Re: casting with preserving attributes

2013-05-22 Thread bearophile 

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

2013-05-22 Thread Jack Applegame 

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

2013-05-22 Thread 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;
}

Re: casting with preserving attributes

2013-05-22 Thread bearophile 

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