I'm getting conflicting templates in this struct and I'm not sure how. I specifically excluded the second definition of opAdd from using type T in place of O but the compiler still tells me I'm getting template conflicts.

Compiler error using Mass!(double,string):

Error: template mass.Mass!(double,string).Mass.opAdd(O) if ((typeof(O)) != (typeof(T))) conflicts with function mass.Mass!(double,string).Mass.opAdd at src\mass.d(38)


I have a struct:

struct Mass(T, S) {
	...
	
	Mass!(T,S) opAdd(Mass!(T,S) other) {
		return op!"+"(other);
	}
	
	Mass!(O,S) opAdd(O)(Mass!(O,S) other) if (typeof(O) != typeof(T)) {
		return op!"+"(other);
	}
...
}

And I'm trying to do something like:

	Mass!(double,string) first = ...
	Mass!(double,string) second = ...
	
	auto result = first + second;

I'm trying to add a Mass!(double,string) + Mass!(double,string), which should mean the second template gets ignored since T=double and O=double.

What am I missing?

John:

> 	Mass!(T,S) opAdd(Mass!(T,S) other) {

If you are using D2 then don't use opAdd, use opBinary:

http://dlang.org/operatoroverloading.html#Binary

Bye,
bearophile

On Tuesday, 2 July 2013 at 00:01:48 UTC, bearophile wrote:
> John:
>
>> 	Mass!(T,S) opAdd(Mass!(T,S) other) {
>
> If you are using D2 then don't use opAdd, use opBinary:
>
> http://dlang.org/operatoroverloading.html#Binary
>
> Bye,
> bearophile

Thanks, I switched over to using the new function and after fiddling with the functions I came up with a pair that seem to work.

Mass!(T,S) opBinary(alias operator)(Mass!(T,S) other) {
Mass!(T,S) opBinary(alias operator, O)(Mass!(O,S) other) if (!is(O == T)) {

On Monday, 1 July 2013 at 23:36:27 UTC, John wrote:
> struct Mass(T, S) {
> 	...
> 	
> 	Mass!(T,S) opAdd(Mass!(T,S) other) {

You can't overload non-templates with templates, yet. It's supposed to work, but not implemented. The workaround is simple enough:

Mass!(T,S) opAdd()(Mass!(T,S) other) { // note the () after opAdd

> 		return op!"+"(other);
> 	}
> 	
> 	Mass!(O,S) opAdd(O)(Mass!(O,S) other) if (typeof(O) != typeof(T)) {

That constraint should be: if (!is(O == T))

> 		return op!"+"(other);
> 	}
> ...
> }

John:

> Mass!(T,S) opBinary(alias operator)(Mass!(T,S) other) {
> Mass!(T,S) opBinary(alias operator, O)(Mass!(O,S) other) if (!is(O == T)) {

Isn't operator better as string?

----------------------

anonymous:

> You can't overload non-templates with templates,

I think it was recently fixed in Git.

Bye,
bearophile

On Tuesday, 2 July 2013 at 01:24:18 UTC, bearophile wrote:
> anonymous:
>
>> You can't overload non-templates with templates,
>
> I think it was recently fixed in Git.

It's still buggy then, since adding the empty parentheses makes the error go away.

On Tuesday, 2 July 2013 at 01:39:22 UTC, anonymous wrote:
> On Tuesday, 2 July 2013 at 01:24:18 UTC, bearophile wrote:
>> anonymous:
>>
>>> You can't overload non-templates with templates,
>>
>> I think it was recently fixed in Git.
>
> It's still buggy then, since adding the empty parentheses makes the error go away.

... or maybe my checkout wasn't up to date ;)

> John:
>
>> 	Mass!(T,S) opAdd(Mass!(T,S) other) {
>
> If you are using D2 then don't use opAdd, use opBinary:
>
> http://dlang.org/operatoroverloading.html#Binary

Time ago I added an enhancement request for a warning (that later is meant to become a deprecation) that helps avoid your problem:

http://d.puremagic.com/issues/show_bug.cgi?id=10320

Bye,
bearophile