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CLJS-3470: add async/await support #303

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2 changes: 1 addition & 1 deletion src/main/cljs/cljs/test.cljc
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Original file line number Diff line number Diff line change
Expand Up @@ -262,7 +262,7 @@
cljs.test/IAsyncTest
cljs.core/IFn
(~'-invoke [_# ~done]
~@body)))
((^:async fn [] ~@body)))))

;; =============================================================================
;; Running Tests
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6 changes: 6 additions & 0 deletions src/main/clojure/cljs/analyzer.cljc
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Original file line number Diff line number Diff line change
Expand Up @@ -2314,6 +2314,12 @@ x (not (contains? ret :info)))
meths)
locals (:locals env)
name-var (fn-name-var env locals name)
async (or
;; NOTE: adding async on fn form turns it into a MetaFn which isn't great for interop, let's discourage it - Michiel Borkent
#_(:async (meta form))
(:async (meta name))
(:async (meta (first form))))
env (assoc env :async async)
env (if (some? name)
(update-in env [:fn-scope] conj name-var)
env)
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86 changes: 50 additions & 36 deletions src/main/clojure/cljs/compiler.cljc
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Original file line number Diff line number Diff line change
Expand Up @@ -701,10 +701,16 @@
(emitln then "} else {")
(emitln else "}"))))))

(defn iife-open [{:keys [async]}]
(str (when async "(await ") "(" (when async "async ") "function (){"))

(defn iife-close [{:keys [async]}]
(str "})()" (when async ")")))

(defmethod emit* :case
[{v :test :keys [nodes default env]}]
(when (= (:context env) :expr)
(emitln "(function(){"))
(emitln (iife-open env)))
(let [gs (gensym "caseval__")]
(when (= :expr (:context env))
(emitln "var " gs ";"))
Expand All @@ -723,12 +729,13 @@
(emitln default)))
(emitln "}")
(when (= :expr (:context env))
(emitln "return " gs ";})()"))))
(emitln "return " gs ";"
(iife-close env)))))

(defmethod emit* :throw
[{throw :exception :keys [env]}]
(if (= :expr (:context env))
(emits "(function(){throw " throw "})()")
(emits (iife-open env) "throw " throw (iife-close env))
(emitln "throw " throw ";")))

(def base-types
Expand Down Expand Up @@ -865,7 +872,7 @@
(when (= :return (:context env))
(emitln "return ("))
(when (:def-emits-var env)
(emitln "(function (){"))
(emitln (iife-open env)))
(emits var)
(when init
(emits " = "
Expand All @@ -878,7 +885,8 @@
{:op :the-var
:env (assoc env :context :expr)}
var-ast))
(emitln ");})()"))
(emitln ");"
(iife-close env)))
(when (= :return (:context env))
(emitln ")"))
;; NOTE: JavaScriptCore does not like this under advanced compilation
Expand Down Expand Up @@ -936,18 +944,19 @@

(defn emit-fn-method
[{expr :body :keys [type name params env recurs]}]
(emit-wrap env
(emits "(function " (munge name) "(")
(emit-fn-params params)
(emitln "){")
(when type
(emitln "var self__ = this;"))
(when recurs (emitln "while(true){"))
(emits expr)
(when recurs
(emitln "break;")
(emitln "}"))
(emits "})")))
(let [async (:async env)]
(emit-wrap env
(emits "(" (when async "async ") "function " (munge name) "(")
(emit-fn-params params)
(emitln "){")
(when type
(emitln "var self__ = this;"))
(when recurs (emitln "while(true){"))
(emits expr)
(when recurs
(emitln "break;")
(emitln "}"))
(emits "})"))))

(defn emit-arguments-to-array
"Emit code that copies function arguments into an array starting at an index.
Expand All @@ -968,9 +977,10 @@
(emit-wrap env
(let [name (or name (gensym))
mname (munge name)
delegate-name (str mname "__delegate")]
delegate-name (str mname "__delegate")
async (:async env)]
(emitln "(function() { ")
(emits "var " delegate-name " = function (")
(emits "var " delegate-name " = " (when async "async ") "function (")
(doseq [param params]
(emit param)
(when-not (= param (last params)) (emits ",")))
Expand All @@ -984,10 +994,11 @@
(emitln "}"))
(emitln "};")

