analyzer.clj

;   Copyright (c) Rich Hickey. All rights reserved.
;   The use and distribution terms for this software are covered by the
;   Eclipse Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php)
;   which can be found in the file epl-v10.html at the root of this distribution.
;   By using this software in any fashion, you are agreeing to be bound by
;   the terms of this license.
;   You must not remove this notice, or any other, from this software.

(set! *warn-on-reflection* true)

(ns cljs.analyzer
  (:refer-clojure :exclude [macroexpand-1])
  (:require [clojure.java.io :as io]
            [clojure.string :as string]
            [cljs.tagged-literals :as tags])
  (:import java.lang.StringBuilder))

(declare resolve-var)
(declare resolve-existing-var)
(declare warning)
(def ^:dynamic *cljs-warn-on-undeclared* false)
(declare confirm-bindings)
(declare ^:dynamic *cljs-file*)

;; to resolve keywords like ::foo - the namespace
;; must be determined during analysis - the reader
;; did not know
(def ^:dynamic *reader-ns-name* (gensym))
(def ^:dynamic *reader-ns* (create-ns *reader-ns-name*))

(defonce namespaces (atom '{cljs.core {:name cljs.core}
                            cljs.user {:name cljs.user}}))

(defn reset-namespaces! []
  (reset! namespaces
    '{cljs.core {:name cljs.core}
      cljs.user {:name cljs.user}}))

(defn get-namespace [key]
  (@namespaces key))

(defn set-namespace [key val]
  (swap! namespaces assoc key val))

(def ^:dynamic *cljs-ns* 'cljs.user)
(def ^:dynamic *cljs-file* nil)
(def ^:dynamic *cljs-warn-on-redef* true)
(def ^:dynamic *cljs-warn-on-dynamic* true)
(def ^:dynamic *cljs-warn-on-fn-var* true)
(def ^:dynamic *cljs-warn-fn-arity* true)
(def ^:dynamic *cljs-warn-fn-deprecated* true)
(def ^:dynamic *cljs-warn-protocol-deprecated* true)
(def ^:dynamic *unchecked-if* (atom false))
(def ^:dynamic *cljs-static-fns* false)
(def ^:dynamic *cljs-macros-path* "/cljs/core")
(def ^:dynamic *cljs-macros-is-classpath* true)
(def  -cljs-macros-loaded (atom false))

(defn load-core []
  (when (not @-cljs-macros-loaded)
    (reset! -cljs-macros-loaded true)
    (if *cljs-macros-is-classpath*
      (load *cljs-macros-path*)
      (load-file *cljs-macros-path*))))

(defmacro with-core-macros
  [path & body]
  `(do
     (when (not= *cljs-macros-path* ~path)
       (reset! -cljs-macros-loaded false))
     (binding [*cljs-macros-path* ~path]
       ~@body)))

(defmacro with-core-macros-file
  [path & body]
  `(do
     (when (not= *cljs-macros-path* ~path)
       (reset! -cljs-macros-loaded false))
     (binding [*cljs-macros-path* ~path
               *cljs-macros-is-classpath* false]
       ~@body)))

(defn empty-env []
  {:ns (@namespaces *cljs-ns*) :context :statement :locals {}})

(defmacro ^:private debug-prn
  [& args]
  `(.println System/err (str ~@args)))

(defn warning [env s]
  (binding [*out* *err*]
    (println
     (str s (when (:line env)
       (str " at line " (:line env) " " *cljs-file*))))))

(defn confirm-var-exists [env prefix suffix]
  (when *cljs-warn-on-undeclared*
    (let [crnt-ns (-> env :ns :name)]
      (when (= prefix crnt-ns)
        (when-not (-> @namespaces crnt-ns :defs suffix)
          (warning env
            (str "WARNING: Use of undeclared Var " prefix "/" suffix)))))))

(defn resolve-ns-alias [env name]
  (let [sym (symbol name)]
    (get (:requires (:ns env)) sym sym)))

(defn core-name?
  "Is sym visible from core in the current compilation namespace?"
  [env sym]
  (and (get (:defs (@namespaces 'cljs.core)) sym)
       (not (contains? (-> env :ns :excludes) sym))))

(defn resolve-existing-var [env sym]
  (if (= (namespace sym) "js")
    {:name sym :ns 'js}
    (let [s (str sym)
          lb (-> env :locals sym)]
      (cond
       lb lb

       (namespace sym)
       (let [ns (namespace sym)
             ns (if (= "clojure.core" ns) "cljs.core" ns)
             full-ns (resolve-ns-alias env ns)]
         (confirm-var-exists env full-ns (symbol (name sym)))
         (merge (get-in @namespaces [full-ns :defs (symbol (name sym))])
           {:name (symbol (str full-ns) (str (name sym)))
            :ns full-ns}))

