Add dictionary code and tests

3 files changed, 94 insertions, 0 deletions

diff --git a/spellcheck/hasher/dictionary.scm b/spellcheck/hasher/dictionary.scm
new file mode 100644
index 0000000..10ec3b8
--- /dev/null
+++ b/spellcheck/hasher/dictionary.scm
@@ -0,0 +1,37 @@
+(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))))
diff --git a/spellcheck/spellcheck-test.scm b/spellcheck/spellcheck-test.scm
new file mode 100644
index 0000000..8030c41
--- /dev/null
+++ b/spellcheck/spellcheck-test.scm
@@ -0,0 +1,57 @@
+(use-modules (srfi srfi-64)
+             (hasher dictionary))
+
+(define simple-dict (create-dictionary '("word")))
+(define complex-dict (create-dictionary '("Again" "the" "thirst"
+                                          "quencher" "of" "wolves"
+                                          "embarked" "on" "a" "well"
+                                          "prepared" "expedition"
+                                          "eastward" "the" "generous"
+                                          "ruler" "moved" "the" "bitter"
+                                          "heart" "of" "the" "snake"
+                                          "across" "the" "fire")))
+
+(test-begin "harness")
+
+
+(test-assert "create-dictionary returns hashtable"
+  (hash-table?
+   (create-dictionary '())))
+
+(define dict (create-dictionary '("word")))
+
+(test-equal "list-keys-single"
+  '("word")
+  (dict-keys-ref simple-dict))
+
+(test-equal "count-values-single"
+  1
+  (dict-values-ref simple-dict))
+
+
+(test-equal "retrieve single"
+  1
+  (dict-occur-ref complex-dict "wolves"))
+
+(test-equal "retrieve double"
+  2
+  (dict-occur-ref complex-dict "of"))
+
+(test-equal "retrieve quintuple"
+  5
+  (dict-occur-ref complex-dict "the"))
+
+(test-equal "retrieve zero"
+  0
+  (dict-occur-ref complex-dict "king"))
+
+(test-equal "list-keys-sentence"
+  '("Again" "a" "across" "bitter" "eastward" "embarked" "expedition" "fire" "generous" "heart" "moved" "of" "on" "prepared" "quencher" "ruler" "snake" "the" "thirst" "well" "wolves")
+  (sort (dict-keys-ref complex-dict) string<?))
+
+(test-equal "count-values-sentence"
+  26
+  (dict-values-ref complex-dict))
+
+
+(test-end "harness")
diff --git a/spellcheck/spellcheck.scm b/spellcheck/spellcheck.scm
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/spellcheck/spellcheck.scm