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Suspension #334

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Suspension #334

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c46384d
introducing the suspension api
cgrand Dec 19, 2017
b48a94e
upgrade works!
cgrand Dec 20, 2017
d4ef64e
Tie print-fns to sessions and remove the global cljsSender.
cgrand Dec 20, 2017
6b10196
disable prompt while suspended
cgrand Dec 21, 2017
7d5cce3
Handle newlines between repl and upgrade.
cgrand Dec 21, 2017
4eb9aa9
pleasing yarn lint
cgrand Dec 21, 2017
5a29401
tighter spill!
cgrand Dec 21, 2017
6732fad
Passing type checks
cgrand Dec 21, 2017
8f8eec4
comment the purpose of each arity
cgrand Dec 21, 2017
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210 changes: 150 additions & 60 deletions src/cljs/snapshot/lumo/repl.cljs
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Original file line number Diff line number Diff line change
Expand Up @@ -646,6 +646,57 @@
"Wrap wfn around all (fn) values in fns hashmap."
(into {} (for [[k v] fns] [k (wfn v)])))

;; --------------------
;; REPL upgrade

(deftype ^:private SuspensionRequest [f])

(defn suspension-request? [x] (instance? SuspensionRequest x))

(defn suspension-request [f] (SuspensionRequest. f))

(defprotocol AsyncReader
"Asynchronous stream of strings."
(read-chars [r f] "Calls f with a string or nil (EOF)")
(pushback [r s] "Unread s"))

(defn yield-control [suspension-request async-reader resume-cb]
((.-f suspension-request) async-reader resume-cb))

(defn- create-async-pipe []
(let [front #js []
back #js []
cb (volatile! nil)
spill! #(when-some [s (.pop back)] (.push front s) (recur))]
#js [(fn line-cb
([] ; 0-arg is called on resumption by repl.js to retrieve the content of the buffer
(spill!)
(when-some [last (.pop front)]
; remove last newline since repl/readline assumes no trailing newline
(let [n (dec (.-length last))]
(.push front (if (= \newline (.charAt last n)) (subs last 0 n) last))))
(.join front ""))
([s] ; 1-arg is called by repl.js when new input is available
(when (and s (not= "" s)) ; TODO handle EOF
(let [s (str s "\n")]
(if-some [f @cb]
(do (vreset! cb nil) (f s))
(if (pos? (.-length front))
(.push back s)
(.push front s)))))))
(reify AsyncReader
(read-chars [r f]
(if-some [s (.pop front)]
(f s)
(do
(spill!)
(if-some [s (.pop front)]
(f s)
(vreset! cb f)))))
(pushback [r s]
(when (and s (not= "" s))
(.push front s))))]))

(declare execute-path)

(def ^:private repl-special-fns
Expand Down Expand Up @@ -917,7 +968,7 @@
(let [{:keys [ex-kind]} (ex-data e)]
(keyword-identical? ex-kind :eof)))

(defn- read-chars
(defn- read-all-chars
[reader]
(let [sb (StringBuffer.)]
(loop [c (rt/read-char reader)]
Expand Down Expand Up @@ -982,7 +1033,7 @@
r/*data-readers* (merge tags/*cljs-data-readers* (load-data-readers! env/*compiler*))
r/resolve-symbol ana/resolve-symbol
r/*alias-map* (current-alias-map)]
[(r/read {:read-cond :allow :features #{:cljs}} reader) (read-chars reader)])))
[(r/read {:read-cond :allow :features #{:cljs}} reader) (read-all-chars reader)])))

(defn- ns-for-source [source]
(let [[ns-form] (repl-read-string source)
Expand All @@ -1009,7 +1060,9 @@
:*2 *2
:*3 *3
:*e *e
:ns @current-ns})
:ns @current-ns
:*print-fn* *print-fn*
:*print-err-fn* *print-err-fn*})

(defn- set-session-state!
"Sets the session state given a sesssion state map."
Expand All @@ -1024,7 +1077,9 @@
(set! *2 (:*2 session-state))
(set! *3 (:*3 session-state))
(set! *e (:*e session-state))
(vreset! current-ns (:ns session-state)))
(vreset! current-ns (:ns session-state))
(set! *print-fn* (:*print-fn* session-state))
(set! *print-err-fn* (:*print-err-fn* session-state)))