       (.contains s ".")
       (let [idx (.indexOf s ".")
             prefix (symbol (subs s 0 idx))
             suffix (subs s (inc idx))
             lb (-> env :locals prefix)]
         (if lb
           {:name (symbol (str (:name lb) suffix))}
           (do
             (confirm-var-exists env prefix (symbol suffix))
             (merge (get-in @namespaces [prefix :defs (symbol suffix)])
              {:name (if (= "" prefix) (symbol suffix) (symbol (str prefix) suffix))
               :ns prefix}))))

       (get-in @namespaces [(-> env :ns :name) :uses sym])
       (let [full-ns (get-in @namespaces [(-> env :ns :name) :uses sym])]
         (merge
          (get-in @namespaces [full-ns :defs sym])
          {:name (symbol (str full-ns) (str sym))
           :ns (-> env :ns :name)}))

       (get-in @namespaces [(-> env :ns :name) :imports sym])
       (recur env (get-in @namespaces [(-> env :ns :name) :imports sym]))

       :else
       (let [full-ns (if (core-name? env sym)
                       'cljs.core
                       (-> env :ns :name))]
         (confirm-var-exists env full-ns sym)
         (merge (get-in @namespaces [full-ns :defs sym])
           {:name (symbol (str full-ns) (str sym))
            :ns full-ns}))))))

(defn resolve-var [env sym]
  (if (= (namespace sym) "js")
    {:name sym}
    (let [s (str sym)
          lb (-> env :locals sym)]
      (cond
       lb lb

       (namespace sym)
       (let [ns (namespace sym)
             ns (if (= "clojure.core" ns) "cljs.core" ns)]
         {:name (symbol (str (resolve-ns-alias env ns)) (name sym))})

       (.contains s ".")
       (let [idx (.indexOf s ".")
             prefix (symbol (subs s 0 idx))
             suffix (subs s idx)
             lb (-> env :locals prefix)]
         (if lb
           {:name (symbol (str (:name lb) suffix))}
           {:name sym}))

       (get-in @namespaces [(-> env :ns :name) :uses sym])
       (let [full-ns (get-in @namespaces [(-> env :ns :name) :uses sym])]
         (merge
          (get-in @namespaces [full-ns :defs sym])
          {:name (symbol (str full-ns) (name sym))}))

       (get-in @namespaces [(-> env :ns :name) :imports sym])
       (recur env (get-in @namespaces [(-> env :ns :name) :imports sym]))

       :else
       (let [ns (if (core-name? env sym)
                  'cljs.core
                  (-> env :ns :name))]
         {:name (symbol (str ns) (name sym))})))))

(defn confirm-bindings [env names]
  (doseq [name names]
    (let [env (merge env {:ns (@namespaces *cljs-ns*)})
          ev (resolve-existing-var env name)]
      (when (and *cljs-warn-on-dynamic*
                 ev (not (-> ev :dynamic)))
        (warning env
          (str "WARNING: " (:name ev) " not declared ^:dynamic"))))))

(declare analyze analyze-symbol analyze-seq)

(def specials '#{if def fn* do let* loop* letfn* throw try* recur new set! ns deftype* defrecord* . js* & quote})

(def ^:dynamic *recur-frames* nil)
(def ^:dynamic *loop-lets* nil)

(defmacro disallowing-recur [& body]
  `(binding [*recur-frames* (cons nil *recur-frames*)] ~@body))

(defn analyze-keyword
    [env sym]
    {:op :constant :env env
     :form (if (= (namespace sym) (name *reader-ns-name*))
               (keyword (-> env :ns :name name) (name sym))
               sym)})

(defn analyze-block
  "returns {:statements .. :ret ..}"
  [env exprs]
  (let [statements (disallowing-recur
                     (seq (map #(analyze (assoc env :context :statement) %) (butlast exprs))))
        ret (if (<= (count exprs) 1)
              (analyze env (first exprs))
              (analyze (assoc env :context (if (= :statement (:context env)) :statement :return)) (last exprs)))]
    {:statements statements :ret ret}))

(defmulti parse (fn [op & rest] op))

(defmethod parse 'if
  [op env [_ test then else :as form] name]
  (let [test-expr (disallowing-recur (analyze (assoc env :context :expr) test))
        then-expr (analyze env then)
        else-expr (analyze env else)]
    {:env env :op :if :form form
     :test test-expr :then then-expr :else else-expr
     :unchecked @*unchecked-if*
     :children [test-expr then-expr else-expr]}))

(defmethod parse 'throw
  [op env [_ throw :as form] name]
  (let [throw-expr (disallowing-recur (analyze (assoc env :context :expr) throw))]
    {:env env :op :throw :form form
     :throw throw-expr
     :children [throw-expr]}))

(defn- block-children [{:keys [statements ret] :as block}]
  (when block (conj (vec statements) ret)))

