Add stub to Evaler; don't flood the terminal when I/O error occurs.

eval/eval.go

@@ -12,6 +12,7 @@ import (
 
 	"github.com/elves/elvish/parse"
 	"github.com/elves/elvish/store"
+	"github.com/elves/elvish/stub"
 	"github.com/elves/elvish/util"
 )
 
@@ -30,6 +31,7 @@ type Evaler struct {
 	global  Namespace
 	modules map[string]Namespace
 	store   *store.Store
+	Stub    *stub.Stub
 }
 
 // EvalCtx maintains an Evaler along with its runtime context. After creation
@@ -50,7 +52,7 @@ func (ec *EvalCtx) evaling(n parse.Node) {
 
 // NewEvaler creates a new Evaler.
 func NewEvaler(st *store.Store) *Evaler {
-	ev := &Evaler{nil, map[string]Namespace{}, st}
+	ev := &Evaler{nil, map[string]Namespace{}, st, nil}
 
 	// Construct initial global namespace
 	pid := String(strconv.Itoa(syscall.Getpid()))

run/run.go

@@ -15,6 +15,7 @@ import (
 	"github.com/elves/elvish/eval"
 	"github.com/elves/elvish/parse"
 	"github.com/elves/elvish/store"
+	"github.com/elves/elvish/stub"
 	"github.com/elves/elvish/sys"
 	"github.com/elves/elvish/util"
 )
@@ -69,6 +70,13 @@ func Main() {
 		}
 	}()
 
+	stub, err := stub.NewStub(os.Stderr)
+	if err != nil {
+		fmt.Println("failed to spawn stub:", err)
+	} else {
+		ev.Stub = stub
+	}
+
 	if len(args) == 1 {
 		script(ev, args[0])
 	} else {
@@ -158,6 +166,9 @@ func interact(ev *eval.Evaler, st *store.Store) {
 				fmt.Println("Falling back to basic line editor")
 				readLine = basicReadLine
 				usingBasic = true
+			} else {
+				fmt.Println("Don't know what to do, pid is", os.Getpid())
+				select {}
 			}
 			continue
 		}