(def ^{:private true
:doc "The default state used to initialize a new REPL session."}
Expand All @@ -1044,7 +1099,10 @@
(defn- set-session-state-for-session-id!
"Sets the session state for a given session."
[session-id]
(set-session-state! (get @session-states session-id @default-session-state)))
(set-session-state! (or (get @session-states session-id)
(assoc @default-session-state
:*print-fn* *print-fn*
:*print-err-fn* *print-err-fn*))))

(defn- capture-session-state-for-session-id
"Captures the session state for a given session."
Expand Down Expand Up @@ -1113,53 +1171,82 @@
(handle-error (ex-info (str "Could not load file " file) {}) true)))))

(defn- execute-text
[source {:keys [expression? print-nil-result? filename session-id] :as opts}]
(try
(set-session-state-for-session-id! session-id)
(binding [ana/*cljs-warning-handlers* (if expression?
[warning-handler]
[ana/default-warning-handler])
cljs/*eval-fn* caching-node-eval
cljs/*load-fn* load
ana/*cljs-ns* @current-ns
*ns* (create-ns @current-ns)
env/*compiler* st
r/resolve-symbol ana/resolve-symbol
tags/*cljs-data-readers* (merge tags/*cljs-data-readers* (load-data-readers! env/*compiler*))
r/*alias-map* (current-alias-map)]
(let [form (and expression? (first (repl-read-string source)))
eval-opts (merge (make-eval-opts)
(when expression?
{:context :expr
:def-emits-var true}))]
(if (repl-special? form)
((get repl-special-fns (first form)) form (merge opts eval-opts))
(cljs/eval-str
st
source
(cond
expression? source
filename (or (ns-for-source source) filename)
:else "source")
eval-opts
(fn [{:keys [ns value error] :as ret}]
(if-not error
(when expression?
(when (or (true? print-nil-result?)
(not (nil? value)))
(js/$$LUMO_GLOBALS.doPrint print-value value))
(process-1-2-3 form value)
(when (def-form? form)
(let [{:keys [ns name]} (meta value)]
(swap! st assoc-in [::ana/namespaces ns :defs name ::repl-entered-source] source)))
(vreset! current-ns ns))
(handle-error error true)))))))
(catch :default e
;; `;;` and `#_`
(when-not (identical? (.-message e) "Unexpected EOF.")
(handle-error e true)))
(finally (capture-session-state-for-session-id session-id)))
nil)
[source {:keys [expression? print-nil-result? filename session-id host-yield-control] :as opts}]
(let [suspended (volatile! false)]
(try
(set-session-state-for-session-id! session-id)
(binding [ana/*cljs-warning-handlers* (if expression?
[warning-handler]
[ana/default-warning-handler])
cljs/*eval-fn* caching-node-eval
cljs/*load-fn* load
ana/*cljs-ns* @current-ns
*ns* (create-ns @current-ns)
env/*compiler* st
r/resolve-symbol ana/resolve-symbol
tags/*cljs-data-readers* (merge tags/*cljs-data-readers* (load-data-readers! env/*compiler*))
r/*alias-map* (current-alias-map)]
(let [form (and expression? (first (repl-read-string source)))
eval-opts (merge (make-eval-opts)
(when expression?
{:context :expr
:def-emits-var true}))]
(if (repl-special? form)
((get repl-special-fns (first form)) form (merge opts eval-opts))
(cljs/eval-str
st
source
(cond
expression? source
filename (or (ns-for-source source) filename)
:else "source")
eval-opts
(fn eval-cb [{:keys [ns value error] :as ret}]
(when @suspended
(set-session-state-for-session-id! session-id))
(if (and expression? (suspension-request? value))
(if host-yield-control
(if-let [re-yield @suspended]
(re-yield value)
(do
(capture-session-state-for-session-id session-id)
; host-yield-control is the function for readline yielding control
; this could be avoided by using .once and .pause but readline seems to have
; issues with pauses, see https://github.com/nodejs/node-v0.x-archive/issues/8340
(host-yield-control
(fn [async-reader done-cb]
(let [resume #(try
(eval-cb %)
(finally
; eval-cb may have resuspended (see re-yield above)
(when-not @suspended (done-cb))))]
(vreset! suspended #(yield-control % async-reader resume))
(yield-control value async-reader resume))))))
(throw (js/Error. "This REPL can't be upgraded.")))
(try
(vreset! suspended false)
(if-not error
(when expression?
(when (or (true? print-nil-result?)
(not (nil? value)))
(js/$$LUMO_GLOBALS.doPrint print-value value))
(process-1-2-3 form value)
(when (def-form? form)
(let [{:keys [ns name]} (meta value)]
(swap! st assoc-in [::ana/namespaces ns :defs name ::repl-entered-source] source)))
(vreset! current-ns ns))
(handle-error error true))
(finally
(when @suspended
(capture-session-state-for-session-id session-id))))))))))
(catch :default e
;; `;;` and `#_`
(when-not (identical? (.-message e) "Unexpected EOF.")
(handle-error e true)))
(finally
(when-not @suspended
(capture-session-state-for-session-id session-id))))
nil))

