Spec-musings

(defn -bool?
  [x]
  (cond
    (boolean? x) x
    (string? x) (case x
                  ("true" "TRUE" "t" "T") true
                  ("false" "FALSE" "f" "F") false
                  :clojure.spec/invalid)
    :else :clojure.spec/invalid))

(def bool? 
  (s/with-gen (s/conformer -bool? identity)
    (constantly (gen/boolean))))

(s/def ::b bool?)

(s/def ::bmv (s/cat :b ::b))

(s/conform ::bmv ["true"])
;; => {:b true}

(s/unform ::bmv (s/conform ::bmv ["true"]))
;; => (true)

(s/unform ::bmv (s/conform ::bmv ["foo"]))
;; =>  contains? not supported on type: clojure.lang.Keyword

(defn coerce
  [spec data]
  (let [conformed (s/conform spec data)]
     (if (= :clojure.spec/invalid conformed)
       conformed
       (s/unform spec conformed))))

(coerce ::bmv ["t"])
;; => (true)

(s/valid? ::bmv (coerce ::bmv ["t"]))
;; => true

(coerce ::bmv ["foo"])
;; => :clojure.spec/invalid