iota

Conformance: SketchyLISP Extension

Purpose: Generate sequences of numbers.

Arguments:
l - lower limit of sequence
h - upper limit of sequence

Model:

(define (iota l h)
  (cond ((= l h) (list l))
    (else (cons l (iota (+ l 1) h)))))

Implementation:

(define (iota l h)
  (letrec
    ((j
       (lambda (x r)
         (cond ((= x l) (cons l r))
           (else (j (- x 1) (cons x r)))))))
    (cond ((> l h)
        (bottom '(iota: bad range)))
      (else (j h '())))))

Example:

(iota 1 10) 
=> (1 2 3 4 5 6 7 8 9 10)

See also:
sum, product.