digitalmars.D.learn

digitalmars.D.learn - Delegator

bioinfornatics (18/18) Mar 03 2012 hi,

bioinfornatics (4/27) Mar 03 2012 I miss the question ^^

Jacob Carlborg (10/37) Mar 03 2012 I would say "yes", but not with the same pretty syntax. Something like t...

bioinfornatics (6/47) Mar 03 2012 is:
bioinfornatics (6/47) Mar 03 2012 is:
bioinfornatics (67/108) Mar 03 2012 is:

Adam D. Ruppe (14/15) Mar 03 2012 alias this does that, although it does for all unknown

bioinfornatics (2/25) Mar 03 2012 But when you have already a ctor ( class ) can you alias this ?

bioinfornatics <bioinfornatics fedoraproject.org> writes:

hi,
In ruby we can delegate some method. by example:
---- Ruby ----
class MineArray
  include Forwardable
  def_delegators:  array, :[], :[]=3D, :each_with_index, :length

  def initialize( array )
     array =3D array
  end
end
-------------

this code delegate opIndexAssign opIndex, length ... attribute to his
member.

This save time, bug and line. You do not to have to write a code as:
void opIndexAssign( size_t index, T item){
	array[index] =3D item;
}

thanks

Mar 03 2012

bioinfornatics <bioinfornatics fedoraproject.org> writes:

Le samedi 03 mars 2012 =C3=A0 17:42 +0100, bioinfornatics a =C3=A9crit :
 hi,
 In ruby we can delegate some method. by example:
 ---- Ruby ----
 class MineArray
   include Forwardable
   def_delegators:  array, :[], :[]=3D, :each_with_index, :length
=20
   def initialize( array )
      array =3D array
   end
 end
 -------------
=20
 this code delegate opIndexAssign opIndex, length ... attribute to his
 member.
=20
 This save time, bug and line. You do not to have to write a code as:
 void opIndexAssign( size_t index, T item){
 	array[index] =3D item;
 }
=20
 thanks
=20

I miss the question ^^

can w do same in D ?

thanks

Mar 03 2012

Jacob Carlborg <doob me.com> writes:

On 2012-03-03 17:50, bioinfornatics wrote:
 Le samedi 03 mars 2012 à 17:42 +0100, bioinfornatics a écrit :
 hi,
 In ruby we can delegate some method. by example:
 ---- Ruby ----
 class MineArray
    include Forwardable
    def_delegators:  array, :[], :[]=, :each_with_index, :length

    def initialize( array )
       array = array
    end
 end
 -------------

 this code delegate opIndexAssign opIndex, length ... attribute to his
 member.

 This save time, bug and line. You do not to have to write a code as:
 void opIndexAssign( size_t index, T item){
 	array[index] = item;
 }

 thanks

 I miss the question ^^

 can w do same in D ?

 thanks

I would say "yes", but not with the same pretty syntax. Something like this:

class MineArray
{
     mixin delegates!(array, "opIndexAssign", "opIndex");
}

Just implement "delegates" to generate the given functions and forward 
them to "array".

-- 
/Jacob Carlborg

Mar 03 2012

bioinfornatics <bioinfornatics fedoraproject.org> writes:

Le samedi 03 mars 2012 =C3=A0 19:18 +0100, Jacob Carlborg a =C3=A9crit :
 On 2012-03-03 17:50, bioinfornatics wrote:
 Le samedi 03 mars 2012 =C3=A0 17:42 +0100, bioinfornatics a =C3=A9crit =


:
 hi,
 In ruby we can delegate some method. by example:
 ---- Ruby ----
 class MineArray
    include Forwardable
    def_delegators:  array, :[], :[]=3D, :each_with_index, :length

    def initialize( array )
       array =3D array
    end
 end
 -------------

 this code delegate opIndexAssign opIndex, length ... attribute to his
 member.

 This save time, bug and line. You do not to have to write a code as:
 void opIndexAssign( size_t index, T item){
 	array[index] =3D item;
 }

 thanks

 I miss the question ^^

 can w do same in D ?

 thanks

=20
 I would say "yes", but not with the same pretty syntax. Something like th=

is:
=20
 class MineArray
 {
      mixin delegates!(array, "opIndexAssign", "opIndex");
 }
=20
 Just implement "delegates" to generate the given functions and forward=

=20
 them to "array".
=20

they are a way to create a decorator as  delgator for able to this
pretty ?

Mar 03 2012

bioinfornatics <bioinfornatics fedoraproject.org> writes:

Le samedi 03 mars 2012 =C3=A0 19:18 +0100, Jacob Carlborg a =C3=A9crit :
 On 2012-03-03 17:50, bioinfornatics wrote:
 Le samedi 03 mars 2012 =C3=A0 17:42 +0100, bioinfornatics a =C3=A9crit =


:
 hi,
 In ruby we can delegate some method. by example:
 ---- Ruby ----
 class MineArray
    include Forwardable
    def_delegators:  array, :[], :[]=3D, :each_with_index, :length

    def initialize( array )
       array =3D array
    end
 end
 -------------

 this code delegate opIndexAssign opIndex, length ... attribute to his
 member.

