Suppose you're defining a data type circle with three parts: a
center of type posn, a radius of type number, and
a color of type symbol (e.g. 'red,
'blue, etc.)
Since you've already written function contracts for the functions given by
your define-struct, you know that there's a function named
make-circle that takes in a posn, a
number, and a symbol in that order, and returns a
circle. So to create an example of the circle
type, simply call this function on arguments of the appropriate types:
(make-circle (make-posn 3 4) 5 'red)Note that since the first parameter was a
posn, we needed to
call make-posn to get an example of the posn type
which we could then pass into make-circle.