According to the std.utf documentation,
decode will only work with strings and random access ranges of
code units with length and slicing, whereas decodeFront will
work with any input range of code units.
However, I can't seem to get such a usage to compile: the
following code
import std.range;
import std.utf;
void somefn(InputRange!(ubyte) r) {
r.decodeFront!(No.useReplacementDchar, dchar)();
}
gives a compilation error:
onlineapp.d(5): Error: template std.utf.decodeFront cannot deduce
function from argument types !(cast(Flag)false,
dchar)(InputRange!ubyte), candidates are:
/dlang/dmd/linux/bin64/../../src/phobos/std/utf.d(1176):
std.utf.decodeFront(Flag useReplacementDchar =
No.useReplacementDchar, S)(ref S str, out size_t numCodeUnits) if
(!isSomeString!S && isInputRange!S && isSomeChar!(ElementType!S))
/dlang/dmd/linux/bin64/../../src/phobos/std/utf.d(1214):
std.utf.decodeFront(Flag useReplacementDchar =
No.useReplacementDchar, S)(ref S str, out size_t numCodeUnits) if
(isSomeString!S)
/dlang/dmd/linux/bin64/../../src/phobos/std/utf.d(1243):
std.utf.decodeFront(Flag useReplacementDchar =
No.useReplacementDchar, S)(ref S str) if (isInputRange!S &&
isSomeChar!(ElementType!S))
I'm not sure what's wrong here. Also, the information in the
error message seems to indicate that decodeFront isn't expecting
to work on a generic InputRange interface, but rather a subset
which comes from an actual string. Have I read that wrong? I get
the same error with leaving out the useReplacementDchar flag,
i.e. `r.decodeFront!(dchar)()`
