Hello,
why ... cannot be used with structs?

struct Foo {
    this(int a) { }
}

void bar(Foo foo...) {

}

bar(42);

On 21/10/2016 1:48 AM, Satoshi wrote:
> Hello,
> why ... cannot be used with structs?
>
> struct Foo {
>     this(int a) { }
> }
>
> void bar(Foo foo...) {
>
> }
>
> bar(42);

Because an int is not a Foo.

On Thursday, 20 October 2016 at 12:52:42 UTC, rikki cattermole wrote:
> On 21/10/2016 1:48 AM, Satoshi wrote:
>> Hello,
>> why ... cannot be used with structs?
>>
>> struct Foo {
>>     this(int a) { }
>> }
>>
>> void bar(Foo foo...) {
>>
>> }
>>
>> bar(42);
>
> Because an int is not a Foo.


Oh, really? I didn't notice that... (sarcasm)

If I change struct Foo to class Foo it works.

On Thursday, 20 October 2016 at 12:48:34 UTC, Satoshi wrote:
> Hello,
> why ... cannot be used with structs?
>
> struct Foo {
>     this(int a) { }
> }
>
> void bar(Foo foo...) {
>
> }
>
> bar(42);

Being explicit about these things makes complex code more clear.

On Thursday, 20 October 2016 at 16:04:00 UTC, Nordlöw wrote:
> On Thursday, 20 October 2016 at 12:48:34 UTC, Satoshi wrote:
>> Hello,
>> why ... cannot be used with structs?
>>
>> struct Foo {
>>     this(int a) { }
>> }
>>
>> void bar(Foo foo...) {
>>
>> }
>>
>> bar(42);
>
> Being explicit about these things makes complex code more clear.

With class it works fine.
https://dlang.org/spec/function.html#typesafe_variadic_functions

I have struct Point(x, y) and I want to let the people call some methods with Point or just pass x and y argument. I can make Point as a class but it's not efficient.

I think this
void moveMouseTo(float x, float y);
is same clear as
void moveMouseTo(Point point);

On Thursday, 20 October 2016 at 14:29:53 UTC, Satoshi wrote:
> Oh, really? I didn't notice that... (sarcasm)
>
> If I change struct Foo to class Foo it works.

It's because for some weird reason, this type of varargs allows implicit construction of an object. I don't know why, it's just a feature that was added a long time ago and never removed. However as you can see, it doesn't work for structs and IMO you should never use it.