Namespace:
Your gig:
https://github.com/D-Programming-Language/dmd/pull/2952#discussion_r8288045
This is part of the thread there:
Furhtermore, what if we indeed want to pass a dynamic array ?<<
Kenji> Use cast. In real world, if overloaded function takes both
int[] and int[3], normally int[3] version would provide
specialized implementation for 3 length arrays (eg. unroll the
loop to operate each elements of the given array). Therefore
force to invoke int[] version with array literal is not usual
situation. Cast will fit in such case.<
If I have a function foo that takes a slice as input, and I want
to pass it two arrays, the first time allocated on the heap and
the second on the stack, I have to use an auxiliary variable:
void foo(int[]) {}
void main() {
foo([1, 2, 3]);
int[3] tmp = [4, 5, 6];
foo(tmp);
}
DMD generates:
__Dmain comdat
L0: push EBX
mov EAX,offset FLAT:_D11TypeInfo_Ai6__initZ
push 3
push EAX
call near ptr __d_arrayliteralTX
mov EBX,EAX
mov dword ptr [EAX],1
xor EAX,EAX
mov dword ptr 4[EBX],2
mov dword ptr 8[EBX],3
add ESP,8
pop EBX
ret
With the []s syntax it should become:
void foo(int[]) {}
void main() {
foo([1, 2, 3]);
foo([4, 5, 6]s);
}
But I don't know how much common is such need.
In the Rust language when you write an array literal you always
prefix it with a symbol, to tell the compiler where you want to
allocate it. So I think it's not so useless :-)
Bye,
bearophile
