4 ms·

Can you elaborate a bit on your own "types"? I am very interested and intrigued.

• badsavage 8y ago
  Yes, I could show you a simple example: Let's create our own 78 digits long string type: (def hex-digit (set "0123456789")) (defn hex-digit? [x] (contains? hex-digit x)) (defn hex-str? [s] (every? hex-digit? (seq s))) (s/def ::hash (s/and hex-str? #(= (count %) 78))) ::hash is now registered, now we go to the REPL: (s/valid? ::hash "23179372") ;;=> false (s/valid? ::hash "nope93721907914920047210715459933122004671648400678953445710500236944435987060") ;;=> false (s/valid? ::hash "231793721907914920047210715459933122004671648400678953445710500236944435987060") ;;=> true That's cool, but we want to generate too: (defn hex-str-gen [n] (let [digit (g/elements hex-digit)] (g/fmap clojure.string/join (g/vector digit n)))) (s/def ::hash (s/with-gen (s/and hex-str? #(= (count %) 78)) #(hex-str-gen 78))) We extended our ::hash spec with a generator function, so we can do this now: (g/generate (s/gen ::hash)) ;;=> "310584715385467847758653938894742415543975445356609397864862925839413265904779" (+ Pro tip: you could spec functions too) Learn more about spec here: https://clojure.org/guides/spec https://clojure.org/guides/spec
  • pvinis 8y ago
    Very interesting! Thank you!
  • dpg23 8y ago
    I don't fully get the syntax (I've had a tiny bit of Scheme experience) but wow that's awesome.