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(define-module (hasher dictionary)
#:export (create-dictionary
dict-occur-ref
dict-keys-ref
dict-values-ref))
(define (create-dictionary lst)
(dictionary-helper (make-hash-table) lst))
(define (dictionary-helper dict rest)
"Recursively adds words to DICT."
(if (null? rest)
dict
(begin
(dict-inc-word dict (car rest))
(dictionary-helper dict (cdr rest)))))
(define (dict-inc-word dict e)
"Inserts word E into the DICT, using E
as a key and the running total of occurances
as the value."
(hashq-set!
dict e (1+ (dict-occur-ref dict e))))
(define (dict-occur-ref dict e)
"A wrapper for hashq-ref. Returns '0' if an element
is not present, rather than '#f'."
(let ((occur (hashq-ref dict e)))
(if occur occur 0)))
(define (dict-keys-ref dict)
"Returns a list of all words in the dictionary."
(map car (hash-map->list cons dict)))
(define (dict-values-ref dict)
"Sums up the total number of occurances for all words."
(apply + (map cdr (hash-map->list cons dict))))
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