reader.cljd

(ns cljd.reader
  (:require ["dart:io" :as io]
            ["dart:async" :as async]))

(deftype ReaderInput [^#/(async/Stream String) in
                      ^:mutable ^#/(async/StreamSubscription? String) subscription
                      ^:mutable ^#/(async/Completer? String?) completer
                      ^:mutable ^String? buffer]
  (^void init_stream_subscription [this]
   (set! subscription
     (doto (.listen in
             (fn [^String s]
               (assert (nil? buffer))
               (when-not (== "" s)
                 (.complete (.-completer this) s)
                 (.pause (.-subscription this))))
             .onDone
             (fn []
               (assert (nil? buffer))
               (.complete (.-completer this) nil)
               (set! (.-subscription this) nil)
               nil))
       (.pause)))
   nil)
  (^#/(async/FutureOr String?) read [this]
   (when-not (nil? subscription)
     (if-some [buf buffer]
       (do (set! buffer nil)
           (.value #/(async/Future String?) buf))
       (do (set! completer (async/Completer.))
           (.resume subscription)
           (.-future completer)))))
  (^void unread [this ^String s]
   (assert (nil? buffer))
   (assert (not (nil? subscription)))
   (set! buffer (when-not (== "" s) s))
   nil)
  #_(^#/(Future void) ^:async close [this]
   (when-some [sub subscription]
     (await (.cancel sub))
     (set! subscription nil)
     nil)))

(defn ^ReaderInput make-reader-input [^#/(async/StreamController String) controller]
  (doto (ReaderInput. (.-stream controller) nil nil nil) (.init_stream_subscription)))

(defn- saget
  {:inline (fn [s idx] (list '. `^String ~s "[]" `^int ~idx))
   :inline-arities #{2}}
  ([^String s ^int idx]
   (. s "[]" idx))
  ([^String s ^int idx & idxs]
   (apply saget (saget s idx) idxs)))

;; read-* functions
(declare ^:async ^:dart read)

(defn ^int cu0 [^String ch] (.codeUnitAt ch 0))

(defn ^#/(Future cljd.core/PersistentList) ^:async read-list [^ReaderInput rdr]
  (let [result #dart[]]
    (loop []
      (let [val (await (read rdr (cu0 ")")))]
        (if (== val rdr)
          (-list-lit result)
          (do (.add result val)
              (recur)))))))

(defn ^#/(Future cljd.core/PersistentHashMap) ^:async read-hash-map [^ReaderInput rdr]
  (let [result #dart[]]
    (loop []
      (let [val (await (read rdr (cu0 "}")))]
        (if (== val rdr)
          (if (zero? (bit-and 1 (.-length result)))
            (-map-lit result)
            (throw (FormatException. "Map literal must contain an even number of forms")))
          (do (.add result val)
              (recur)))))))

(defn ^#/(Future cljd.core/PersistentHashSet) ^:async read-hash-set [^ReaderInput rdr]
  (let [result #dart[]]
    (loop []
      (let [val (await (read rdr (cu0 "}")))]
        (if (== val rdr)
          (set result)
          (do (.add result val)
              (recur)))))))

(defn ^#/(Future cljd.core/PersistentVector) ^:async read-vector [^ReaderInput rdr]
  (let [result #dart[]]
    (loop []
      (let [val (await (read rdr (cu0 "]")))]
        (if (== val rdr)
          (if (< 32 (.-length result))
            (vec result)
            (-vec-owning result))
          (do (.add result val)
              (recur)))))))

(def ^RegExp COMMENT-CONTENT-REGEXP #"[^\r\n]*")

(defn ^:async read-comment [^ReaderInput rdr]
  (loop []
    (if-some [s (await (.read rdr))]
      (let [index (or (some-> (.matchAsPrefix COMMENT-CONTENT-REGEXP s) .-end) 0)]
        (if (< index (.-length s))
          (doto rdr (.unread (.substring s index)))
          (recur)))
      rdr)))

