Module Checkit {
      \\ functions can shange by using a newer definition
      \\ function Multiply is local, and at the exit of Checkit, erased.
      Function Multiply (a, b) {
            =a*b
      }
      Print Multiply(10, 5)=50

      Function Multiply {
            =Number*Number
      }

      Print Multiply(10, 5)=50

      Function Multiply {
            If not match("NN") Then Error "I nead two numbers"
            Read a, b
            =a*b
      }
      Print Multiply(10, 5)=50
      Function Multiply {
            Read a as long, b as long
            =a*b
      }
      Z=Multiply(10, 5)
      Print Z=50, Type$(Z)="Long"
      Function Multiply(a as decimal=1, b as decimal=2) {
            =a*b
      }
      D=Multiply(10, 5)
      Print D=50, Type$(D)="Decimal"
      D=Multiply( , 50)
      Print D=50, Type$(D)="Decimal"
      D=Multiply( 50)
      Print D=100, Type$(D)="Decimal"
      \\ by reference plus using type
      Function Multiply(&a as decimal, &b as decimal) {
            =a*b
            a++
            b--
      }
      alfa=10@
      beta=20@
      D=Multiply(&alfa, &beta)
      Print D=200, alfa=11,beta=19, Type$(D)="Decimal"
      \\ Using Match() to identify type of items at the top of stack
      Function MultiplyALot {
            M=Stack
            While Match("NN") {
                  mul=Number*Number
                  Stack M {
                        Data mul  ' at the bottom
                  }
            }
            =Array(M)
      }

      K=MultiplyALot(1,2,3,4,5,6,7,8,9,10)
      N=Each(K)
      While N {
            Print Array(N),     ' we get 2  12   30   56   90
      }
      Print
}
Checkit