fleshed out main tool

main.go

@@ -1,9 +1,50 @@
 package main
 
+import (
+	"errors"
+	"flag"
+	"fmt"
+	"os"
+
+	"github.com/matryer/moq/package/moq"
+)
+
 func main() {
-	// var (
+	var err error
-	// 	)
+	defer func() {
-	// out := os.Stdout
+		if err != nil {
-	// m := moq.New(".")
+			fmt.Println(err)
-	// m.Mock(out, os.Args...)
+			flag.Usage()
+			os.Exit(1)
+		}
+	}()
+	var (
+		outFile = flag.String("out", "", "output file (default stdout)")
+		pkgName = flag.String("pkg", "", "package name (default will infer)")
+	)
+	flag.Usage = func() {
+		fmt.Println(`moq [flags] destination interface [interface2 [interface3 [...]]]`)
+		flag.PrintDefaults()
+	}
+	flag.Parse()
+	args := flag.Args()
+	if len(args) < 2 {
+		err = errors.New("not enough arguments")
+		return
+	}
+	destination := args[0]
+	args = args[1:]
+	out := os.Stdout
+	if len(*outFile) > 0 {
+		out, err = os.Create(*outFile)
+		if err != nil {
+			return
+		}
+		defer out.Close()
+	}
+	m, err := moq.New(destination, *pkgName)
+	if err != nil {
+		return
+	}
+	err = m.Mock(out, args...)
 }

package/moq/moq.go

@@ -60,6 +60,9 @@ func New(src, packageName string) (*Mocker, error) {
 
 // Mock generates a mock for the specified interface name.
 func (m *Mocker) Mock(w io.Writer, name ...string) error {
+	if len(name) == 0 {
+		return errors.New("must specify one interface")
+	}
 	var objs []*obj
 	for _, pkg := range m.pkgs {
 		i := 0
@@ -75,6 +78,10 @@ func (m *Mocker) Mock(w io.Writer, name ...string) error {
 		}
 		for _, n := range name {
 			iface := tpkg.Scope().Lookup(n)
+			if iface == nil {
+				return fmt.Errorf("cannot find interface %s", n)
+				continue
+			}
 			if !types.IsInterface(iface.Type()) {
 				return fmt.Errorf("%s (%s) not an interface", n, iface.Type().String())
 			}