Clojurians Log v2

@charles.fourdrignier, well, yes and no. It compiles then, but it still doesn’t work. The following compiles, but the expected output is not useful, and not what’s expected from a recursive spec. (see output from explain and conform)

(require '[clojure.alpha.spec :as s])

(def expr '(+ (+ 1 (* 2 "three")) 200))

(defn operator? [x] (#{'+ '- '* '/} x))

(s/def ::operator operator?)
(s/def ::operand int?)

(s/def ::expr any?)
(s/def ::expr
  (s/or :operand ::operand
        :expr (s/cat :operator ::operator
                     :left ::expr
                     :right ::expr)))

(s/explain ::expr expr) ;; success, but shouldn't be if recursive specs works.

(s/conform ::expr expr)
;; result 
[:expr {:left (+ 1 (* 2 "three")) :operator + :right 200}]

Hmm… But this actually seems to work in “spec 1”, (clojure 1.10.1) but not in spec 2.

(require '[clojure.spec.alpha :as s])

(def bad-expr '(+ (+ 1 (* 2 "three")) 200))
(def expr '(+ (+ 1 (* 2 3)) 200))

(defn operator? [x] (#{'+ '- '* '/} x))

(s/def ::operator operator?)
(s/def ::operand int?)

(s/def ::expr
  (s/or :operand ::operand
        :expr (s/cat :operator ::operator
                     :left ::expr
                     :right ::expr)))

(s/valid? ::expr bad-expr)  ; false
(s/explain ::expr bad-expr) ;
(s/conform ::expr bad-expr) ; :clojure.spec.alpha/invalid

(s/valid? ::expr expr)   ; true
(s/explain ::expr expr)  ; success
(s/conform ::expr expr)

There are some known issues with eager spec dereferencing in spec 2

Ah, ok. Thanks @alexmiller.