(defn ^:async read-regexp [^ReaderInput rdr]
  (let [sb (StringBuffer.)
        string (await (.read rdr))]
    (loop [index 0]
      (let [ch (saget string index)]
        (if (== "\"" ch)
          (do (.unread rdr (.substring string (inc index)))
              (RegExp. (.toString sb)))
          (if (< (cu0 ch) 0)
            (throw (FormatException. "EOF while reading regex"))
            (do (.write sb ch)
                (if (== "\\" ch)
                  (let [index (inc index)
                        ch (saget string index)]
                    (if (< (cu0 ch) 0)
                      (throw (FormatException. "EOF while reading regex"))
                      (do (.write sb ch)
                          (recur (inc index)))))
                  (recur (inc index))))))))))

(defn ^:async read-meta [^ReaderInput rdr]
  (let [meta (await (read rdr -1))
        meta (if (or (symbol? meta) (string? meta))
               {:tag meta}
               (if (keyword? meta)
                 {meta true}
                 (if (map? meta)
                   meta
                   (throw (FormatException. "Metadata must be Symbol,Keyword,String or Map")))))
        obj (await (read rdr -1))]
    (if (satisfies? cljd.core/IWithMeta obj)
      (with-meta obj meta)
      ;;TODO handle IReference with reset-meta
      (throw (FormatException. "Metadata can only be applied to IWithMeta")))))

(def ^RegExp STRING-CONTENT-REGEXP (RegExp. "(?:[^\"\\\\]|\\\\.)*"))
(def ^RegExp STRING-ESC-REGEXP (RegExp. "\\\\(?:u([0-9a-fA-F]{0,4})|([0-7]{1,3})|(.))"))

(defn ^:async read-string-content [^ReaderInput rdr]
  (let [f ^:async (fn ^String [^ReaderInput rdr]
                    (let [sb (StringBuffer.)]
                      (loop []
                        (if-some [^String string (await (.read rdr))]
                          (let [^int i (or (some-> (.matchAsPrefix STRING-CONTENT-REGEXP string) .-end) 0)]
                            (.write sb (.substring string 0 i))
                            (if (< i (.-length string))
                              (do (.unread rdr (.substring string (inc i)))
                                  (.toString sb))
                              (recur)))
                          (throw (FormatException. "Unexpected EOF while reading a string."))))))]
    (.replaceAllMapped (await (f rdr))
      STRING-ESC-REGEXP
      (fn [^Match m]
        (if-some [^String m1 (.group m 1)]
          (if (< (.-length m1) 4)
            (throw (FormatException. (str "Unsupported escape for character: \\u" m1 " \\u MUST be followed by 4 hexadecimal digits")))
            (String/fromCharCode (int/parse m1 .radix 16)))
          (if-some [^String m2 (.group m 2)]
            (String/fromCharCode (int/parse m2 .radix 8))
            (let [m3 (.group m 3)]
              (case m3
                "\"" (str m3)
                "\\" (str m3)
                "b" "\b"
                "n" "\n"
                "r" "\r"
                "t" "\t"
                "f" "\f"
                (throw (FormatException. (str "Unsupported escape character: \\" m3)))))))))))

(def ^:dynamic *arg-env* nil)

(declare ^:dart interpret-token ^:dart ^:async read-token ^:dart terminating?)

(defn ^:async read-arg [^ReaderInput rdr]
  ;; funny case `(let [% 1] %)` > 1
  (if (nil? *arg-env*)
    (interpret-token (await (read-token rdr "%")))
    (let [string (await (.read rdr))
          ch (cu0 (saget string 0))]
      (if (or (< ch 0) (terminating? ch))
        (let [sym (symbol "param")]
          (.unread rdr (.substring string 1))
          (set! *arg-env* (assoc *arg-env* 1 sym))
          sym)
        (if-some [^Match m (.matchAsPrefix #"(?:([\d]+)|(&))([^\d&]).*$" string)]
          (if-some [^String g3 (.group m 3)]
            (if (terminating? (cu0 g3))
              (let [g1 (.group m 1)
                    g2 (.group m 2)]
                (cond
                  g1 (let [sym (symbol (str "param" g1))]
                       (.unread rdr (.substring string (.-length g1)))
                       (set! *arg-env* (assoc *arg-env* (int/parse g1) sym))
                       sym)
                  g2 (do (.unread rdr (.substring string 1))
                         (set! *arg-env* (assoc *arg-env* -1 'parammore))
                         'parammore)))
              (throw (FormatException. "arg literal must be %, %& or %integer"))))
          (throw (FormatException. "arg literal must be %, %& or %integer")))))))

