[Forth] Derivative "Eight"

[Joe Horn]

Wow, 8th looks so close to RPL that learning it should be easy for RPL afficionados, especially those who have ever dabbled with System RPL. Check out this sample of 8th code:

Code:

\ Find the sum of all the multiples of 3 or 5 below 1000.

with: n
: div? \ n m -- f
  mod not ;

: sum-multiples \ sum x -- sum'
    dup 3 div?
    over 5 div?  or 
  if + else drop then ;

0 ' sum-multiples 3 999 loop . cr bye