Using clojure.spec to parse trees

tree.cljc

(ns bonsai.tree
  (:require #?(:clj [clojure.spec.alpha :as s]
               :cljs [cljs.spec.alpha :as s])))

(s/def ::element (s/or :string string?
                       :element (s/cat :name keyword?
                                       :attrs (s/? (s/map-of keyword? any?))
                                       :children (s/* ::element))))

(s/conform ::element [:p])
;; =>
;; [:element {:name :p}]

(s/conform ::element [:p "hey!"])
;; =>
;; [:element {:name :p,
;;            :children [[:string "hey!"]]}]

(s/conform ::element [:p {:on-click println} "hey!"])
;; =>
;; [:element {:name :p,
;;            :attrs {:on-click #f
;;                    unction
;;                    [clojure.core/println]},
;;            :children [[:string "hey!"]]}]

(s/conform ::element [:p
                      {:on-click println}
                      [:span "before"] "middle" [:span "after"]])
;; =>
;; [:element {:name :p,
;;            :attrs {:on-click #function
;;                    [clojure.core/println]},
;;            :children [[:element {:name :span,
;;                                  :children [[:string "before"]]}]
;;                       [:string "middle"]
;;                       [:element {:name :span,
;;                                  :children [[:string "after"]]}]]}]