(defn ^:async read-fn [^ReaderInput rdr]
  (when-not (nil? *arg-env*)
    (throw (FormatException. "Nested #()s are not allowed")))
  (binding [*arg-env* {}]
    (let [result (await (read-list rdr))
          arg-count (cond-> (->> (keys *arg-env*) (apply max 0))
                      (*arg-env* -1) (+ 2))]
      (list 'fn*
        (list (reduce #(let [[n param] %2]
                         (if (< n 0)
                           (-> (assoc %1 (dec arg-count) param)
                             (assoc (- arg-count 2) '&))
                           (assoc %1 (dec n) param)))
                (vec (repeat arg-count '_)) *arg-env*)
          result)))))

(defn ^:async read-unquote [^ReaderInput rdr]
  (let [string (await (.read rdr))
        char (saget string 0)]
    (if (< (cu0 char) 0)
      (throw (FormatException. "EOF while reading character"))
      (if (== char "@")
        (do (.unread rdr (.substring string 1))
            (list 'cljd.core/unquote-splicing (await (read rdr -1))))
        (do (.unread rdr string)
            (list 'cljd.core/unquote (await (read rdr -1))))))))

(declare ^:dart sq-expand-list)

(defprotocol IResolver
  (currentNS [resolver])
  (resolveClass [resolver sym])
  (resolveAlias [resolver sym])
  (resolveVar [resolver sym]))

(def ^:dynamic *resolver* nil)
(def ^:dynamic *gensym-env* nil)

(defn unquote? [form]
  (and (seq? form) (= 'cljd.core/unquote (first form))))

(defn unquote-splicing? [form]
  (and (seq? form) (= 'cljd.core/unquote-splicing (first form))))

;; TODO: should not be in reader.cljd
(defn special-form? [form]
  (contains? '#{. set! dart/is? dart/await dart/assert throw new ns try case* quote do var let* loop* recur
                if fn* letfn def reify* deftype* defprotocol* extend-type-protocol*} form))

(defn- syntax-quote [form]
  (cond
    (special-form? form) (list 'quote form)
    (symbol? form)
    (let [nsform (namespace form)
          nameform (name form)]
      (->> (cond
             (and (nil? nsform) (.endsWith nameform "#"))
             (if  (nil? *gensym-env*)
               ;; Should never happen
               (throw (FormatException. "Gensym literal not in syntax-quote"))
               (or
                 (*gensym-env* form)
                 (let [gs (symbol nil
                            (str (gensym (str (.substring nameform 0 (dec (.-length nameform))) "__")) "__auto__"))]
                   (set! *gensym-env* (assoc *gensym-env* form gs))
                   gs)))
             (and (nil? nsform) (.endsWith nameform "."))
             (let [rc (resolveClass *resolver* (symbol nil (.substring nameform 0 (dec (.-length nameform)))))]
               (symbol (namespace rc) (str (name rc) ".")))
             (and (nil? nsform) (== (saget nameform 0) "."))
             form
             :else
             (let [nsym (let [alias (some->> nsform (symbol nil))
                              nsym (some->> alias (resolveClass *resolver*))]
                          (if (nil? nsym) (resolveAlias *resolver* alias) nsym))]
               (if (not (nil? nsym))
                 (symbol (name nsym) nameform)
                 (if (nil? nsform)
                   (let [rsym (resolveClass *resolver* form)
                         rsym (if (nil? rsym) (resolveVar *resolver* form) rsym)]
                     (if (not (nil? rsym))
                       rsym
                       (symbol (name (currentNS *resolver*)) nameform)))
                   form))))
        (list 'quote)))
    (unquote? form) (second form)
    (unquote-splicing? form) (throw (FormatException. "splice not in list"))
    (number? form) form
    (string? form) form
    (keyword? form) form
    (coll? form)
    (cond
      ;; TODO records
      (vector? form)
      (list 'cljd.core/apply 'cljd.core/vector (list 'cljd.core/seq (cons 'cljd.core/concat (sq-expand-list form))))
      (set? form)
      (list 'cljd.core/apply 'cljd.core/hash-set (list 'cljd.core/seq (cons 'cljd.core/concat (sq-expand-list form))))
      (map? form)
      (list 'cljd.core/apply 'cljd.core/hash-map (list 'cljd.core/seq (cons 'cljd.core/concat (sq-expand-list (apply concat form)))))
      (or (list? form) (seq? form))
      (list 'cljd.core/seq (cons 'cljd.core/concat (sq-expand-list form)))
      :else (throw (FormatException. "Unknown Collection type")))
    :else (list 'quote form)))

