Recursive Schemas Impl

[ikitommi]

Displaces impl from #117, which will remain a place to discuss & history. FIxs #20 .

• new m/Schema method -children to get child schemas instances too
• :multi implements m/MapSchma
• new m/RefSchma protocol with the following impls:
  • :ref - a lazy reference, enabling recursion
  • :schema, like m/schema (entity) but in data, eager
  • malli.core/schema, eager schema (value) ref, used internally. if no properties and child is a qualified keyword, derived form from the child
• support for local :registry in any element
• validators, explainers etc are moved from schema creation to actual m/Schema methods, to support laziness
• m/-distance and m/-lookup helpers
• m/from-map-syntax works with non-map child's (enums, refs)
• updated README (local registry, recursive schemas)

TODO

• :schema for non-lazy references (retains original information)
• local recursion using :id
• local mutual recursion using :registy
• new element to ensure local registries as data
• ambiguity rules
• ensure it's done right

Current syntax:

(testing "recursion limiting"
  (are [schema]
    (is (every? (partial m/validate schema) (mg/sample schema {:size 1000})))

    ;; maybe
    [:schema {:registry {::rec [:maybe [:ref ::rec]]}}
     ::rec]

    ;; maps
    [:schema {:registry {::rec [:map [:rec {:optional true} [:ref ::rec]]]}}
     ::rec]

    ;; or
    [:schema {:registry {::tuple [:tuple boolean? [:ref ::or]]
                         ::or [:or int? ::tuple]}}
     ::or]

    ;; multi
    [:schema {:registry {::multi
                         [:multi {:dispatch :type}
                          [:int [:map [:type [:= :int]] [:int int?]]]
                          [:multi [:map [:type [:= :multi]] [:multi [:ref ::multi]]]]]}}
     [:ref ::multi]]))

Initial Syntax:

(support for local recursion removed)

[ikitommi]

Recursive schema resolution is too eager now:

(m/form
  [:and
   {:registry {::ping ::pong2
               ::pong2 ::pong
               ::pong [:and pos-int?]}}
   ::ping])
;[:and {:registry {:user/ping [:and pos-int?]
;                  :user/pong2 [:and pos-int?]
;                  :user/pong [:and pos-int?]}} 
; [:and pos-int?]]

, should retain the pointer information.

[rschmukler]

Awesome! Left a super nitpicky comment that really doesn't warrant any changes. Code looks really nice, as always.

[rschmukler]

Perhaps this is better filed as a bug with them, but just worth noting that the "prime" convention isn't well supported in some editors' understanding of the clojure grammar. Emacs will attempt to convert options' into options ' causing the expression to rebind options to the quoted expression '(-recursion-options schema options).