Add elisp/word-count

elisp/word-count/README.md

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+# Word Count
+
+Given a phrase, count the occurrences of each word in that phrase.
+
+For example for the input `"olly olly in come free"`
+
+```plain
+olly: 2
+in: 1
+come: 1
+free: 1
+```
+
+## Source
+
+This is a classic toy problem, but we were reminded of it by seeing it in the Go Tour.
+
+## Submitting Incomplete Solutions
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.

elisp/word-count/word-count-test.el

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+;;; word-count-test.el --- Tests for word-count (exercism)
+
+;;; Commentary:
+
+;;; Code:
+
+(load-file "word-count.el")
+
+
+(defun equal-assoc (a b)
+  (equal (sort a #'(lambda (a b) (not (string< (car a) (car b)))))
+         (sort b #'(lambda (a b) (not (string< (car a) (car b)))))))
+
+
+(ert-deftest no-words-test ()
+  (should (equal-assoc (word-count "")
+                       nil)))
+
+
+(ert-deftest count-one-word-test ()
+  (should (equal-assoc (word-count "word")
+                       '(("word" . 1)))))
+
+
+(ert-deftest count-one-of-each-word-test ()
+  (should (equal-assoc (word-count "one of each")
+                       '(("each" . 1)
+                         ("of" . 1)
+                         ("one" . 1)))))
+
+
+(ert-deftest multiple-occurrences-of-a-word-test ()
+  (should (equal-assoc (word-count "one fish two fish red fish blue fish")
+                       '(("blue" . 1)
+                         ("red" . 1)
+                         ("two" . 1)
+                         ("fish" . 4)
+                         ("one" . 1)))))
+
+
+(ert-deftest ignore-punctuation-test ()
+  (should (equal-assoc (word-count "car : carpet as java : javascript!!&@$%^&")
+                       '(("javascript" . 1)
+                         ("java" . 1)
+                         ("as" . 1)
+                         ("carpet" . 1)
+                         ("car" . 1)))))
+
+
+(ert-deftest include-numbers-test ()
+  (should (equal-assoc (word-count "testing, 1, 2 testing")
+                       '(("2" . 1)
+                         ("1" . 1)
+                         ("testing" . 2)))))
+
+
+(ert-deftest normalize-case-test ()
+  (should (equal-assoc (word-count "go Go GO Stop stop")
+                       '(("stop" . 2)
+                         ("go" . 3)))))
+
+
+(provide 'word-count)
+;;; word-count-test.el ends here

elisp/word-count/word-count.el

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+;;; word-count.el --- word-count Exercise (exercism)
+
+;;; Commentary:
+
+;;; Code:
+
+(defun extract-words (s)
+"Extract lowercased words from S.
+Splits on whitespace, removes non alphanumeric characters."
+  (split-string (replace-regexp-in-string "[^[:alnum:]_-]" " " (downcase s))))
+
+(defun word-count (s)
+"Return an alist word count of words in S."
+  (let ((word-count ()))
+    (dolist (w (extract-words s) word-count)
+      (let ((entry (assoc w word-count)))
+        (if entry (cl-incf (cdr entry))
+          (push (cons w 1) word-count))))))
+
+(provide 'word-count)
+;;; word-count.el ends here