(defmethod parse 'try*
  [op env [_ & body :as form] name]
  (let [body (vec body)
        catchenv (update-in env [:context] #(if (= :expr %) :return %))
        tail (peek body)
        fblock (when (and (seq? tail) (= 'finally (first tail)))
                  (rest tail))
        finally (when fblock
                  (analyze-block
                   (assoc env :context :statement)
                   fblock))
        body (if finally (pop body) body)
        tail (peek body)
        cblock (when (and (seq? tail)
                          (= 'catch (first tail)))
                 (rest tail))
        name (first cblock)
        locals (:locals catchenv)
        locals (if name
                 (assoc locals name {:name name})
                 locals)
        catch (when cblock
                (analyze-block (assoc catchenv :locals locals) (rest cblock)))
        body (if name (pop body) body)
        try (when body
              (analyze-block (if (or name finally) catchenv env) body))]
    (when name (assert (not (namespace name)) "Can't qualify symbol in catch"))
    {:env env :op :try* :form form
     :try try
     :finally finally
     :name name
     :catch catch
     :children (vec (mapcat block-children
                            [try catch finally]))}))

(defmethod parse 'def
  [op env form name]
  (let [pfn (fn
              ([_ sym] {:sym sym})
              ([_ sym init] {:sym sym :init init})
              ([_ sym doc init] {:sym sym :doc doc :init init}))
        args (apply pfn form)
        sym (:sym args)
        sym-meta (meta sym)
        tag (-> sym meta :tag)
        protocol (-> sym meta :protocol)
        dynamic (-> sym meta :dynamic)
        ns-name (-> env :ns :name)]
    (assert (not (namespace sym)) "Can't def ns-qualified name")
    (let [env (if (or (and (not= ns-name 'cljs.core)
                           (core-name? env sym))
                      (get-in @namespaces [ns-name :uses sym]))
                (let [ev (resolve-existing-var (dissoc env :locals) sym)]
                  (when *cljs-warn-on-redef*
                    (warning env
                      (str "WARNING: " sym " already refers to: " (symbol (str (:ns ev)) (str sym))
                           " being replaced by: " (symbol (str ns-name) (str sym)))))
                  (swap! namespaces update-in [ns-name :excludes] conj sym)
                  (update-in env [:ns :excludes] conj sym))
                env)
          name (:name (resolve-var (dissoc env :locals) sym))
          init-expr (when (contains? args :init)
                      (disallowing-recur
                       (analyze (assoc env :context :expr) (:init args) sym)))
          fn-var? (and init-expr (= (:op init-expr) :fn))
          export-as (when-let [export-val (-> sym meta :export)]
                      (if (= true export-val) name export-val))
          doc (or (:doc args) (-> sym meta :doc))]
      (when-let [v (get-in @namespaces [ns-name :defs sym])]
        (when (and *cljs-warn-on-fn-var*
                   (not (-> sym meta :declared))
                   (and (:fn-var v) (not fn-var?)))
          (warning env
            (str "WARNING: " (symbol (str ns-name) (str sym))
                 " no longer fn, references are stale"))))
      (swap! namespaces assoc-in [ns-name :defs sym]
                 (merge {:name name}
                   sym-meta
                   (when dynamic {:dynamic true})
                   (when-let [line (:line env)]
                     {:file *cljs-file* :line line})
                   ;; the protocol a protocol fn belongs to
                   (when protocol
                     {:protocol protocol})
                   ;; symbol for reified protocol
                   (when-let [protocol-symbol (-> sym meta :protocol-symbol)]
                     {:protocol-symbol protocol-symbol})
                   (when fn-var?
                     {:fn-var true
                      ;; protocol implementation context
                      :protocol-impl (:protocol-impl init-expr)
                      ;; inline protocol implementation context
                      :protocol-inline (:protocol-inline init-expr)
                      :variadic (:variadic init-expr)
                      :max-fixed-arity (:max-fixed-arity init-expr)
                      :method-params (map :params (:methods init-expr))})))
      (merge {:env env :op :def :form form
              :name name :doc doc :init init-expr}
             (when tag {:tag tag})
             (when dynamic {:dynamic true})
             (when export-as {:export export-as})
             (when init-expr {:children [init-expr]})))))

(defn- analyze-fn-method [env locals meth type]
  (let [param-names (first meth)
        variadic (boolean (some '#{&} param-names))
        param-names (vec (remove '#{&} param-names))
        body (next meth)
        [locals params] (reduce (fn [[locals params] name]
                                  (let [param {:name name
                                               :tag (-> name meta :tag)
                                               :shadow (locals name)}]
                                    [(assoc locals name param) (conj params param)]))
                                [locals []] param-names)
        fixed-arity (count (if variadic (butlast params) params))
        recur-frame {:params params :flag (atom nil)}
        block (binding [*recur-frames* (cons recur-frame *recur-frames*)]
                (analyze-block (assoc env :context :return :locals locals) body))]
    (merge {:env env :variadic variadic :params params :max-fixed-arity fixed-arity
            :type type :recurs @(:flag recur-frame)}
           block)))

