guile-examples/hash-table/example.scm

(use-modules (srfi srfi-1))

(define (make-dumbhash size)
  "Make a dumb hash table: an array of buckets"
  (make-array '() size))

(define* (dumbhash-ref dumbhash key #:optional (default #f))
  "Pull a value out of a dumbhash"
  (let* ((hashed-key (hash key (array-length dumbhash)))
         (bucket (array-ref dumbhash hashed-key)))
    (or (find (lambda (x) (equal? (car x) key))
              bucket)
        default)))

(define (dumbhash-set! dumbhash key val)
  "Set a value in a dumbhash"
  (let* ((hashed-key (hash key (array-length dumbhash)))
         (bucket (array-ref dumbhash hashed-key)))
    ;; Only act if it's not already a member
    (if (not (find (lambda (x) (equal? (car x) key))
                   bucket))
        (array-set! dumbhash
                    ;; extend the bucket with the key-val pair
                    (cons (cons key val) bucket)
                    hashed-key))))