• Jack (41/41) Jan 25 2021 I'd like to make this work s += 10 where s is a struct. How can I
• Adam D. Ruppe (7/8) Jan 25 2021 try
• Jack (2/10) Jan 25 2021 it did work, thanks. That naming is confusing
• Q. Schroll (10/11) Jan 25 2021 op: it is an operator method
• Paul Backus (4/6) Jan 25 2021 +=, -=, *=, and other compound assignment operators can be
• Jack (2/8) Jan 25 2021 thanks
• bachmeier (5/7) Jan 26 2021 You have your answer, but someone else might come upon this in

Jack <jckj33 gmail.com> writes:

I'd like to make this work s += 10 where s is a struct. How can I 
do that?
this isn't working:

     auto ref opAssign(string op, T)(T value)
     if(op == "+")
     {
         m += value;
         return this;
     }

the compiler didn't consider that overload and return:

d.d(34): Error: s is not a scalar, it is a S

full code:

     auto s = S(10);
     writeln(--s);
     s += 5;
     writeln(s);

struct S
{
     int m;

     int opUnary(string op)()
     {
         static if(op == "--")
             return --m;
         else static if(op == "++")
             return ++m;
         else
             static assert(0, "unsupported operator");
     }

     void opBinary(string op, R)(const R rhs)
     if(op == "+")
     {
         m += rhs;
         return this;
     }

     auto ref opAssign(string op, T)(T value)
     if(op == "+")
     {
         m += value;
         return this;
     }
}

Adam D. Ruppe <destructionator gmail.com> writes:

On Monday, 25 January 2021 at 17:09:22 UTC, Jack wrote:
     auto ref opAssign(string op, T)(T value)

try

opOpAssign instead

opAssign is for =

opOpAssign is for +=, -=, etc.

It might be some variation but I think it works if you just 
rename it.

Jack <jckj33 gmail.com> writes:

On Monday, 25 January 2021 at 17:11:41 UTC, Adam D. Ruppe wrote:
 On Monday, 25 January 2021 at 17:09:22 UTC, Jack wrote:
     auto ref opAssign(string op, T)(T value)

 try

 opOpAssign instead

 opAssign is for =

 opOpAssign is for +=, -=, etc.

 It might be some variation but I think it works if you just 
 rename it.

it did work, thanks. That naming is confusing

Q. Schroll <qs.il.paperinik gmail.com> writes:

On Monday, 25 January 2021 at 21:53:15 UTC, Jack wrote:
 That naming is confusing

op: it is an operator method
Op: it takes an operator as a parameter
Assign: kinda obvious.

As an example, there are opIndex, opIndexAssign and 
opIndexOpAssign.
opIndex overloads obj[i].
opIndexAssign overloads obj[i] = rhs, and
opIndexOpAssign overloads opj[i] += rhs.

Maybe, in the greater scheme, the naming makes more sense to you.

Paul Backus <snarwin gmail.com> writes:

On Monday, 25 January 2021 at 17:09:22 UTC, Jack wrote:
 I'd like to make this work s += 10 where s is a struct. How can 
 I do that?

+=, -=, *=, and other compound assignment operators can be 
overloaded by defining `opOpAssign`:

https://dlang.org/spec/operatoroverloading.html#op-assign

Jack <jckj33 gmail.com> writes:

On Monday, 25 January 2021 at 17:12:47 UTC, Paul Backus wrote:
 On Monday, 25 January 2021 at 17:09:22 UTC, Jack wrote:
 I'd like to make this work s += 10 where s is a struct. How 
 can I do that?

 +=, -=, *=, and other compound assignment operators can be 
 overloaded by defining `opOpAssign`:

 https://dlang.org/spec/operatoroverloading.html#op-assign

thanks

bachmeier <no spam.net> writes:

On Monday, 25 January 2021 at 17:09:22 UTC, Jack wrote:
 I'd like to make this work s += 10 where s is a struct. How can 
 I do that?

You have your answer, but someone else might come upon this in 
the future, so here's a link to the clearest explanation of 
operator overloading for someone new to the language:

http://ddili.org/ders/d.en/operator_overloading.html