(defmethod parse 'fn*
  [op env [_ & args :as form] name]
  (let [[name meths] (if (symbol? (first args))
                       [(first args) (next args)]
                       [name (seq args)])
        ;;turn (fn [] ...) into (fn ([]...))
        meths (if (vector? (first meths)) (list meths) meths)
        locals (:locals env)
        locals (if name (assoc locals name {:name name :shadow (locals name)}) locals)
        type (-> form meta ::type)
        fields (-> form meta ::fields)
        protocol-impl (-> form meta :protocol-impl)
        protocol-inline (-> form meta :protocol-inline)
        locals (reduce (fn [m fld]
                         (assoc m fld
                                {:name fld
                                 :field true
                                 :mutable (-> fld meta :mutable)
                                 :tag (-> fld meta :tag)
                                 :shadow (m fld)}))
                       locals fields)

        menv (if (> (count meths) 1) (assoc env :context :expr) env)
        menv (merge menv
               {:protocol-impl protocol-impl
                :protocol-inline protocol-inline})
        methods (map #(analyze-fn-method menv locals % type) meths)
        max-fixed-arity (apply max (map :max-fixed-arity methods))
        variadic (boolean (some :variadic methods))
        locals (if name
                 (update-in locals [name] assoc
                            :fn-var true
                            :variadic variadic
                            :max-fixed-arity max-fixed-arity
                            :method-params (map :params methods))
                 locals)
        methods (if name
                  ;; a second pass with knowledge of our function-ness/arity
                  ;; lets us optimize self calls
                  (map #(analyze-fn-method menv locals % type) meths)
                  methods)]
    ;;todo - validate unique arities, at most one variadic, variadic takes max required args
    {:env env :op :fn :form form :name name :methods methods :variadic variadic
     :recur-frames *recur-frames* :loop-lets *loop-lets*
     :jsdoc [(when variadic "@param {...*} var_args")]
     :max-fixed-arity max-fixed-arity
     :protocol-impl protocol-impl
     :protocol-inline protocol-inline
     :children (vec (mapcat block-children
                            methods))}))

(defmethod parse 'letfn*
  [op env [_ bindings & exprs :as form] name]
  (assert (and (vector? bindings) (even? (count bindings))) "bindings must be vector of even number of elements")
  (let [n->fexpr (into {} (map (juxt first second) (partition 2 bindings)))
        names    (keys n->fexpr)
        context  (:context env)
        [meth-env bes]
        (reduce (fn [[{:keys [locals] :as env} bes] n]
                  (let [be {:name   n
                            :tag    (-> n meta :tag)
                            :local  true
                            :shadow (locals n)}]
                    [(assoc-in env [:locals n] be)
                     (conj bes be)]))
                [env []] names)
        meth-env (assoc meth-env :context :expr)
        bes (vec (map (fn [{:keys [name shadow] :as be}]
                        (let [env (assoc-in meth-env [:locals name] shadow)]
                          (assoc be :init (analyze env (n->fexpr name)))))
                      bes))
        {:keys [statements ret]}
        (analyze-block (assoc meth-env :context (if (= :expr context) :return context)) exprs)]
    {:env env :op :letfn :bindings bes :statements statements :ret ret :form form
     :children (into (vec (map :init bes))
                     (conj (vec statements) ret))}))

(defmethod parse 'do
  [op env [_ & exprs :as form] _]
  (let [block (analyze-block env exprs)]
    (merge {:env env :op :do :form form :children (block-children block)} block)))

(defn analyze-let
  [encl-env [_ bindings & exprs :as form] is-loop]
  (assert (and (vector? bindings) (even? (count bindings))) "bindings must be vector of even number of elements")
  (let [context (:context encl-env)
        [bes env]
        (disallowing-recur
         (loop [bes []
                env (assoc encl-env :context :expr)
                bindings (seq (partition 2 bindings))]
           (if-let [[name init] (first bindings)]
             (do
               (assert (not (or (namespace name) (.contains (str name) "."))) (str "Invalid local name: " name))
               (let [init-expr (analyze env init)
                     be {:name name
                         :init init-expr
                         :tag (or (-> name meta :tag)
                                  (-> init-expr :tag)
                                  (-> init-expr :info :tag))
                         :local true
                         :shadow (-> env :locals name)}
                     be (if (= (:op init-expr) :fn)
                          (merge be
                            {:fn-var true
                             :variadic (:variadic init-expr)
                             :max-fixed-arity (:max-fixed-arity init-expr)
                             :method-params (map :params (:methods init-expr))})
                          be)]
                 (recur (conj bes be)
                        (assoc-in env [:locals name] be)
                        (next bindings))))
             [bes env])))
        recur-frame (when is-loop {:params bes :flag (atom nil)})
        {:keys [statements ret]}
        (binding [*recur-frames* (if recur-frame (cons recur-frame *recur-frames*) *recur-frames*)
                  *loop-lets* (cond
                               is-loop (or *loop-lets* ())
                               *loop-lets* (cons {:params bes} *loop-lets*))]
          (analyze-block (assoc env :context (if (= :expr context) :return context)) exprs))]
    {:env encl-env :op :let :loop is-loop
     :bindings bes :statements statements :ret ret :form form
     :children (into (vec (map :init bes))
                     (conj (vec statements) ret))}))

