Cadence SKILL - Examples

Examples

Here are some examples of SKILL.

First, a basic “Hello world”:

println("Hello, world!")

SKILL supports tail call optimization, if it is explicitly enabled. Here is a tail recursive version of factorial which requires no stack space for the recursion if optimizeTailCall is enabled.

(sstatus optimizeTailCall t) (defun factorial (n) (flet ((repeat (n factorial) (if (plusp n) (repeat (sub1 n) n * factorial)) factorial))) (repeat n 1)))

The following definition is a more idiomatic iterative definition.

(defun factorial (n) (let ((answer 1)) (for i 2 n answer = answer * i) answer)))

This example shows how variables are assigned and scoped, using = and let, respectively:

procedure( swap let( ((a 1) (b 2)) c = a a = b b = c printf("%d %d %d\n" a b c) ) )

The variables a and b are scoped within the let function, but variable c is not. As a result, c becomes a global variable that can be accessed without the scope of the swap function. Here is what happens when swap is executed and a, b and c are then printed:

> swap 2 1 1 t > a *Error* toplevel: undefined variable - a > b *Error* toplevel: undefined variable - b > c 1