From: Bill Kelly <billk@...>
Date: 2001-04-23T06:24:53+09:00
Subject: [ruby-talk:14034] Re: Comments in code (was Re: From Guido, with love...)


From: "Dennis Decker Jensen" <dennisdecker@mail.tele.dk>

> Regarding implementation language: I think I would need a lot more
> "helpful comments" if I were to code in Forth or Assembler... :-)

What!??  Surely nothing could be as immediately and transparently
obvious as:

    DUP >R 2* 1+
    FOR R@ I - ABS DUP *  R@ 2* 1+
      FOR  R@ I - ABS DUP * OVER +
        R@ 1- DUP *  R@ DUP * WITHIN
        IF ASCII * ELSE BL THEN EMIT
      NEXT CR DROP
    NEXT R> DROP

;-)  Okay, here's my attempt at hopefully a maximally-readable ruby
implementation.  (But I'm a ruby novice so any improvements would be
most welcome!)

class Circle

    def Circle.draw(radius)
        (-radius..radius).each do |y|
            (-radius..radius).each do |x|
                if pointOnCircle? x, y, radius then
                    print '*'
                else
                    print ' '    
                end
            end
            print "\n"
        end
    end

    def Circle.pointOnCircle?(x, y, radius)
        Integer(dist x, y) == radius
    end
    
    def Circle.dist(x, y)
        Math.sqrt(x**2 + y**2)
    end

end


P.S. I just had a thought as to how to comment the Forth version
at the level of intent:

                     DUP >R
                2* 1+       FOR R@
            I - ABS            DUP *  R@
           2* 1+                FOR  R@ I
       - ABS DUP                 * OVER +
       R@ 1- DUP                 *  R@ DUP
         * WITHIN               IF ASCII *
           ELSE BL            THEN EMIT
               NEXT CR      DROP NEXT
                     R> DROP

;-)

Bill