Kawa has the usual syntax for decimal integers.
Addition, subtraction, and mutliplication
are written using the usual +,
-, and *,
but these are all prefix functions that take a variable number of arguments:
(+ 1 2 3) ⇒ 6 (- 10 3 4) ⇒ (- (- 10 3) 4) ⇒ 3 (* 2 -6) ⇒ -12
Kawa has arbitrary-precision integers.
Let us implement the factorial function. Type in the following (we’ll look at the syntax shortly):
#|kawa:1|# (define (factorial x) #|(---:2|# (if (< x 1) 1 #|(---:3|# (* x (factorial (- x 1)))))
(The prompt changes to indicate a continuation line.)
This binds the name factorial
to new function, with formal parameter x.
This new function is immediately compiled to Java bytecodes,
and later a JIT compiler may compile it to native code.
A few tests:
#|kawa:4|# (list (factorial 3) (factorial 4)) (6 24) #|kawa:5|# (factorial 30) 265252859812191058636308480000000