function can be called as msgbox(abc(a,b),"OK") 1+2+3*5 msgbox($_) //display 18 if (a==b) 2 else 3 //work fine def fact(n) if (n==1) 1 else n*fact(n-1) end msgbox(fact(5)) //work fine display 120 ExprParser move to Interpreter. Single line if statement. ++/-- like C languag