add squeaky-clean exercise (#327)

Author: bobbicodes

.gitignore

@@ -18,3 +18,5 @@ pom.xml.asc
 *.lein-plugins/
 *.lein-failures
 *.nrepl-port
+.clj-kondo
+.lsp

exercises/concept/squeaky-clean/.docs/instructions.md

@@ -0,0 +1,45 @@
+In this exercise you will implement a partial set of utility routines to help a developer
+clean up identifier names.
+
+In the 4 tasks you will gradually build up the routine `clean`. A valid identifier comprises
+zero or more letters and underscores.
+
+In all cases the input string is guaranteed to be non-nil. If an empty string is passed to the `clean` function, an empty string should be returned.
+
+Note that the caller should avoid calling the routine `clean` with an empty identifier since such identifiers are ineffectual.
+
+### 1. Replace any spaces encountered with underscores
+
+Implement the `clean` function to replace any spaces with underscores. This also applies to leading and trailing spaces.
+
+```clojure
+(clean "my   Id")
+;;=> "my___Id"
+```
+
+### 2. Replace control characters with the upper case string "CTRL"
+
+Modify the `clean` function to replace control characters with the upper case string `"CTRL"`.
+
+```clojure
+(clean "my\0Id")
+;;=> "myCTRLId"
+```
+
+### 3. Convert kebab-case to camelCase
+
+Modify the `clean` function to convert kebab-case to camelCase.
+
+```clojure
+(clean "à-ḃç")
+;;=> "àḂç"
+```
+
+### 4. Omit Greek lower case letters
+
+Modify the `clean` function to omit any Greek letters in the range 'α' to 'ω'.
+
+```clojure
+(clean "MyΟβιεγτFinder")
+;;=> "MyΟFinder"
+```

exercises/concept/squeaky-clean/deps.edn

@@ -0,0 +1,4 @@
+{:aliases {:test {:extra-paths ["test"]
+                  :extra-deps {com.cognitect/test-runner {:git/url "https://github.com/cognitect-labs/test-runner.git"
+                                                          :sha "209b64504cb3bd3b99ecfec7937b358a879f55c1"}}
+                  :main-opts ["-m" "cognitect.test-runner"]}}}

exercises/concept/squeaky-clean/src/exercism/squeaky_clean.clj

@@ -0,0 +1,35 @@
+(ns exercism.squeaky-clean
+  (:require [clojure.string :as str]))
+
+(defn escape-ctrl-char
+  "If c is a control character, outputs \"CTRL\", otherwise itself"
+  [c]
+  (if (Character/isISOControl c)
+    "CTRL" c))
+
+(defn escape-ctrl [s]
+  (apply str (map escape-ctrl-char s)))
+
+(defn camelize [s]
+    (let [words (str/split s #"-")]
+      (if (str/includes? s "-")
+      (str/join "" (cons (first words)
+                         (cons (str/upper-case (ffirst (rest words)))
+                               (rest (first (rest words))))))
+    s)))
+
+(defn letters [s]
+  (apply str (filter #(or (Character/isLetter %)
+                        (= \_ %))
+                     s)))
+
+(defn clean-greek [s]
+  (apply str (filter #(not (<= 945 (int %) 969)) s)))
+
+(defn clean [s]
+  (-> s
+       (str/replace " " "_")
+       camelize
+      escape-ctrl
+      letters
+      clean-greek))

exercises/concept/squeaky-clean/test/exercism/squeaky_clean_test.clj

@@ -0,0 +1,30 @@
+(ns exercism.squeaky-clean-test
+  (:require [clojure.test :refer [deftest testing is]]
+            exercism.squeaky-clean))
+
+(deftest clean-single-letter
+  (is (= "A" (exercism.squeaky-clean/clean "A"))))
+
+(deftest clean-clean-string
+  (is (= "àḃç" (exercism.squeaky-clean/clean "àḃç"))))
+
+(deftest clean-string-with-spaces
+  (is (= "my___Id" (exercism.squeaky-clean/clean "my   Id"))))
+
+(deftest clean-string-with-control-char
+  (is (= "myCTRLId" (exercism.squeaky-clean/clean "my\u0000Id"))))
+
+(deftest clean-string-with-no-letters
+  (is (= "" (exercism.squeaky-clean/clean "😀😀😀"))))
+
+(deftest clean-empty-string
+  (is (= "" (exercism.squeaky-clean/clean ""))))
+
+(deftest convert-kebab-to-camel-case
+  (is (= "àḂç" (exercism.squeaky-clean/clean "à-ḃç"))))
+
+(deftest omit-lower-case-greek-letters
+  (is (= "MyΟFinder" (exercism.squeaky-clean/clean "MyΟβιεγτFinder"))))
+
+(deftest combine-conversions
+  (is (= "_AbcĐCTRL" (exercism.squeaky-clean/clean "9 -abcĐ😀ω\0"))))