Re: [Objectscript-users] Addition to OScript syntax

[Rob C. <ro...@ti...>]

the qualified "this" (and "super") syntax is introduced in =20
oscript-2.10, which I've unfortunately not had time to upload to =20
sf.net yet.  (Sorry.. been very busy with my day job.)  But you can =20
see it in the SVN repository (https://objectscript.kicks-ass.org/=20
svn).  I'll try and make a 2.10.1 to upload this weekend after I've =20
had a chance to merge Lysander's patches.

Anyways, the way qualified "this" works is I added to Scope a getThis=20
(Value) method.  So "Foo.this" is implemented as "currentScope.getThis=20=

(Foo)".  The way it works is that in FunctionScope:

   public Value getThis( Value val )
   {
     if( fxn =3D=3D val.unhand() )
       return new OThis(this);
     return super.getThis(val);
   }

so the nearest enclosing function-scope for the function "Foo" will =20
return the "this".

So to do what you describe, in BasicScope (where mixin is handled), =20
it would have to do something like:

   public Value getThis( Value val )
   {
     for( int i=3D0; i<mixins.length; i++ )
     {
       if( mixins[i] instanceof Scope )
       {
         if( mixins[i].bopInstanceOf(val) )
           return mixins[i];
       }
     }
     return super.getThis(val);
   }


------

background notes:

in Scope, the base class for all scopes (FunctionScope, BasicScope, =20
etc):

   public Value getThis( Value val )
   {
     return previous.getThis(val);
   }

so the default behavior is to pass the request for "this" up the =20
scope chain.




On Dec 3, 2005, at 4:17 AM, <ar...@va...> wrote:

> I'm glad you understand what i mean. I was not sure if it was clearly
> stated below. I have based this on the LPC language created by Lars =20=

> Pensj=F6
> for his LP-MUD. It supports the "::" to point at specific inherited
> objects. It also uses "::method()" as the "super" qualifier used in =20=

> Java.
>
> But i think it is just a matter of syntax choice on how to =20
> implement this.
> I think what you proposed will get the job done as well.
>
> In what version of OScript did you implement the qualified "this" =20
> syntax?
>
>
>
>> Hmm, I've recently just added a qualified "this" syntax, for example
>> "Foo.this"... the way it is currently supported is "Foo.this"
>> evaluates to the nearest "this" which is a "Foo".  As in:
>>
>> function Outer()
>> {
>>    private var a =3D 1;
>>    function Inner()
>>    {
>>      private var a =3D 2;
>>
>>      public function test()
>>      {
>>        private var a =3D 3;
>>
>>        {
>>          var a =3D 4;
>>
>>          writeln("a: " + a);
>>          writeln("test.this.a: " + test.this.a);
>>          writeln("this.a: " + this.a);
>>          writeln("Inner.this.a: " + Inner.this.a);
>>          writeln("Outer.this.a: " + Outer.this.a);
>>        }
>>      }
>>    }
>> }
>>
>> maybe it would sense to support mixin's in a similar way, so you
>> could do something like "A.this.print()"?
>>
>> thoughts?
>>
>>
>> On Dec 2, 2005, at 6:49 AM, <ar...@va...> wrote:
>>
>>> Rob,
>>>
>>> Is it difficult to add the following to the OScript syntaxt:
>>>
>>> function A() {
>>>   public function print() {}
>>> }
>>>
>>> function B() {
>>>   mixin new A();
>>>
>>>   public function print() {
>>>     A::print();
>>>     ^^^^^^^^^^^
>>>     // do other print stuff
>>>   }
>>> }
>>>
>>> "::" means in this case that you specifically point to the object
>>> "A" and
>>> call its print method. I don't think that this is a difficult
>>> addition to
>>> the syntaxt, but i'm completely unknown to JavaCC and how you used
>>> it in
>>> OScript.
>>>
>>> Maybe you can point me in some direction to have this included.
>>>
>>> thank you very much.
>>>
>>> Regards,
>>>
>>> Arjen van Efferen
>>>
>>>
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>>
>> -- Rob
>>
>> ____________________
>> CONTACT INFORMATION:
>> email:    ro...@ti...
>> IM:   rob@sandjabber
>> desk: 1 858 552 2946
>> cell: 1 619 300 9661
>>
>>
>>
>>
>


____________________
CONTACT INFORMATION:
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IM:   rob@sandjabber
desk: 1 858 552 2946
cell: 1 619 300 9661