Yigal Chripun:
> .Net generics for example work by creating an instantiation for each
> value type (same as c++ templates) and one instantiation for all
> reference types since at the binary level all reference types are simply
> addresses. C++ can't do this since it has no separation between
> "structs" and "classes".
> there is no casting involved since the full type info is stored.
> so a Foo<Bar> will be typed as Foo<Bar> at the binary level as well and
> you can use APIs to query this at runtime.
In D structs and classes are distinct enough, but they currently produce
duplicated templated code, this may be fixed:
void foo(T)(T o) {
printf("foo: %d\n", o.y);
}
class A { int x = 1; }
class B : A { int y = 2; }
class C : A { int y = 3; }
void main() {
B b = new B();
C c = new C();
foo(b);
foo(c);
}
/*
DMD1:
_D4temp17__T3fooTC4temp1BZ3fooFC4temp1BZv comdat
push EAX
mov ECX,offset FLAT:_D4temp1C6__vtblZ[018h]
push dword ptr 0Ch[EAX]
push ECX
call near ptr _printf
add ESP,8
pop EAX
ret
_D4temp17__T3fooTC4temp1CZ3fooFC4temp1CZv comdat
push EAX
mov ECX,offset FLAT:_D4temp1C6__vtblZ[018h]
push dword ptr 0Ch[EAX]
push ECX
call near ptr _printf
add ESP,8
pop EAX
ret
LDC:
_D13testtemplates27__T3fooTC13testtemplates1BZ3fooFC13testtemplates1BZv:
subl $12, %esp
movl 12(%eax), %eax
movl %eax, 4(%esp)
movl $.str3, (%esp)
call printf
addl $12, %esp
ret
_D13testtemplates27__T3fooTC13testtemplates1CZ3fooFC13testtemplates1CZv:
subl $12, %esp
movl 12(%eax), %eax
movl %eax, 4(%esp)
movl $.str3, (%esp)
call printf
addl $12, %esp
ret
*/
Bye,
bearophile