(defn- execute-source
[source-or-path {:keys [type] :as opts}]
Expand All @@ -1168,14 +1255,17 @@
(execute-text source-or-path opts)))

(defn- ^:export execute
[type source-or-path expression? print-nil-result? setNS session-id]
(clear-fns!)
(when setNS
(vreset! current-ns (symbol setNS)))
(execute-source source-or-path {:type type
:expression? expression?
:print-nil-result? print-nil-result?
:session-id session-id}))
([type source-or-path expression? print-nil-result? setNS session-id]
(execute type source-or-path expression? print-nil-result? setNS session-id nil))
([type source-or-path expression? print-nil-result? setNS session-id host-yield-control]
(clear-fns!)
(when setNS
(vreset! current-ns (symbol setNS)))
(execute-source source-or-path {:type type
:expression? expression?
:print-nil-result? print-nil-result?
:session-id session-id
:host-yield-control host-yield-control})))

(defn- ^:export is-readable?
[form]
Expand Down
41 changes: 23 additions & 18 deletions src/js/cljs.js
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Original file line number Diff line number Diff line change
Expand Up @@ -207,35 +207,31 @@ function setRuntimeOpts(opts: CLIOptsType): void {
);
}

let cljsSender: stream$Writable;

function printFn(...args: string[]): void {
if (utilBinding.watchdogHasPendingSigint()) {
throw interruptSentinel;
}
cljsSender.write(args.join(' '));
function mkPrintFn(cljsSender: stream$Writable): () => void {
return (...args: string[]): void => {
if (utilBinding.watchdogHasPendingSigint()) {
throw interruptSentinel;
}
cljsSender.write(args.join(' '));
};
}

function printErrFn(...args: string[]): void {
if (utilBinding.watchdogHasPendingSigint()) {
throw interruptSentinel;
}

process.stderr.write(args.join(' '));
}
const printErrFn = mkPrintFn(process.stderr);
const printOutFn = mkPrintFn(process.stdout);

export function setPrintFns(stream?: stream$Writable): void {
if (stream == null || stream === process.stdout) {
cljsSender = process.stdout;
// $FlowIssue: context can have globals
ClojureScriptContext.cljs.core.set_print_fn_BANG_(printOutFn);
// $FlowIssue: context can have globals
ClojureScriptContext.cljs.core.set_print_err_fn_BANG_(printErrFn);
} else {
cljsSender = stream;
const printFn = mkPrintFn(stream);
// $FlowIssue: context can have globals
ClojureScriptContext.cljs.core.set_print_fn_BANG_(printFn);
// $FlowIssue: context can have globals
ClojureScriptContext.cljs.core.set_print_err_fn_BANG_(printFn);
}
// $FlowIssue: context can have globals
ClojureScriptContext.cljs.core.set_print_fn_BANG_(printFn);
}

function initClojureScriptEngine(opts: CLIOptsType): void {
Expand Down Expand Up @@ -263,13 +259,16 @@ function initClojureScriptEngine(opts: CLIOptsType): void {
setRuntimeOpts(opts);
}

export type AsyncReader = {};

export function execute(
code: string,
type?: string = 'text',
expression?: boolean = true,
printNilResult?: boolean = true,
sessionID?: number = 0,
setNS?: string,
yieldControl?: (f: (async_reader: AsyncReader, resume_cb: ()=>void) => void) => void,
): void {
// $FlowIssue: context can have globals
return ClojureScriptContext.lumo.repl.execute(
Expand All @@ -279,6 +278,7 @@ export function execute(
printNilResult,
setNS,
sessionID,
yieldControl,
);
}

Expand Down Expand Up @@ -315,6 +315,11 @@ export function clearREPLSessionState(sessionID: number): void {
return ClojureScriptContext.lumo.repl.clear_state_for_session(sessionID);
}

export function createAsyncPipe(): [(s?: string)=>string, AsyncReader] {
// $FlowIssue: context can have globals
return ClojureScriptContext.lumo.repl.create_async_pipe();
}

function executeScript(
code: string,
type: string,
Expand Down
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