 This save time, bug and line. You do not to have to write a code as:
 void opIndexAssign( size_t index, T item){
 	array[index] =3D item;
 }

 thanks

 I miss the question ^^

 can w do same in D ?

 thanks

=20
 I would say "yes", but not with the same pretty syntax. Something like th=

is:
=20
 class MineArray
 {
      mixin delegates!(array, "opIndexAssign", "opIndex");
 }
=20
 Just implement "delegates" to generate the given functions and forward=

=20
 them to "array".
=20


I found this way verys interestiong. Could you put plsease a shorter
implementation of delegates?

Mar 03 2012

bioinfornatics <bioinfornatics fedoraproject.org> writes:

Le samedi 03 mars 2012 =C3=A0 19:18 +0100, Jacob Carlborg a =C3=A9crit :
 On 2012-03-03 17:50, bioinfornatics wrote:
 Le samedi 03 mars 2012 =C3=A0 17:42 +0100, bioinfornatics a =C3=A9crit =


:
 hi,
 In ruby we can delegate some method. by example:
 ---- Ruby ----
 class MineArray
    include Forwardable
    def_delegators:  array, :[], :[]=3D, :each_with_index, :length

    def initialize( array )
       array =3D array
    end
 end
 -------------

 this code delegate opIndexAssign opIndex, length ... attribute to his
 member.

 This save time, bug and line. You do not to have to write a code as:
 void opIndexAssign( size_t index, T item){
 	array[index] =3D item;
 }

 thanks

 I miss the question ^^

 can w do same in D ?

 thanks

=20
 I would say "yes", but not with the same pretty syntax. Something like th=

is:
=20
 class MineArray
 {
      mixin delegates!(array, "opIndexAssign", "opIndex");
 }
=20
 Just implement "delegates" to generate the given functions and forward=

=20
 them to "array".
=20


I have try to do a mixin template but i fail
------------------ D Code --------------------
import std.string;
import std.stdio;
import std.range;

mixin template arrayDelegator( alias instance, methods... ){
    string result;
   static if( methods.length > 0 ){
        static if( "opIndexAssign" ){
            result ~=3D"
    void opIndexAssign( size_t index, " ~
ElementEncodingType!(typeof(instance)) ~ " item ){=20
        array[index] =3D item;
    }
                    ";
        }
        static else if( "opIndex" ){
            result ~=3D"
    " ~ ElementEncodingType!(typeof(instance)) ~ " opIndex( size_t index
){
        return instance[index];
    }
                    ";
        }
        static else if( "length" ){
            result ~=3D"
     property size_t length(){
        return instance.length;
    }
                    ";
        }
        static else
            throw new Exception( "Unknown methods: "~ method );
        static if( methods.length > 2 )
            arrayDelegator!( instance, methods[1 .. $ ] );
    }=20
    mixin(result);
}

class Container{
    size_t[] array;

    mixin arrayDelegator!(array, "opIndexAssign", "opIndex", "length");
   =20
    this( size_t[] a ){
        array =3D a:
    }

}

void main( string[] args ){
    Container c =3D new Container( [0u, 1u, 2u, 3u] );
    writeln( c[2] );
    c[2] =3D 4u;
    writeln( c[2] );
}
---------------------------------------------------------

$ ldc2 delegator.d
delegator.d(9): no identifier for declarator result
delegator.d(9): semicolon expected, not '~=3D'
delegator.d(9): Declaration expected, not '~=3D'
delegator.d(15): Declaration expected, not 'else'
delegator.d(22): Declaration expected, not 'else'
delegator.d(29): Declaration expected, not 'else'
delegator.d(32): no identifier for declarator
arrayDelegator!(instance,methods[1 .. __dollar])
delegator.d(33): unrecognized declaration

Mar 03 2012

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

On Saturday, 3 March 2012 at 16:50:45 UTC, bioinfornatics wrote:
 can w do same in D ?

alias this does that, although it does for all unknown
methods, not specific ones:

struct A {
    int[] data;
    alias data this;
}

A a;

a[0] = 10; // this works like a.data[0] = 10;


alias this also lets you pass the struct
when the member is expected:

void somethingWithArray(int[] arr) {}

A a;
somethingWithArray(a); // works, passes a.data automatically

Mar 03 2012

bioinfornatics <bioinfornatics fedoraproject.org> writes:

Le samedi 03 mars 2012 =C3=A0 19:45 +0100, Adam D. Ruppe a =C3=A9crit :
 On Saturday, 3 March 2012 at 16:50:45 UTC, bioinfornatics wrote:
 can w do same in D ?

=20
 alias this does that, although it does for all unknown
 methods, not specific ones:
=20
 struct A {
     int[] data;
     alias data this;
 }
=20
 A a;
=20
 a[0] =3D 10; // this works like a.data[0] =3D 10;
=20
=20
 alias this also lets you pass the struct
 when the member is expected:
=20
 void somethingWithArray(int[] arr) {}
=20
 A a;
 somethingWithArray(a); // works, passes a.data automatically

But when you have already a ctor ( class ) can you alias this ?

Mar 03 2012

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digitalmars.D.learn - Delegator