www.digitalmars.com         C & C++   DMDScript  

digitalmars.D.learn - implicit casting from primitive type

reply Mariusz =?UTF-8?B?R2xpd2nFhHNraQ==?= <alienballance gmail.com> writes:
Hello,
this will be easy question. I defined attributes, that are taking my custom 
structures as attributes. Then, I'd like to add implicit conversion to this 
structures from primitive types, such as:
<code>
some.attribute = [1, 2, 3];   // i'd like to do that
some.attribute = MyStruct(1, 2, 3); // now it's like that
</code>
opCast can be used only to casting FROM my type, but not TO...
Was that in a book?

Thanks,
Mariusz Gliwiński
Aug 29 2011
parent reply Ali =?iso-8859-1?q?=C7ehreli?= <acehreli yahoo.com> writes:
On Mon, 29 Aug 2011 21:33:13 +0200, Mariusz Gliwiński wrote:


 Hello,
 this will be easy question. I defined attributes, that are taking my
 custom structures as attributes. Then, I'd like to add implicit
 conversion to this structures from primitive types, such as: <code>
 some.attribute = [1, 2, 3];   // i'd like to do that some.attribute =
 MyStruct(1, 2, 3); // now it's like that </code>
 opCast can be used only to casting FROM my type, but not TO... Was that
 in a book?
 
 Thanks,
 Mariusz Gliwiński


To solve it for this specific case, you can overload attribute() to take 
int[]:

import std.exception;

struct MyStruct
{
    int i;
    int j;
    int k;
}

struct CustomStruct
{
    MyStruct ms;

     property void attribute(int[] args)
    {
        enforce(args.length == 3);
        ms = MyStruct(args[0], args[1], args[2]);
    }
}

void main()
{
    auto some = CustomStruct();
    some.attribute = [ 1, 2, 3 ];
}

Ali
Aug 29 2011
parent Mariusz =?UTF-8?B?R2xpd2nFhHNraQ==?= <alienballance gmail.com> writes:
Ali Çehreli wrote:

 To solve it for this specific case, you can overload attribute() to take
 int[]:


I know, but i don't really want to. Too many overrides or templates, but 
i'll consider it if wont find any better solution.

Thanks,
Mariusz Gliwiński
Aug 29 2011