(emitln "var " mname " = function (" (comma-sep
(if variadic
(concat (butlast params) ['var_args])
params)) "){")
(emitln "var " mname " = " (when async "async ") "function ("
(comma-sep
(if variadic
(concat (butlast params) ['var_args])
params)) "){")
(when type
(emitln "var self__ = this;"))
(when variadic
Expand Down Expand Up @@ -1024,13 +1035,14 @@
(when (or in-loop (seq recur-params))
(mapcat :params loop-lets)))
(map munge)
seq)]
seq)
async (:async env)]
(when loop-locals
(when (= :return (:context env))
(emits "return "))
(emitln "((function (" (comma-sep (map munge loop-locals)) "){")
(when-not (= :return (:context env))
(emits "return ")))
(emits "return ")))
(if (= 1 (count methods))
(if variadic
(emit-variadic-fn-method (assoc (first methods) :name name))
Expand All @@ -1054,9 +1066,10 @@
(emit-variadic-fn-method meth)
(emit-fn-method meth))
(emitln ";"))
(emitln mname " = function(" (comma-sep (if variadic
(concat (butlast maxparams) ['var_args])
maxparams)) "){")
(emitln mname " = " (when async "async ") "function("
(comma-sep (if variadic
(concat (butlast maxparams) ['var_args])
maxparams)) "){")
(when variadic
(emits "var ")
(emit (last maxparams))
Expand Down Expand Up @@ -1101,32 +1114,33 @@
(defmethod emit* :do
[{:keys [statements ret env]}]
(let [context (:context env)]
(when (and (seq statements) (= :expr context)) (emitln "(function (){"))
(when (and (seq statements) (= :expr context)) (emitln (iife-open env)))
(doseq [s statements] (emitln s))
(emit ret)
(when (and (seq statements) (= :expr context)) (emitln "})()"))))
(when (and (seq statements) (= :expr context)) (emitln (iife-close env)))))

(defmethod emit* :try
[{try :body :keys [env catch name finally]}]
(let [context (:context env)]
(if (or name finally)
(do
(when (= :expr context)
(emits "(function (){"))
(emits (iife-open env)))
(emits "try{" try "}")
(when name
(emits "catch (" (munge name) "){" catch "}"))
(when finally
(assert (not= :const (:op (ana/unwrap-quote finally))) "finally block cannot contain constant")
(emits "finally {" finally "}"))
(when (= :expr context)
(emits "})()")))
(emits (iife-close env))))
(emits try))))

(defn emit-let
[{expr :body :keys [bindings env]} is-loop]
(let [context (:context env)]
(when (= :expr context) (emits "(function (){"))
(when (= :expr context)
(emits (iife-open env)))
(binding [*lexical-renames*
(into *lexical-renames*
(when (= :statement context)
Expand All @@ -1145,7 +1159,7 @@
(when is-loop
(emitln "break;")
(emitln "}")))
(when (= :expr context) (emits "})()"))))
(when (= :expr context) (emits (iife-close env)))))

(defmethod emit* :let [ast]
(emit-let ast false))
Expand All @@ -1166,11 +1180,11 @@
(defmethod emit* :letfn
[{expr :body :keys [bindings env]}]
(let [context (:context env)]
(when (= :expr context) (emits "(function (){"))
(when (= :expr context) (emits (iife-open env)))
(doseq [{:keys [init] :as binding} bindings]
(emitln "var " (munge binding) " = " init ";"))
(emits expr)
(when (= :expr context) (emits "})()"))))
(when (= :expr context) (emits (iife-close env)))))

(defn protocol-prefix [psym]
(symbol (str (-> (str psym)
Expand Down
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