Why to have properties to sort or duplicate arrays ?

[doob]

Pierre Renié Wrote:

> Daniel Giddings Wrote:
> > if you make a method clean, it can act like a "property" even if it 
> > doesn't return anything as it is a syntax "shortcut" if you like:
> > 
> > import std.stdio;
> > 
> > class C
> > {
> >      void clean()
> >      {
> >          writefln( "C.clean" );
> >      }
> > }
> > 
> > void main()
> > {
> >      C c = new C;
> >      c.clean; // works, but is bad programming style
> >               // c.clean() has a clearer meaning
> > }
> > 
> > this doesn't mean you should remove this feature (or any other) because 
> > bad programming style or design obfuscates the meaning of the code.
> 
> Why not to add a keyword "prop" ?
> Like in this code :
> 
> class C
> {
>      void clean()//This is a method
>      {
>          writefln( "C.clean" );
>      }
> 
>      prop int somevalue()//This is a property
>      {
>          return 1;
>      }
> }
> 
> void main()
> {
>      C c = new C;
>      c.clean; // won't work because there is no keyword "prop" (=> compile error)
>      c.clean(); //correct
>      int i = c.somevalue; // correct because this is a property
> }
> 
> I want this because I want the compiler to prevent me from making mistakes.


I think it would be good to add a "property" keyword and maybe also "get" and "set". I think also would be nice to add a feature from ruby that i think works something like this:

Ruby code:
class C
{
attr_reader :variable1, :variable2, :variable3
}

and this will create a private variable and a read property. And ther is also "attr_writer" to create a write property. In D this could look something like this

D code:
class C
{
    property
    {
        int variable1;
        char[] variable2;
        int variable3;
    }
}

This would create a private variable and a get and set property method. 
Then you could also write like this:

D code:
class C
{
    private property
    {
        int variable1;
        char[] variable2;
        int variable3;
    }
}

to make the get and set property methods private. 
You could write like this:

D code:
class C
{
    get
    {
        int variable1;
        char[] variable2;
        int variable3;
    }
}

to only make a private variable and a get property method. 
The get and set methods would be public as default and the variable would always be private. I think it would be great if you could write as i have described above because when you want a private variable and get and set methods that only sets or returns the value. If you would like to do something in the methods it could look like this:

D code:
class C
{
    private int variable_;
    
    public get int variable ()
    {
        return variable_;
    }

    public set int variable (int variable)
    {
        if (variable > 3)
            return variable_ = variable;
    }
}