Simplest would be to do something like this:
(def Schema (s/cond-pre s/Int (s/constrained clojure.lang.Reduced
#(integer? @%))))
although this doesn't allow you to use the schema in both places. The right
way would be to make a new `Reduced` schema:
(defrecord Reduced [schema]
schema.core/Schema
(spec [this]
(schema.spec.collection/collection-spec
(schema.spec.core/precondition this #(instance? clojure.lang.Reduced
%) #(list 'instance? clojure.lang.Reduced %))
reduced
[(schema.spec.collection/one-element true schema (fn [item-fn r]
(item-fn @r) nil))]
(clojure.core/fn [_ xs _] (reduced (first xs)))))
(explain [this] (list 'reduced-val (schema.core/explain schema))))
(defn reduced-val [schema] (Reduced. schema))
(defn possibly-reduced [schema]
(s/cond-pre (reduced-val schema) schema))
(s/validate [(possibly-reduced s/Int)] [1 (reduced 1)])
Best,
Jason
On Friday, April 1, 2016 at 6:17:48 AM UTC+5:45, JvJ wrote:
>
>
> When using functions with schema type signatures for reduce, I run into
> output schema errors whenever I try to short-circuit the reducing operation
> by wrapping the return value in reduced. How can I modify the type
> signature so that it accepts output values of types A and (reduced A)?
>
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