Re: casting with preserving attributes
Jack Applegame:
Finally http://dpaste.1azy.net/fc503331
I suggest to use indents composed by 4 spaces.
Generally in D we use template constraints, instead of static ifs
with a nice error message...
In such complex situations I also suggest to add braces.
Something like this:
auto castElementType(T = byte, F)(ref F from)
if (isArray!F) {
alias E = typeof(from[0]);
static if(is(E == const)) {
return cast(const(Unqual!T)[])from;
} else static if(is(E == immutable)) {
return cast(immutable(Unqual!T)[])from;
} else static if(is(E == shared)) {
return cast(shared(Unqual!T)[])from;
} else {
return cast(Unqual!T[])from;
}
}
Bye,
bearophile
Re: casting with preserving attributes
On Wednesday, 22 May 2013 at 13:01:26 UTC, bearophile wrote: I think that's essentially the right solution. I suggest to generalize it a bit, removing the byte from its insides, and making it a template argument. I think "shared" is missing. Yes. Finally http://dpaste.1azy.net/fc503331
Re: casting with preserving attributes
I found awkward solution:
template ByteType(alias t) {
alias typeof(t) T;
static if(is(ElementType!T == const)) alias const(byte)[]
ByteType;
else static if(is(ElementType!T == immutable)) alias
immutable(byte)[] ByteType;
else alias byte[] ByteType;
}
Re: casting with preserving attributes
Jack Applegame:
I found awkward solution:
template ByteType(alias t) {
alias typeof(t) T;
static if(is(ElementType!T == const)) alias const(byte)[]
ByteType;
else static if(is(ElementType!T == immutable)) alias
immutable(byte)[] ByteType;
else alias byte[] ByteType;
}
I think that's essentially the right solution. I suggest to
generalize it a bit, removing the byte from its insides, and
making it a template argument. I think "shared" is missing.
Bye,
bearophile
casting with preserving attributes
Hello.
I need a template for casting arrays to another type without
changing const and immutable attributes:
template ByteType(T) {
// some magic
}
const(int)[] ca;
immutable(short)[] is;
long[] ml;
static assert(is(ByteType!ca == const(byte)[]));
static assert(is(ByteType!is == immutable(byte)[]));
static assert(is(ByteType!ml == byte[]));
What kind of template magic I should use?