(defn- sq-expand-list [s]
  (doall (map #(cond
                 (unquote? %) (list 'cljd.core/list (second %))
                 (unquote-splicing? %) (second %)
                 :else (list 'cljd.core/list (syntax-quote %))) s)))

(defn ^:async read-syntax-quote [^ReaderInput rdr]
  (binding [*gensym-env* {}]
    (syntax-quote (await (read rdr -1)))))

(defn ^:async read-namespace-map [^ReaderInput rdr]
  (let [string (await (.read rdr))
        auto (== ":" (saget string 0))
        key (if (== -1 (.indexOf (if auto (.substring string 1) string) #"^[\s,{]"))
              (await (read (doto rdr (.unread (str ":" string))) -1))
              (if auto
                (do
                  (.unread rdr (.substring string 1))
                  (currentNS *resolver*))
                (throw (FormatException. "Namespaced map must specify a namespace")))) ]
    (when-not (nil? (namespace key))
      (throw (FormatException. (str "Namespaced map must specify a valid namespace: " (namespace key) "/" (name key)))))
    (let [m (await (read rdr -1))]
      (when-not (map? m)
        (throw (FormatException. "Namespaced map must specify a map")))
      (into {} (for [[k v] m
                     :let [k' (cond
                                (keyword? k)
                                (cond-> k
                                  (== "_" (namespace k)) (->> name (keyword nil))
                                  (nil? (namespace k)) (->> name (keyword (name key))))
                                (symbol? k)
                                (cond-> k
                                  (== "_" (namespace k)) (->> name (symbol nil))
                                  (nil? (namespace k)) (->> name (symbol (name key))))
                                :else k)]]
                 [k' v])))))

(def ^:dynamic *top-level-form* nil)
(def ^:dynamic *features* #{:cljd :clj})

(defn ^:async read-conditional
  [^ReaderInput rdr]
  ;; TODO : manage EOF
  ;; TODO: should check if reader conditional are allowed
  ;; TODO: handle preserve read-cond
  (let [string (await (.read rdr))
        splicing (if (== "@" (saget string 0))
                   (do (.unread rdr (.substring string 1)) true)
                   (do (.unread rdr string) false))
        [_ expr :as body] (await (read rdr -1))
        ;; TODO : in clj java.util.List but in Dart, PV are List and PL are also List...
        is-list? (list? body)]
    (when-not is-list?
      (throw (FormatException. "read-cond body must be a list")))
    (when-not (or (dart/is? expr List) (not splicing))
      (throw (FormatException. "Spliced form list in read-cond-splicing must implement dart:core/List")))
    (when-not (or (not splicing) (not *top-level-form*))
      (throw (FormatException. "Reader conditional splicing not allowed at the top level.")))
    (let [discard1 ^:unique (Object.)
          discard ^:unique (Object.)
          hold ^:unique (Object.)
          check-feature (fn [feature]
                          (when-not (keyword? feature)
                            (throw (FormatException. (str "Feature should be a keyword: " feature))))
                          (when (#{:none :else} feature)
                            (throw (FormatException. (str "Feature name " feature " is reserved."))))
                          (if (contains? *features* feature)
                            hold
                            discard1))
          result
          (reduce (fn [state form]
                    (cond
                      (identical? hold state) (reduced form)
                      (identical? discard1 state) discard
                      (identical? discard state) (check-feature form)))
            discard body)]
      (when (identical? result hold)
        (throw (FormatException. "read-cond requires an even number of forms.")))
      (when (or (identical? result discard1) (identical? result discard))
        (throw (FormatException. "EOF while reading")))
      (if splicing
        (let [post (await (.read rdr))]
          (doto rdr (.unread (str (apply pr-str result) post))))
        result))))

(defn read-tagged [^ReaderInput rdr ^cljd.core/Symbol tag form]
  (if-some [dr-fn (or (some-> cljd.core/*data-readers* tag) (some-> cljd.core/default-data-readers tag))]
    (dr-fn form)
    (if-some [default-fn (some-> cljd.core/*default-data-reader-fn* tag)]
      (default-fn tag form)
      (throw (FormatException. (str "No reader function for tag " tag))))))

