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digitalmars.D.learn - Operator Overloading with class template

reply "Eyyub" <eyyub.pangearaion gmail.com> writes:
Hello,

How can I rewrite the exemple 2 (http://pastebin.com/q50903Zh) in 
D lang. ?
This source code doesn't work...why ?
http://paste.pocoo.org/show/wy1kDIpqTi2ApRuOxRRb/

Thx. :)
Apr 08 2012
next sibling parent reply "Francois Chabot" <francois.chabot.dev gmail.com> writes:
On Sunday, 8 April 2012 at 23:14:33 UTC, Eyyub wrote:

 Hello,

 How can I rewrite the exemple 2 (http://pastebin.com/q50903Zh) 
 in D lang. ?
 This source code doesn't work...why ?
 http://paste.pocoo.org/show/wy1kDIpqTi2ApRuOxRRb/

 Thx. :)


As far as I know, there is nothing special about themplate 
classes with regards to operator overloading, so you can follow 
the examples in there: http://dlang.org/operatoroverloading.html

which in your example would yield:

Matrix opOpAssign(string op)( Matrix rhs )
{	
   for( size_t i =0 ; i < M ; ++i )
   {
     for( size_t j =0 ; j < N ; ++j )
     {
       mixin("array_[i*N+j]" ~ op ~ " rhs.array_[i*N+j] ;") ;
     }
   }
}

Bonus! all ...= operators implemented at once!
Apr 08 2012
parent reply "Francois Chabot" <francois.chabot.dev gmail.com> writes:
On Sunday, 8 April 2012 at 23:41:51 UTC, Francois Chabot wrote:

 On Sunday, 8 April 2012 at 23:14:33 UTC, Eyyub wrote:

 Hello,

 How can I rewrite the exemple 2 (http://pastebin.com/q50903Zh) 
 in D lang. ?
 This source code doesn't work...why ?
 http://paste.pocoo.org/show/wy1kDIpqTi2ApRuOxRRb/

 Thx. :)


 As far as I know, there is nothing special about themplate 
 classes with regards to operator overloading, so you can follow 
 the examples in there: http://dlang.org/operatoroverloading.html

 which in your example would yield:

 Matrix opOpAssign(string op)( Matrix rhs )
 {	
   for( size_t i =0 ; i < M ; ++i )
   {
     for( size_t j =0 ; j < N ; ++j )
     {
       mixin("array_[i*N+j]" ~ op ~ " rhs.array_[i*N+j] ;") ;
     }
   }
 }

 Bonus! all ...= operators implemented at once!


Nevermind, read your message too quickly... I thought it was 
about the matrix class...
Apr 08 2012
parent reply "Eyyub" <eyyub.pangearaion gmail.com> writes:
On Sunday, 8 April 2012 at 23:44:12 UTC, Francois Chabot wrote:

 On Sunday, 8 April 2012 at 23:41:51 UTC, Francois Chabot wrote:

 On Sunday, 8 April 2012 at 23:14:33 UTC, Eyyub wrote:

 Hello,

 How can I rewrite the exemple 2 
 (http://pastebin.com/q50903Zh) in D lang. ?
 This source code doesn't work...why ?
 http://paste.pocoo.org/show/wy1kDIpqTi2ApRuOxRRb/

 Thx. :)


 As far as I know, there is nothing special about themplate 
 classes with regards to operator overloading, so you can 
 follow the examples in there: 
 http://dlang.org/operatoroverloading.html

 which in your example would yield:

 Matrix opOpAssign(string op)( Matrix rhs )
 {	
  for( size_t i =0 ; i < M ; ++i )
  {
    for( size_t j =0 ; j < N ; ++j )
    {
      mixin("array_[i*N+j]" ~ op ~ " rhs.array_[i*N+j] ;") ;
    }
  }
 }

 Bonus! all ...= operators implemented at once!


 Nevermind, read your message too quickly... I thought it was 
 about the matrix class...


