Re: Type deduction on templated constructor.
On Wed, Jul 30, 2014 at 11:46 AM, Philippe Sigaud wrote: >> I expected such an answer and I do understand the decisions behind it. Yet, >> you gave me a really GOOD news! Having to write cast(ubyte) 1 was way too >> much verbose for my liking, while the new ubyte(1) is reasonable enough. > > Why not use `1u`? Ow! Ignore that. 1u is an uint, not an ubyte.
Re: Type deduction on templated constructor.
> I expected such an answer and I do understand the decisions behind it. Yet, > you gave me a really GOOD news! Having to write cast(ubyte) 1 was way too > much verbose for my liking, while the new ubyte(1) is reasonable enough. Why not use `1u`?
Re: Type deduction on templated constructor.
On Thursday, 24 July 2014 at 09:38:14 UTC, bearophile wrote: francesco cattoglio: should this code compile? I understand that the literal "1" is "int" therefore it can screw type deduction, but I wonder if the compiler should be smart enough to deduce it correctly. To keep both the compiler and programmers sane, D templates don't perform implicit type conversions. This sometimes is not handy, but on the whole saves from a large number of troubles. So you can write (D V.2.066): Vector!ubyte(ubyte(1), ubyte(1), ubyte(1)); Or you can create a little helper function that makes that code more DRY. Bye, bearophile I expected such an answer and I do understand the decisions behind it. Yet, you gave me a really GOOD news! Having to write cast(ubyte) 1 was way too much verbose for my liking, while the new ubyte(1) is reasonable enough.
Re: Type deduction on templated constructor.
francesco cattoglio: should this code compile? I understand that the literal "1" is "int" therefore it can screw type deduction, but I wonder if the compiler should be smart enough to deduce it correctly. To keep both the compiler and programmers sane, D templates don't perform implicit type conversions. This sometimes is not handy, but on the whole saves from a large number of troubles. So you can write (D V.2.066): Vector!ubyte(ubyte(1), ubyte(1), ubyte(1)); Or you can create a little helper function that makes that code more DRY. Bye, bearophile
Type deduction on templated constructor.
So, I have this code (also on http://dpaste.dzfl.pl/3f767b17e83c)
This Vector(T) struct is taken from gfm.math.vector.
struct Vector(T) {
T x, y, z;
this(X : T, Y : T, Z : T)(X x_, Y y_, Z z_)
{
x = x_; y = y_; z = z_;
}
}
void main()
{
Vector!ubyte test = Vector!ubyte(1, 1, 1);
}
It fails to compile because "template
f508.Vector!ubyte.Vector.__ctor cannot deduce function from
argument types !()(int, int, int)".
Note that if one just defines a constructor as this(T x_, T y_, T
z_) everything works.
My question is: should this code compile? I understand that the
literal "1" is "int" therefore it can screw type deduction, but I
wonder if the compiler should be smart enough to deduce it
correctly.