(defmethod parse 'let*
  [op encl-env form _]
  (analyze-let encl-env form false))

(defmethod parse 'loop*
  [op encl-env form _]
  (analyze-let encl-env form true))

(defmethod parse 'recur
  [op env [_ & exprs :as form] _]
  (let [context (:context env)
        frame (first *recur-frames*)
        exprs (disallowing-recur (vec (map #(analyze (assoc env :context :expr) %) exprs)))]
    (assert frame "Can't recur here")
    (assert (= (count exprs) (count (:params frame))) "recur argument count mismatch")
    (reset! (:flag frame) true)
    (assoc {:env env :op :recur :form form}
      :frame frame
      :exprs exprs
      :children exprs)))

(defmethod parse 'quote
  [_ env [_ x] _]
  {:op :constant :env env :form x})

(defmethod parse 'new
  [_ env [_ ctor & args :as form] _]
  (assert (symbol? ctor) "First arg to new must be a symbol")
  (disallowing-recur
   (let [enve (assoc env :context :expr)
         ctorexpr (analyze enve ctor)
         argexprs (vec (map #(analyze enve %) args))
         known-num-fields (:num-fields (resolve-existing-var env ctor))
         argc (count args)]
     (when (and known-num-fields (not= known-num-fields argc))
       (warning env
         (str "WARNING: Wrong number of args (" argc ") passed to " ctor)))

     {:env env :op :new :form form :ctor ctorexpr :args argexprs
      :children (into [ctorexpr] argexprs)})))

(defmethod parse 'set!
  [_ env [_ target val alt :as form] _]
  (let [[target val] (if alt
                       ;; (set! o -prop val)
                       [`(. ~target ~val) alt]
                       [target val])]
    (disallowing-recur
     (let [enve (assoc env :context :expr)
           targetexpr (cond
                       ;; TODO: proper resolve
                       (= target '*unchecked-if*)
                       (do
                         (reset! *unchecked-if* val)
                         ::set-unchecked-if)

                       (symbol? target)
                       (do
                         (let [local (-> env :locals target)]
                           (assert (or (nil? local)
                                       (and (:field local)
                                            (:mutable local)))
                                   "Can't set! local var or non-mutable field"))
                         (analyze-symbol enve target))

                       :else
                       (when (seq? target)
                         (let [targetexpr (analyze-seq enve target nil)]
                           (when (:field targetexpr)
                             targetexpr))))
           valexpr (analyze enve val)]
       (assert targetexpr "set! target must be a field or a symbol naming a var")
       (cond
        (= targetexpr ::set-unchecked-if) {:env env :op :no-op}
        :else {:env env :op :set! :form form :target targetexpr :val valexpr
               :children [targetexpr valexpr]})))))

(defn munge-path [ss]
  (clojure.lang.Compiler/munge (str ss)))

(defn ns->relpath [s]
  (str (string/replace (munge-path s) \. \/) ".cljs"))

(declare analyze-file)

(defn analyze-deps [deps]
  (doseq [dep deps]
    (when-not (:defs (@namespaces dep))
      (let [relpath (ns->relpath dep)]
        (when (io/resource relpath)
          (analyze-file relpath))))))