(defn ^:async read-record [^ReaderInput rdr]
  (throw (Exception. "read-reacord NOT IMPLEMENTED YET")))

(defn ^:async ctor-reader [^ReaderInput rdr]
  (let [tag (await (read rdr -1))]
    (when-not (symbol? tag)
      (throw (FormatException. "Reader tag must be a symbol")))
    (let [form (await (read rdr -1))]
      ;; TODO: handle preserve read-cond
      (if (.contains (name tag) ".")
        (read-record rdr)
        (read-tagged rdr tag form)))))

(def dispatch-macros
  {"_"  ^:async (fn [^ReaderInput rdr] (await (read rdr -1)) rdr)
   "^"  ^:async (fn [^ReaderInput rdr] (await (read-meta rdr)))
   "{"  ^:async (fn [^ReaderInput rdr] (await (read-hash-set rdr)))
   "("  ^:async (fn [^ReaderInput rdr] (await (read-fn rdr)))
   "!"  ^:async (fn [^ReaderInput rdr] (await (read-comment rdr)))
   "\"" ^:async (fn [^ReaderInput rdr] (await (read-regexp rdr)))
   "'"  ^:async (fn [^ReaderInput rdr] (list 'var (await (read rdr -1))))
   "<"  ^:async (fn [^ReaderInput rdr] (throw (FormatException. "Unreadable form")))
   ":"  ^:async (fn [^ReaderInput rdr] (await (read-namespace-map rdr)))
   "?"  ^:async (fn [^ReaderInput rdr] (await (read-conditional rdr)))})

(def macros
  {"("  ^:async (fn [^ReaderInput rdr] (await (read-list rdr)))
   ")"  ^:async (fn [_] (throw (FormatException. "EOF while reading, starting at line")))
   "{"  ^:async (fn [^ReaderInput rdr] (await (read-hash-map rdr)))
   "}"  ^:async (fn [_] (throw (FormatException. "EOF while reading, starting at line")))
   "["  ^:async (fn [^ReaderInput rdr] (await (read-vector rdr)))
   "]"  ^:async (fn [_] (throw (FormatException. "EOF while reading, starting at line")))
   "'"  ^:async (fn [^ReaderInput rdr] (list (symbol nil "quote") (await (read rdr -1))))
   "`"  ^:async (fn [^ReaderInput rdr] (await (read-syntax-quote rdr)))
   "@"  ^:async (fn [^ReaderInput rdr] (list 'cljd.core/deref (await (read rdr -1))))
   ";"  ^:async (fn [^ReaderInput rdr] (await (read-comment rdr)))
   "^"  ^:async (fn [^ReaderInput rdr] (await (read-meta rdr)))
   "\"" ^:async (fn [^ReaderInput rdr] (await (read-string-content rdr)))
   "%"  ^:async (fn [^ReaderInput rdr] (await (read-arg rdr)))
   "~"  ^:async (fn [^ReaderInput rdr] (await (read-unquote rdr)))
   "#"  ^:async (fn [^ReaderInput rdr]
                  (if-some [string (await (.read rdr))]
                    (if-some [macroreader (dispatch-macros (saget string 0))]
                      (do (.unread rdr (.substring string 1))
                          (await (macroreader rdr)))
                      (if-some [result (do (.unread rdr string)
                                           (await (ctor-reader rdr)))]
                        result
                        (throw (FormatException. (str "Unepxected dispatch sequence: #" (saget string 0))))))
                    (throw (FormatException. "EOF while reading dispatch sequence.")))) })

(def ^RegExp SPACE-REGEXP #"[\s,]*")

(defn ^bool terminating? [^int code-unit]
  (let [ch (String/fromCharCode code-unit)]
    (cond
      (< -1 (.indexOf "'#%" ch)) false
      (macros ch) true
      (< 0 (or (some-> (.matchAsPrefix SPACE-REGEXP ch) .-end) 0)) true
      :else false)))

(defn ^#/(Future String) ^:async read-token [^ReaderInput rdr ^String init]
  (let [sb (StringBuffer. init)]
    (loop [^int index 0
           ^String string ""]
      (if (== index (.-length string))
        (do (.write sb string)
            (when-some [s (await (.read rdr))]
              (recur 0 ^String s)))
        (let [cu (.codeUnitAt string index)]
          (if (terminating? cu)
            (do (.write sb (.substring string 0 index))
                (.unread rdr (.substring string index)))
            (recur (inc index) string)))))
    (.toString sb)))


