output:

decoded 'l', next character is at index 2.

Ali