(defmethod parse 'ns
  [_ env [_ name & args :as form] _]
  (let [docstring (if (string? (first args)) (first args) nil)
        args      (if docstring (next args) args)
        excludes
        (reduce (fn [s [k exclude xs]]
                  (if (= k :refer-clojure)
                    (do
                      (assert (= exclude :exclude) "Only [:refer-clojure :exclude (names)] form supported")
                      (assert (not (seq s)) "Only one :refer-clojure form is allowed per namespace definition")
                      (into s xs))
                    s))
                #{} args)
        deps (atom #{})
        valid-forms (atom #{:use :use-macros :require :require-macros :import})
        error-msg (fn [spec msg] (str msg "; offending spec: " (pr-str spec)))
        parse-require-spec (fn parse-require-spec [macros? spec]
                             (assert (or (symbol? spec) (vector? spec))
                                     (error-msg spec "Only [lib.ns & options] and lib.ns specs supported in :require / :require-macros"))
                             (when (vector? spec)
                               (assert (symbol? (first spec))
                                       (error-msg spec "Library name must be specified as a symbol in :require / :require-macros"))
                               (assert (odd? (count spec))
                                       (error-msg spec "Only :as alias and :refer (names) options supported in :require"))
                               (assert (every? #{:as :refer} (map first (partition 2 (next spec))))
                                       (error-msg spec "Only :as and :refer options supported in :require / :require-macros"))
                               (assert (let [fs (frequencies (next spec))]
                                         (and (<= (fs :as 0) 1)
                                              (<= (fs :refer 0) 1)))
                                       (error-msg spec "Each of :as and :refer options may only be specified once in :require / :require-macros")))
                             (if (symbol? spec)
                               (recur macros? [spec])
                               (let [[lib & opts] spec
                                     {alias :as referred :refer :or {alias lib}} (apply hash-map opts)
                                     [rk uk] (if macros? [:require-macros :use-macros] [:require :use])]
                                 (assert (or (symbol? alias) (nil? alias))
                                         (error-msg spec ":as must be followed by a symbol in :require / :require-macros"))
                                 (assert (or (and (sequential? referred) (every? symbol? referred))
                                             (nil? referred))
                                         (error-msg spec ":refer must be followed by a sequence of symbols in :require / :require-macros"))
                                 (swap! deps conj lib)
                                 (merge (when alias {rk {alias lib}})
                                        (when referred {uk (apply hash-map (interleave referred (repeat lib)))})))))
        use->require (fn use->require [[lib kw referred :as spec]]
                       (assert (and (symbol? lib) (= :only kw) (sequential? referred) (every? symbol? referred))
                               (error-msg spec "Only [lib.ns :only (names)] specs supported in :use / :use-macros"))
                       [lib :refer referred])
        parse-import-spec (fn parse-import-spec [spec]
                            (assert (and (symbol? spec) (nil? (namespace spec)))
                                    (error-msg spec "Only lib.Ctor specs supported in :import"))
                            (swap! deps conj spec)
                            (let [ctor-sym (symbol (last (string/split (str spec) #"\.")))]
                              {:import  {ctor-sym spec}
                               :require {ctor-sym spec}}))
        spec-parsers {:require        (partial parse-require-spec false)
                      :require-macros (partial parse-require-spec true)
                      :use            (comp (partial parse-require-spec false) use->require)
                      :use-macros     (comp (partial parse-require-spec true) use->require)
                      :import         parse-import-spec}
        {uses :use requires :require uses-macros :use-macros requires-macros :require-macros imports :import :as params}
        (reduce (fn [m [k & libs]]
                  (assert (#{:use :use-macros :require :require-macros :import} k)
                          "Only :refer-clojure, :require, :require-macros, :use and :use-macros libspecs supported")
                  (assert (@valid-forms k)
                          (str "Only one " k " form is allowed per namespace definition"))
                  (swap! valid-forms disj k)
                  (apply merge-with merge m (map (spec-parsers k) libs)))
                {} (remove (fn [[r]] (= r :refer-clojure)) args))]
    (when (seq @deps)
      (analyze-deps @deps))
    (set! *cljs-ns* name)
    (load-core)
    (doseq [nsym (concat (vals requires-macros) (vals uses-macros))]
      (clojure.core/require nsym))
    (swap! namespaces #(-> %
                           (assoc-in [name :name] name)
                           (assoc-in [name :excludes] excludes)
                           (assoc-in [name :uses] uses)
                           (assoc-in [name :requires] requires)
                           (assoc-in [name :uses-macros] uses-macros)
                           (assoc-in [name :requires-macros]
                                     (into {} (map (fn [[alias nsym]]
                                                     [alias (find-ns nsym)])
                                                   requires-macros)))
                           (assoc-in [name :imports] imports)))
    {:env env :op :ns :form form :name name :uses uses :requires requires :imports imports
     :uses-macros uses-macros :requires-macros requires-macros :excludes excludes}))

(defmethod parse 'deftype*
  [_ env [_ tsym fields pmasks :as form] _]
  (let [t (:name (resolve-var (dissoc env :locals) tsym))]
    (swap! namespaces update-in [(-> env :ns :name) :defs tsym]
           (fn [m]
             (let [m (assoc (or m {})
                       :name t
                       :type true
                       :num-fields (count fields))]
               (merge m
                 {:protocols (-> tsym meta :protocols)}
                 (when-let [line (:line env)]
                   {:file *cljs-file*
                    :line line})))))
    {:env env :op :deftype* :form form :t t :fields fields :pmasks pmasks}))

(defmethod parse 'defrecord*
  [_ env [_ tsym fields pmasks :as form] _]
  (let [t (:name (resolve-var (dissoc env :locals) tsym))]
    (swap! namespaces update-in [(-> env :ns :name) :defs tsym]
           (fn [m]
             (let [m (assoc (or m {}) :name t :type true)]
               (merge m
                 {:protocols (-> tsym meta :protocols)}
                 (when-let [line (:line env)]
                   {:file *cljs-file*
                    :line line})))))
    {:env env :op :defrecord* :form form :t t :fields fields :pmasks pmasks}))

;; dot accessor code

(def ^:private property-symbol? #(boolean (and (symbol? %) (re-matches #"^-.*" (name %)))))

(defn- classify-dot-form
  [[target member args]]
  [(cond (nil? target) ::error
         :default      ::expr)
   (cond (property-symbol? member) ::property
         (symbol? member)          ::symbol
         (seq? member)             ::list
         :default                  ::error)
   (cond (nil? args) ()
         :default    ::expr)])

(defmulti build-dot-form #(classify-dot-form %))

