• dominic jones (14/14) Apr 20 2012 Hello,
• bearophile (9/14) Apr 20 2012 You can't overload the operator of a primitive, but binary
• Mafi (4/15) Apr 20 2012 Shouldn't a consequence of UFCS be that you can overload binary
• H. S. Teoh (8/27) Apr 20 2012 UFCS only kicks in if no matching method is found for the given type. So

"dominic jones" <dominic.jones gmx.co.uk> writes:

Hello,

I want to overload a primitive type operator so that I can do 
something like

double a;
myStruct b;
writeln(a + b);

but have no idea how to do it. Something similar(?) is already 
implemented in the language, i.e.

double x;
double[] y;
writeln(x + y);

but after searching the dmd2/src, what I found didn't offer any 
help.

-Dominic Jones

"bearophile" <bearophileHUGS lycos.com> writes:

Dominic Jones:

 I want to overload a primitive type operator so that I can do 
 something like

 double a;
 myStruct b;
 writeln(a + b);

You can't overload the operator of a primitive, but binary 
operators come in left and right versions:
http://dlang.org/operatoroverloading.html#Binary

a.opBinary!("op")(b)
b.opBinaryRight!("op")(a)

so adding an inverse "+" operator inside myStruct is possible.

Bye,
bearophile

Mafi <mafi example.org> writes:

Am 20.04.2012 18:41, schrieb bearophile:
 Dominic Jones:

 I want to overload a primitive type operator so that I can do
 something like

 double a;
 myStruct b;
 writeln(a + b);

 You can't overload the operator of a primitive, but binary operators
 come in left and right versions:

...
 Bye,
 bearophile

Shouldn't a consequence of UFCS be that you can overload binary 
operators for primitives, as should global overloads (like in C++).

"H. S. Teoh" <hsteoh quickfur.ath.cx> writes:

On Fri, Apr 20, 2012 at 07:12:41PM +0200, Mafi wrote:
 Am 20.04.2012 18:41, schrieb bearophile:
Dominic Jones:

I want to overload a primitive type operator so that I can do
something like

double a;
myStruct b;
writeln(a + b);

You can't overload the operator of a primitive, but binary operators
come in left and right versions:

 ...
Bye,
bearophile

 
 Shouldn't a consequence of UFCS be that you can overload binary
 operators for primitives, as should global overloads (like in C++).

UFCS only kicks in if no matching method is found for the given type. So
UFCS can be used to provide "default" implementations for when an
operator is not defined for a given type, but the operator defined by
the type takes precedence over UFCS.


T

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