Np :D, you don't know how can I do for the example 2 ?
Apr 08 2012
parent reply Andrej Mitrovic <andrej.mitrovich gmail.com> writes:
On 4/9/12, Eyyub <eyyub.pangearaion gmail.com> wrote:

 Np :D, you don't know how can I do for the example 2 ?


Well for one thing, there are no global operators in D. Others might
help out with writing a proper opBinary that's defined in Value
itself.
Apr 08 2012
parent "Eyyub" <eyyub.pangearaion gmail.com> writes:
On Monday, 9 April 2012 at 00:04:50 UTC, Andrej Mitrovic wrote:

 On 4/9/12, Eyyub <eyyub.pangearaion gmail.com> wrote:

 Np :D, you don't know how can I do for the example 2 ?


 Well for one thing, there are no global operators in D. Others 
 might
 help out with writing a proper opBinary that's defined in Value
 itself.


Like this : http://paste.pocoo.org/show/VupvqFTLqZxvZajw71MA/ ? I 
have the same errors :s

Thanks
Apr 08 2012
prev sibling parent reply James Miller <james aatch.net> writes:
* Eyyub <eyyub.pangearaion gmail.com> [2012-04-09 01:14:32 +0200]:


 Hello,
 
 How can I rewrite the exemple 2 (http://pastebin.com/q50903Zh) in D
 lang. ?
 This source code doesn't work...why ?
 http://paste.pocoo.org/show/wy1kDIpqTi2ApRuOxRRb/
 
 Thx. :)
 


What you want is something like this:

    class Value(int M, int K, int S)
    {

        private
        {
            float _value;
        }

        public
        {
            this(float val)
            {
                _value = val;
            }

            auto opBinary(string op : "/", int MO, int KO, int SO)(Value(MO,
KO, SO) other) {
                return new Value!(M-MO, K-KO, S-SO)(_value/other.value);
            }

        }
    }

A Few notes:
1. This isn't tested, might not work, but thats where you should aim...
2. Operator overloading is implemented as a lowering (as far as I'm aware) the
   compiler emits a template instantiation of opBinary("/") for the type. That
   means that you can add on more template arguments.
3. Using `auto` means that the compiler works out the type, so you don't have
   to add extra template arguments to calculate the correct type.

Hope that helps.

--
James Miller
Apr 09 2012
parent "Eyyub" <eyyub.pangearaion gmail.com> writes:
On Monday, 9 April 2012 at 09:09:05 UTC, James Miller wrote:

 * Eyyub <eyyub.pangearaion gmail.com> [2012-04-09 01:14:32 
 +0200]:


 Hello,
 
 How can I rewrite the exemple 2 (http://pastebin.com/q50903Zh) 
 in D
 lang. ?
 This source code doesn't work...why ?
 http://paste.pocoo.org/show/wy1kDIpqTi2ApRuOxRRb/
 
 Thx. :)
 


 What you want is something like this:

     class Value(int M, int K, int S)
     {

         private
         {
             float _value;
         }

         public
         {
             this(float val)
             {
                 _value = val;
             }

             auto opBinary(string op : "/", int MO, int KO, int 
 SO)(Value(MO, KO, SO) other) {
                 return new Value!(M-MO, K-KO, 
 S-SO)(_value/other.value);
             }

         }
     }

 A Few notes:
 1. This isn't tested, might not work, but thats where you 
 should aim...
 2. Operator overloading is implemented as a lowering (as far as 
 I'm aware) the
    compiler emits a template instantiation of opBinary("/") for 
 the type. That
    means that you can add on more template arguments.
 3. Using `auto` means that the compiler works out the type, so 
 you don't have
    to add extra template arguments to calculate the correct 
 type.

 Hope that helps.

 --
 James Miller


Ho, yeah it works !!! :D :D

http://paste.pocoo.org/show/ye7VXQHfLxsVM38bKyS6/

Thanks a lot !
Apr 09 2012