;; (. o -p)
;; (. (...) -p)
(defmethod build-dot-form [::expr ::property ()]
  [[target prop _]]
  {:dot-action ::access :target target :field (-> prop name (.substring 1) symbol)})

;; (. o -p <args>)
(defmethod build-dot-form [::expr ::property ::list]
  [[target prop args]]
  (throw (Error. (str "Cannot provide arguments " args " on property access " prop))))

(defn- build-method-call
  "Builds the intermediate method call map used to reason about the parsed form during
  compilation."
  [target meth args]
  (if (symbol? meth)
    {:dot-action ::call :target target :method meth :args args}
    {:dot-action ::call :target target :method (first meth) :args args}))

;; (. o m 1 2)
(defmethod build-dot-form [::expr ::symbol ::expr]
  [[target meth args]]
  (build-method-call target meth args))

;; (. o m)
(defmethod build-dot-form [::expr ::symbol ()]
  [[target meth args]]
  (build-method-call target meth args))

;; (. o (m))
;; (. o (m 1 2))
(defmethod build-dot-form [::expr ::list ()]
  [[target meth-expr _]]
  (build-method-call target (first meth-expr) (rest meth-expr)))

(defmethod build-dot-form :default
  [dot-form]
  (throw (Error. (str "Unknown dot form of " (list* '. dot-form) " with classification " (classify-dot-form dot-form)))))

(defmethod parse '.
  [_ env [_ target & [field & member+] :as form] _]
  (disallowing-recur
   (let [{:keys [dot-action target method field args]} (build-dot-form [target field member+])
         enve        (assoc env :context :expr)
         targetexpr  (analyze enve target)]
     (case dot-action
           ::access {:env env :op :dot :form form
                     :target targetexpr
                     :field field
                     :children [targetexpr]
                     :tag (-> form meta :tag)}
           ::call   (let [argexprs (map #(analyze enve %) args)]
                      {:env env :op :dot :form form
                       :target targetexpr
                       :method method
                       :args argexprs
                       :children (into [targetexpr] argexprs)
                       :tag (-> form meta :tag)})))))

(defmethod parse 'js*
  [op env [_ jsform & args :as form] _]
  (assert (string? jsform))
  (if args
    (disallowing-recur
     (let [seg (fn seg [^String s]
                 (let [idx (.indexOf s "~{")]
                   (if (= -1 idx)
                     (list s)
                     (let [end (.indexOf s "}" idx)]
                       (cons (subs s 0 idx) (seg (subs s (inc end))))))))
           enve (assoc env :context :expr)
           argexprs (vec (map #(analyze enve %) args))]
       {:env env :op :js :segs (seg jsform) :args argexprs
        :tag (-> form meta :tag) :form form :children argexprs}))
    (let [interp (fn interp [^String s]
                   (let [idx (.indexOf s "~{")]
                     (if (= -1 idx)
                       (list s)
                       (let [end (.indexOf s "}" idx)
                             inner (:name (resolve-existing-var env (symbol (subs s (+ 2 idx) end))))]
                         (cons (subs s 0 idx) (cons inner (interp (subs s (inc end)))))))))]
      {:env env :op :js :form form :code (apply str (interp jsform))
       :tag (-> form meta :tag)})))

(defn parse-invoke
  [env [f & args :as form]]
  (disallowing-recur
   (let [enve (assoc env :context :expr)
         fexpr (analyze enve f)
         argexprs (vec (map #(analyze enve %) args))
         argc (count args)]
     (if (and *cljs-warn-fn-arity* (-> fexpr :info :fn-var))
       (let [{:keys [variadic max-fixed-arity method-params name]} (:info fexpr)]
         (when (and (not (some #{argc} (map count method-params)))
                    (or (not variadic)
                        (and variadic (< argc max-fixed-arity))))
           (warning env
             (str "WARNING: Wrong number of args (" argc ") passed to " name)))))
     (if (and *cljs-warn-fn-deprecated* (-> fexpr :info :deprecated)
              (not (-> form meta :deprecation-nowarn)))
       (warning env
         (str "WARNING: " (-> fexpr :info :name) " is deprecated.")))
     {:env env :op :invoke :form form :f fexpr :args argexprs
      :tag (or (-> fexpr :info :tag) (-> form meta :tag)) :children (into [fexpr] argexprs)})))

(defn analyze-symbol
  "Finds the var associated with sym"
  [env sym]
  (let [ret {:env env :form sym}
        lb (-> env :locals sym)]
    (if lb
      (assoc ret :op :var :info lb)
      (assoc ret :op :var :info (resolve-existing-var env sym)))))

