;; uniquewords.hs — count unique words using Data.Set.
;;
;; Exercises Phase 12: `import qualified Data.Set as Set`, `Set.empty`,
;; `Set.insert`, `Set.size`, `foldl`.

(define
  hk-uniquewords-source
  "import qualified Data.Set as Set\n\naddWord s w = Set.insert w s\n\nuniqueWords ws = foldl addWord Set.empty ws\n\nresult = uniqueWords [\"the\", \"cat\", \"the\", \"dog\", \"the\", \"cat\"]\n")

(hk-test
  "uniquewords.hs — unique count = 3"
  (hk-deep-force
    (hk-run (str hk-uniquewords-source "main = Set.size result\n")))
  3)

(hk-test
  "uniquewords.hs — \"the\" present"
  (hk-deep-force
    (hk-run (str hk-uniquewords-source "main = Set.member \"the\" result\n")))
  (list "True"))

(hk-test
  "uniquewords.hs — \"missing\" absent"
  (hk-deep-force
    (hk-run (str hk-uniquewords-source "main = Set.member \"missing\" result\n")))
  (list "False"))

(hk-test
  "uniquewords.hs — empty list yields empty set"
  (hk-deep-force
    (hk-run
      "import qualified Data.Set as Set\nmain = Set.size (foldl (\\s w -> Set.insert w s) Set.empty [])"))
  0)

{:fails hk-test-fails :pass hk-test-pass :fail hk-test-fail}