Easier way to add custom conforming

[ikitommi]

Currently, to add a new dynamic conforming, one needs to do the following things:

1. create a new type keyword, e.g. :color
2. create a new type-conformer, with the new type-conforming options
3. create a new Spec with the given predicate & type
4. map how the new type should be rendered into different formats, like Swagger2

Instead, we should allow inlined type definitions, something like:

(require '[spec-tools.core :as st])

(st/spec
  {:name "Color"
   :spec color?
   :conforming/json string->color
   :conforming/string string->color
   :json-schema/type "string"
   :json-schema/default "white"})

[ikitommi]

This works now in 0.6.2-SNAPSHOT:

(require '[spec-tools.core :as st])
(require '[spec-tools.conform :as conform])

(def spec
  (st/spec
    {:spec string?
     :description "a string spec"
     ::conform/json #(str %2 "-json")
     ::conform/string #(str %2 "-string")}))

(st/conform spec "kikka")
; "kikka"

(st/conform spec "kikka" st/json-conforming)
; "kikka-json"

(st/conform spec "kikka" st/string-conforming)
; "kikka-string"