(defn get-expander [sym env]
  (let [mvar
        (when-not (or (-> env :locals sym)        ;locals hide macros
                      (and (or (-> env :ns :excludes sym)
                               (get-in @namespaces [(-> env :ns :name) :excludes sym]))
                           (not (or (-> env :ns :uses-macros sym)
                                    (get-in @namespaces [(-> env :ns :name) :uses-macros sym])))))
          (if-let [nstr (namespace sym)]
            (when-let [ns (cond
                           (= "clojure.core" nstr) (find-ns 'cljs.core)
                           (.contains nstr ".") (find-ns (symbol nstr))
                           :else
                           (-> env :ns :requires-macros (get (symbol nstr))))]
              (.findInternedVar ^clojure.lang.Namespace ns (symbol (name sym))))
            (if-let [nsym (-> env :ns :uses-macros sym)]
              (.findInternedVar ^clojure.lang.Namespace (find-ns nsym) sym)
              (.findInternedVar ^clojure.lang.Namespace (find-ns 'cljs.core) sym))))]
    (when (and mvar (.isMacro ^clojure.lang.Var mvar))
      @mvar)))

(defn macroexpand-1 [env form]
  (let [op (first form)]
    (if (specials op)
      form
      (if-let [mac (and (symbol? op) (get-expander op env))]
        (binding [*ns* (create-ns *cljs-ns*)]
          (apply mac form env (rest form)))
        (if (symbol? op)
          (let [opname (str op)]
            (cond
             (= (first opname) \.) (let [[target & args] (next form)]
                                     (with-meta (list* '. target (symbol (subs opname 1)) args)
                                       (meta form)))
             (= (last opname) \.) (with-meta
                                    (list* 'new (symbol (subs opname 0 (dec (count opname)))) (next form))
                                    (meta form))
             :else form))
          form)))))

(defn analyze-seq
  [env form name]
  (let [env (assoc env :line
                   (or (-> form meta :line)
                       (:line env)))]
    (let [op (first form)]
      (assert (not (nil? op)) "Can't call nil")
      (let [mform (macroexpand-1 env form)]
        (if (identical? form mform)
          (if (specials op)
            (parse op env form name)
            (parse-invoke env form))
          (analyze env mform name))))))

(declare analyze-wrap-meta)

(defn analyze-map
  [env form name]
  (let [expr-env (assoc env :context :expr)
        simple-keys? (every? #(or (string? %) (keyword? %))
                             (keys form))
        ks (disallowing-recur (vec (map #(analyze expr-env % name) (keys form))))
        vs (disallowing-recur (vec (map #(analyze expr-env % name) (vals form))))]
    (analyze-wrap-meta {:op :map :env env :form form
                        :keys ks :vals vs :simple-keys? simple-keys?
                        :children (vec (interleave ks vs))}
                       name)))

(defn analyze-vector
  [env form name]
  (let [expr-env (assoc env :context :expr)
        items (disallowing-recur (vec (map #(analyze expr-env % name) form)))]
    (analyze-wrap-meta {:op :vector :env env :form form :items items :children items} name)))

(defn analyze-set
  [env form name]
  (let [expr-env (assoc env :context :expr)
        items (disallowing-recur (vec (map #(analyze expr-env % name) form)))]
    (analyze-wrap-meta {:op :set :env env :form form :items items :children items} name)))

(defn analyze-wrap-meta [expr name]
  (let [form (:form expr)]
    (if (meta form)
      (let [env (:env expr) ; take on expr's context ourselves
            expr (assoc-in expr [:env :context] :expr) ; change expr to :expr
            meta-expr (analyze-map (:env expr) (meta form) name)]
        {:op :meta :env env :form form
         :meta meta-expr :expr expr :children [meta-expr expr]})
      expr)))

(defn analyze
  "Given an environment, a map containing {:locals (mapping of names to bindings), :context
  (one of :statement, :expr, :return), :ns (a symbol naming the
  compilation ns)}, and form, returns an expression object (a map
  containing at least :form, :op and :env keys). If expr has any (immediately)
  nested exprs, must have :children [exprs...] entry. This will
  facilitate code walking without knowing the details of the op set."
  ([env form] (analyze env form nil))
  ([env form name]
     (let [form (if (instance? clojure.lang.LazySeq form)
                  (or (seq form) ())
                  form)]
       (load-core)
       (cond
        (symbol? form) (analyze-symbol env form)
        (and (seq? form) (seq form)) (analyze-seq env form name)
        (map? form) (analyze-map env form name)
        (vector? form) (analyze-vector env form name)
        (set? form) (analyze-set env form name)
        (keyword? form) (analyze-keyword env form)
        :else {:op :constant :env env :form form}))))

(defn analyze-file
  [^String f]
  (let [res (if (re-find #"^file://" f) (java.net.URL. f) (io/resource f))]
    (assert res (str "Can't find " f " in classpath"))
    (binding [*cljs-ns* 'cljs.user
              *cljs-file* (.getPath ^java.net.URL res)
              *ns* *reader-ns*]
      (with-open [r (io/reader res)]
        (let [env (empty-env)
              pbr (clojure.lang.LineNumberingPushbackReader. r)
              eof (Object.)]
          (loop [r (read pbr false eof false)]
            (let [env (assoc env :ns (get-namespace *cljs-ns*))]
              (when-not (identical? eof r)
                (analyze env r)
                (recur (read pbr false eof false))))))))))