• james.p.leblanc (24/24) Aug 23 2021 Greetings,
• =?UTF-8?Q?Ali_=c3=87ehreli?= (19/19) Aug 23 2021 On 8/23/21 10:25 PM, james.p.leblanc wrote:
• james.p.leblanc (12/31) Aug 23 2021 Ali,

james.p.leblanc <james.p.leblanc gmail.com> writes:

Greetings,

With a struct, there are many overload possibilities available.

However, I haven't been able to find how to overload assignment
of **selected fields** of a struct.

For example, suppose:

     struct Foo{
       int a;
       int b;
       ...
     }

     void main(){
         auto x = Foo( 1, 2);  // so x now instantiates

         x.a = 100;             // suppose I wish to enforce that 
a<5??
     ...
     }


(I understand this is basically a field "setter" idea that is most
often associated with classes.  So, another way to state the 
quesion
might be:  "How can a field setter be done on a **already 
instantiated**
struct?)

Best Regards,
James

=?UTF-8?Q?Ali_=c3=87ehreli?= <acehreli yahoo.com> writes:

On 8/23/21 10:25 PM, james.p.leblanc wrote:

So, you need a "property". Easy... :)

1) Rename the member e.g. as a_.

2) Write setter and getter functions named 'a'.

struct Foo{
   int a_;

   int a() const {
     return a_;
   }

   void a(int value) {
     a_ = value;
   }
}

void main(){
   auto x = Foo(1);
   x.a = 100;
   assert(x.a == 100);
}

Ali

james.p.leblanc <james.p.leblanc gmail.com> writes:

On Tuesday, 24 August 2021 at 05:34:08 UTC, Ali Çehreli wrote:
 On 8/23/21 10:25 PM, james.p.leblanc wrote:

 So, you need a "property". Easy... :)

 1) Rename the member e.g. as a_.

 2) Write setter and getter functions named 'a'.

 struct Foo{
   int a_;

   int a() const {
     return a_;
   }

   void a(int value) {
     a_ = value;
   }
 }

 void main(){
   auto x = Foo(1);
   x.a = 100;
   assert(x.a == 100);
 }

 Ali

Ali,

Thank you ... yes!  This is exactly what I needed, I have done 
something
similar as you have shown for the "getter", but had a 
"brain-lock-up"
when thinking about the setter.

A bit embarassing for my, I admit.  But, on the positive side ... 
the
solution is now burned into my brain.

Thanks again and Kind Regards,
James