eval: Remove default ports from Evaler.

The ports are now made anew each time EvalWithStdPorts is called. This
fixes #571.

eval/eval.go

@@ -35,15 +35,15 @@ const (
 )
 
 const (
-	defaultValueOutIndicator = "▶ "
-	initIndent               = vals.NoPretty
+	defaultValuePrefix = "▶ "
+	initIndent         = vals.NoPretty
 )
 
 // Evaler is used to evaluate elvish sources. It maintains runtime context
 // shared among all evalCtx instances.
 type Evaler struct {
 	evalerScopes
-	evalerPorts
+	valuePrefix  string
 	DaemonClient *daemon.Client
 	modules      map[string]Ns
 	// bundled modules
@@ -60,18 +60,14 @@ type evalerScopes struct {
 
 // NewEvaler creates a new Evaler.
 func NewEvaler() *Evaler {
-	valueOutIndicator := defaultValueOutIndicator
-
 	builtin := builtinNs.Clone()
-	builtin["value-out-indicator"] = vars.NewFromPtr(&valueOutIndicator)
 
 	ev := &Evaler{
+		valuePrefix: defaultValuePrefix,
 		evalerScopes: evalerScopes{
 			Global:  make(Ns),
 			Builtin: builtinNs,
 		},
-		evalerPorts: newEvalerPorts(
-			os.Stdin, os.Stdout, os.Stderr, &valueOutIndicator),
 		modules: map[string]Ns{
 			"builtin": builtin,
 		},
@@ -80,12 +76,15 @@ func NewEvaler() *Evaler {
 		intCh:   nil,
 	}
 
+	builtin["value-out-indicator"] = vars.NewFromPtr(&ev.valuePrefix)
+
 	return ev
 }
 
-// Close releases resources allocated when creating this Evaler.
-func (ev *Evaler) Close() {
-	ev.evalerPorts.close()
+// Close releases resources allocated when creating this Evaler. Currently this
+// does nothing and always returns a nil error.
+func (ev *Evaler) Close() error {
+	return nil
 }
 
 // InstallDaemonClient installs a daemon client to the Evaler.
@@ -142,15 +141,17 @@ func (ev *Evaler) eval(op Op, ports []*Port, src *Source) error {
 	return ec.Eval(op)
 }
 
-// Eval sets up the Evaler with standard ports and evaluates an Op. The supplied
-// name and text are used in diagnostic messages.
-func (ev *Evaler) Eval(op Op, src *Source) error {
-	return ev.EvalWithPorts(ev.ports[:], op, src)
+// EvalWithStdPorts sets up the Evaler with standard ports and evaluates an Op.
+// The supplied name and text are used in diagnostic messages.
+func (ev *Evaler) EvalWithStdPorts(op Op, src *Source) error {
+	stdPorts := newStdPorts(os.Stdin, os.Stdout, os.Stderr, ev.valuePrefix)
+	defer stdPorts.close()
+	return ev.Eval(op, stdPorts.ports[:], src)
 }
 
-// EvalWithPorts sets up the Evaler with the given ports and evaluates an Op.
+// Eval sets up the Evaler with the given ports and evaluates an Op.
 // The supplied name and text are used in diagnostic messages.
-func (ev *Evaler) EvalWithPorts(ports []*Port, op Op, src *Source) error {
+func (ev *Evaler) Eval(op Op, ports []*Port, src *Source) error {
 	// Ignore TTOU.
 	//
 	// When a subprocess in its own process group puts itself in the foreground,
@@ -223,7 +224,7 @@ func (ev *Evaler) SourceText(src *Source) error {
 	if err != nil {
 		return err
 	}
-	return ev.Eval(op, src)
+	return ev.EvalWithStdPorts(op, src)
 }
 
 func readFileUTF8(fname string) (string, error) {

eval/std_ports.go

@@ -12,41 +12,41 @@ const (
 	stderrChanSize = 32
 )
 
-type evalerPorts struct {
-	ports      [3]*Port
-	relayeWait *sync.WaitGroup
+type stdPorts struct {
+	ports       [3]*Port
+	relayerWait *sync.WaitGroup
 }
 
-func newEvalerPorts(stdin, stdout, stderr *os.File, prefix *string) evalerPorts {
+func newStdPorts(stdin, stdout, stderr *os.File, prefix string) stdPorts {
 	stdoutChan := make(chan interface{}, stdoutChanSize)
 	stderrChan := make(chan interface{}, stderrChanSize)
 
-	var relayerWait sync.WaitGroup
+	relayerWait := new(sync.WaitGroup)
 	relayerWait.Add(2)
-	go relayChanToFile(stdoutChan, stdout, prefix, &relayerWait)
-	go relayChanToFile(stderrChan, stderr, prefix, &relayerWait)
+	go relayChanToFile(stdoutChan, stdout, prefix, relayerWait)
+	go relayChanToFile(stderrChan, stderr, prefix, relayerWait)
 
-	return evalerPorts{
+	return stdPorts{
 		[3]*Port{
 			{File: stdin, Chan: ClosedChan},
 			{File: stdout, Chan: stdoutChan, CloseChan: true},
 			{File: stderr, Chan: stderrChan, CloseChan: true},
 		},
-		&relayerWait,
+		relayerWait,
 	}
 }
 
-func relayChanToFile(ch <-chan interface{}, file *os.File, prefix *string, w *sync.WaitGroup) {
+func relayChanToFile(ch <-chan interface{}, file *os.File, prefix string, w *sync.WaitGroup) {
 	for v := range ch {
-		file.WriteString(*prefix)
+		file.WriteString(prefix)
 		file.WriteString(vals.Repr(v, initIndent))
 		file.WriteString("\n")
 	}
 	w.Done()
 }
 
-func (ep *evalerPorts) close() {
+func (ep *stdPorts) close() {
 	ep.ports[1].Close()
 	ep.ports[2].Close()
-	ep.relayeWait.Wait()
+	ep.relayerWait.Wait()
 }

eval/std_ports_test.go

@@ -15,7 +15,7 @@ func TestEvalerPorts(t *testing.T) {
 	defer stderrReader.Close()
 
 	prefix := "> "
-	ep := newEvalerPorts(DevNull, stdout, stderr, &prefix)
+	ep := newStdPorts(DevNull, stdout, stderr, prefix)
 	ep.ports[1].Chan <- "x"
 	ep.ports[1].Chan <- "y"
 	ep.ports[2].Chan <- "bad"

program/shell/script.go

@@ -49,7 +49,7 @@ func script(ev *eval.Evaler, args []string, cmd, compileOnly bool) error {
 		return nil
 	}
 
-	return ev.Eval(op, src)
+	return ev.EvalWithStdPorts(op, src)
 }
 
 var errSourceNotUTF8 = errors.New("source is not UTF-8")

program/web/web.go

@@ -117,7 +117,7 @@ func evalAndCollect(ev *eval.Evaler, code string) (
 		{File: outFile, Chan: outChan},
 		{File: errFile, Chan: eval.BlackholeChan},
 	}
-	err = ev.EvalWithPorts(ports, op, src)
+	err = ev.Eval(op, ports, src)
 
 	outFile.Close()
 	close(outChan)