Investigate a Protocol-based top-level API

[ikitommi]

currently

Options is an optional parameter to all/most public apis. Would be cleaner if there was a SchemaContext Record to hold all configuration and state for working with Schemas. Should have at least :registry and :evaluator fields.

It would implement Protocols that would cover the current public APIs and would be passed as FIRST argument to apis. Would make top-level configuration explicit:

;; using the default context
(m/schema [:and int?])

;; using explicit context
(m/schema ctx [:and int?])
 
;; explicit contexts
(def ctx (m/default-context))

(def ctx (-> (m/default-context) (assoc :evaluator (malli.sci/evaluator))))

(def ctx (m/context {:registry ..., :evaluator ...}))

why?

• Protocols yield coherent public apis, where the (optional) context is always the first argument
• Records & Protocols give type errors (cosmetic)
• Easy to extend
• Clear separation between one-time/use-case options and shared/context options:

;; ctx has things like :registry, options something for this invocation
(mg/generate ctx [:maybe int?] {:size 10, :seed 10})

draft core Protocol

(defprotocol SchemaContext
  (-schema [this ?schema])
  (-into-schema [this type properties children])
  (-registry [this])
  (-evaluator [this]))

[ikitommi]

relates to #235.