(def ^RegExp INT-REGEXP (RegExp. "([-+]?)(?:(0)|([1-9][0-9]*)|0[xX]([0-9A-Fa-f]+)|0([0-7]+)|([1-9][0-9]?)[rR]([0-9A-Za-z]+)|0[0-9]+)(N)?$"))
(def ^RegExp DOUBLE-REGEXP (RegExp. "([-+]?[0-9]+([.][0-9]*)?([eE][-+]?[0-9]+)?)(M)?$"))
(def ^RegExp SYMBOL-REGEXP (RegExp. "(?:([:]{2})|([:]))?(?:([^0-9/:].*)/)?(/|[^0-9/][^/]*)$"))

(defn interpret-token [^String token]
  (case token
    "nil" nil
    "true" true
    "false" false
    (if-some [m (.matchAsPrefix INT-REGEXP token)]
      (let [parse (if ^some (.group m 8)
                    (if (== "-" (.group m 1))
                      (fn ^BigInt [^String s ^int radix] (- (BigInt/parse s .radix radix)))
                      (fn ^BigInt [^String s ^int radix] (BigInt/parse s .radix radix)))
                    (if (== "-" (.group m 1))
                      (fn ^int [^String s ^int radix] (- (int/parse s .radix radix)))
                      (fn ^int [^String s ^int radix] (int/parse s .radix radix))))]
        (cond
          (not (nil? (.group m 2))) 0
          (not (nil? (.group m 3))) (parse (.group m 3) 10)
          (not (nil? (.group m 4))) (parse (.group m 4) 16)
          (not (nil? (.group m 5))) (parse (.group m 5) 8)
          (not (nil? (.group m 7))) (parse (.group m 7) (int/parse ^String (.group m 6)))
          :else (throw (FormatException. (str "Invalid number: " token ".")))))
      (if-some [m (.matchAsPrefix DOUBLE-REGEXP token)]
        (if (.group m 4)
          (throw (FormatException. "BigDecimal not supported yet."))
          (double/parse token))
        (if-some [^Match m (.matchAsPrefix SYMBOL-REGEXP token)]
          (let [g1 (.group m 1)
                g2 (.group m 2)
                g3 (.group m 3)
                g4 (.group m 4)]
            (when (or
                    (and g3 (.endsWith g3 ":/"))
                    (.endsWith g4 ":")
                    (not= -1 (.indexOf token "::" 1)))
              (FormatException. (str "Invalid token: " token)))
            (if g1
              (if-some [nsym (if g3 (resolveAlias *resolver* (symbol nil g3)) (currentNS *resolver*))]
                (keyword (name nsym) g4)
                (FormatException. (str "Invalid token: " token)))
              (if g2
                (keyword g3 g4)
                (symbol g3 g4))))
          (throw (FormatException. (str "Invalid token: " token))))))))

(defn ^#/(Future dynamic) ^:async read
  [^ReaderInput rdr ^int delim]
  (binding [*top-level-form* (nil? *top-level-form*)]
    (loop []
      (if-some [string (await (.read rdr))]
        (let [index (or (some-> (.matchAsPrefix SPACE-REGEXP string) .-end) 0)]
          (if (== index (.-length string))
            (recur)
            (let [ch (.codeUnitAt string index)]
              (if (== delim ch)
                (doto rdr (.unread (.substring string (inc index))))
                (if-some [macro-reader (macros (saget string index))]
                  (do (.unread rdr (.substring string (inc index)))
                      (let [val (await (macro-reader rdr))]
                        (if (== val rdr)
                          (recur)
                          val)))
                  (do (.unread rdr (.substring string index))
                      (-> (await (read-token rdr "")) interpret-token)))))))
        (if (< delim 0)
          rdr
          (throw (FormatException. (str "Unexpected EOF, expected " (String/fromCharCode delim)))))))))

(defn ^#/(Future dynamic) ^:async read-string [^String s]
  (let [controller (new #/(async/StreamController String))
        rdr (make-reader-input controller)]
    (.add controller s)
    (let [res (read rdr -1)]
      (.close controller)
      (await res))))