OpenEuphoria

Re: New Language

• Posted by Derek Parnell <ddparnell at bigpond.com> Sep 27, 2006
• 583 views

Mike Nelson wrote:

> I consider it a new Euphoric language. There will be no attempt at backward
> compatibiltity with Eu itself or even the Method Eu library. What I am
> envisioning
> is a language which is OOP from the ground up but has much of the essential
> power and flavor of Eu.

I fully encourage you with this idea Mike.

However, being the intrusive bastard that I am, I have a couple of suggestions
for you 

Have you considered making all members (data and methods) 'private' by default?
This makes objects a lot more robust as access from outside the class must be
explicitly granted by the class designer.

Have you considered implementing 'class properties'? These behave to the outside
as if they are data members but are actually implemented as member functions.
Each property can have multiple 'setter' and 'getter' functions.
For example:
   class Quad
      integer h
      integer l
      integer a

      procedure  ctor()
         h = 0
         l = 0
         a = 0
      end procedure

      procedure  ctor(integer pH, integer pL)
         h = pH
         l = pL
         a = h * l
      end procedure

      procedure  ctor(integer pA)
         h = floor(power(pA, 0.5))
         l = h
         a = h * l
      end procedure

      property height
         function get() 
            return h
         end function

         function get(sequence)
            return sprintf("%d", h)
         end function

         function set(integer pH)
             if pH > 0 then 
                h = pH
                a = h * l -- recalc area
             else
                throw exception("Height must be +ve")
             end if
         end function
      end property

      property length
         function get() 
            return l
         end function

         function get(sequence)
            return sprintf("%d", l)
         end function

         function set(integer pL)
             if pL > 0 then 
                l = pL
                a = h * l -- recalc area
             else
                throw exception("Length must be +ve")
             end if
         end function
      end property

      property area
         function get() 
            return a
         end function

         function get(sequence)
            return sprintf("%d", a)
         end function

      end property
end class

and used thus ...

   object f
   f = Quad(7,8)
   ? f.area -- displays 56
   f.length = 5
   ? f.area -- displays 35
   f.length += 1
   ? f.area -- displays 42
   ? f.height -- displays 7
   ? f.length -- displays 6
   ? f.h   -- Not accessible error.
   f.area = 36 -- Member is read-only

Properties add more robust abstraction without making coding onerous.

-- 
Derek Parnell
Melbourne, Australia
Skype name: derek.j.parnell