Convert Clojure Specs to Malli schemas at runtime.
dev.kwill/specalli {:mvn/version "1.0.1"}The library exposes a single API namespace kwill.specalli with the mallize function. The function takes a Clojure
Spec form and returns a Malli schema. A handful of examples are presented below. A more comprehensive set of examples
can be found in the test namespace kwill.specalli-test.
(require '[kwill.specalli :as specalli])
(specalli/mallize `double?)
=> :double
(specalli/mallize (s/double-in :min 1 :max 10))
=> [:double {:min 1, :max 10}]
(specalli/mallize
(s/cat
:int (s/+ int?)
:str (s/? string?)
:m (s/* map?)))
=> [:catn [:int [:+ :int]] [:str [:? :string]] [:m [:* :map]]]s/keys*s/&
Malli does not support merging :map and :multi yet (see #493). If you
pass a Spec that tries to merge those, the library will return a schema that appears to support it, but it will not
work.
Certain Spec definitions are difficult to impossible to convert to a Schema at runtime without resolving a symbol or
evaluating a form. As such, dynamic conversions of those Specs are not possible in ClojureScript. A comprehensive list
of forms requiring symbol resolution or eval capabilities are listed below.
In some places, Spec will accept a symbol as the input to a Spec's option value. For example, you can use a top-level
var as the :max value with s/double-in.
(def the-max 10)
(s/double-in :max the-max)Or you can even use a form.
(s/double-in :max (* 1024 8)) Unfortunately, we need to pass the actual value to the Malli schema option value. This requires us to resolve or eval the option value. Specs defined with a var or form will not work in ClojureScript.
Spec supports specifying an enumeration by defining a spec as a var pointing to a set literal. To convert a Spec at
runtime, we must know if the symbol returned by the Spec's form is a set. We cannot do this dynamic resolution in
ClojureScript, so we fall back to a :fn schema.
(def enum-set #{"a"})
=> #'user/enum-set
(s/def ::enum my-set)
=> :user/enum
(s/form ::enum)
=> user/my-set
;; In CLJS only:
(specalli/mallize ::enum)
=> [:fn #{"a"}]Multispecs are defined using multimethods which are defined at runtime. We need to resolve the multimethod symbol to a
callable function, enumerate its methods, and execute the multimethod for each dispatch to create the :multi schema.