Procedural programming

Local variables:

(let x 5
  (print x))

(let* (x 5
       y (+ x 1))
  (print y))

For loops work with generators like (range):

(for i (range 10)
  (print i))

Generators are functions which can be called repeatedly until they return nil. The values are wrapped in cons cells to allow generators to generate nil values:

(let generator (range 1)
  (print (generator))   # (0)
  (print (generator)))  # nil

The (iter) generic can be implemented to create generators that iterate over values:

(for x (iter '(1 2 3))
  (print x))

Code blocks can be written as a single expression using (begin):

(begin
  (print "message 1")
  (print "message 2"))

(when) and (cond) can also be used for conditionals:

(when (> x 4)
  (print "x > 4"))

(cond
  (> x 3) (print "> 3")
  (< x 2) (print "< 2")
  true (print "x is 2 or 3"))