all: handle SystemExit

main.go

@@ -60,6 +60,7 @@ func xmain(args []string) {
 		defer pprof.StopCPUProfile()
 	}
 
+	var err error
 	// IF no args, enter REPL mode
 	if len(args) == 0 {
 
@@ -69,13 +70,46 @@ func xmain(args []string) {
 		fmt.Printf("- go version: %s\n", runtime.Version())
 
 		replCtx := repl.New(ctx)
-		cli.RunREPL(replCtx)
+		err = cli.RunREPL(replCtx)
+	} else {
+		_, err = py.RunFile(ctx, args[0], py.CompileOpts{}, nil)
+	}
+	if err != nil {
+		if py.IsException(py.SystemExit, err) {
+			handleSystemExit(err.(py.ExceptionInfo).Value.(*py.Exception))
+		}
+		py.TracebackDump(err)
+		os.Exit(1)
+	}
+}
 
+func handleSystemExit(exc *py.Exception) {
+	args := exc.Args.(py.Tuple)
+	if len(args) == 0 {
+		os.Exit(0)
+	} else if len(args) == 1 {
+		if code, ok := args[0].(py.Int); ok {
+			c, err := code.GoInt()
+			if err != nil {
+				fmt.Fprintln(os.Stderr, err)
+				os.Exit(1)
+			}
+			os.Exit(c)
+		}
+		msg, err := py.ReprAsString(args[0])
+		if err != nil {
+			fmt.Fprintln(os.Stderr, err)
+		} else {
+			fmt.Fprintln(os.Stderr, msg)
+		}
+		os.Exit(1)
 	} else {
-		_, err := py.RunFile(ctx, args[0], py.CompileOpts{}, nil)
+		msg, err := py.ReprAsString(args)
 		if err != nil {
-			py.TracebackDump(err)
-			os.Exit(1)
+			fmt.Fprintln(os.Stderr, err)
+		} else {
+			fmt.Fprintln(os.Stderr, msg)
 		}
+		os.Exit(1)
 	}
 }

repl/cli/cli.go

@@ -117,7 +117,7 @@ func (rl *readline) Print(out string) {
 }
 
 // RunREPL starts the REPL loop
-func RunREPL(replCtx *repl.REPL) {
+func RunREPL(replCtx *repl.REPL) error {
 	if replCtx == nil {
 		replCtx = repl.New(nil)
 	}
@@ -144,6 +144,10 @@ func RunREPL(replCtx *repl.REPL) {
 		if line != "" {
 			rl.AppendHistory(line)
 		}
-		rl.repl.Run(line)
+		err = rl.repl.Run(line)
+		if err != nil {
+			return err
+		}
 	}
+	return nil
 }

repl/repl.go

@@ -66,7 +66,7 @@ func (r *REPL) SetUI(term UI) {
 }
 
 // Run runs a single line of the REPL
-func (r *REPL) Run(line string) {
+func (r *REPL) Run(line string) error {
 	// Override the PrintExpr output temporarily
 	oldPrintExpr := vm.PrintExpr
 	vm.PrintExpr = r.term.Print
@@ -76,13 +76,13 @@ func (r *REPL) Run(line string) {
 	if r.continuation {
 		if line != "" {
 			r.previous += string(line) + "\n"
-			return
+			return nil
 		}
 	}
 	// need +"\n" because "single" expects \n terminated input
 	toCompile := r.previous + string(line)
 	if toCompile == "" {
-		return
+		return nil
 	}
 	code, err := py.Compile(toCompile+"\n", r.prog, py.SingleMode, 0, true)
 	if err != nil {
@@ -97,20 +97,24 @@ func (r *REPL) Run(line string) {
 				r.previous += string(line) + "\n"
 				r.term.SetPrompt(ContinuationPrompt)
 			}
-			return
+			return nil
 		}
 	}
 	r.continuation = false
 	r.term.SetPrompt(NormalPrompt)
 	r.previous = ""
 	if err != nil {
 		r.term.Print(fmt.Sprintf("Compile error: %v", err))
-		return
+		return nil
 	}
 	_, err = r.Context.RunCode(code, r.Module.Globals, r.Module.Globals, nil)
 	if err != nil {
+		if py.IsException(py.SystemExit, err) {
+			return err
+		}
 		py.TracebackDump(err)
 	}
+	return nil
 }
 
 // WordCompleter takes the currently edited line with the cursor

stdlib/sys/sys.go

@@ -133,7 +133,11 @@ func sys_exit(self py.Object, args py.Tuple) (py.Object, error) {
 		return nil, err
 	}
 	// Raise SystemExit so callers may catch it or clean up.
-	return py.ExceptionNew(py.SystemExit, args, nil)
+	exc, err := py.ExceptionNew(py.SystemExit, args, nil)
+	if err != nil {
+		return nil, err
+	}
+	return nil, exc.(*py.Exception)
 }
 
 const getdefaultencoding_doc = `getdefaultencoding() -> string