Allow command replay by hitting <enter>

command/command.go

@@ -23,12 +23,22 @@ func (c *Commands) Register(cmdstr string, cf cmdfunc) {
 	c.cmds[cmdstr] = cf
 }
 
+// Find will look up the command function for the given command input.
+// If it cannot find the command it will defualt to noCmdAvailable().
+// If the command is an empty string it will replay the last command.
 func (c *Commands) Find(cmdstr string) cmdfunc {
 	cmd, ok := c.cmds[cmdstr]
 	if !ok {
+		if cmdstr == "" {
+			return nullCommand
+		}
+
 		return noCmdAvailable
 	}
 
+	// Allow <enter> to replay last command
+	c.cmds[""] = cmd
+
 	return cmd
 }
 
@@ -40,3 +50,7 @@ func exitFunc() error {
 	os.Exit(0)
 	return nil
 }
+
+func nullCommand() error {
+	return nil
+}

command/command_test.go

@@ -37,3 +37,32 @@ func TestCommandRegister(t *testing.T) {
 		t.Fatal("wrong command output")
 	}
 }
+
+func TestCommandReplay(t *testing.T) {
+	cmds := Commands{make(map[string]cmdfunc)}
+	cmds.Register("foo", func() error { return fmt.Errorf("registered command") })
+	cmd := cmds.Find("foo")
+
+	err := cmd()
+	if err.Error() != "registered command" {
+		t.Fatal("wrong command output")
+	}
+
+	cmd = cmds.Find("")
+	err = cmd()
+	if err.Error() != "registered command" {
+		t.Fatal("wrong command output")
+	}
+}
+
+func TestCommandReplayWithoutPreviousCommand(t *testing.T) {
+	var (
+		cmds = Commands{make(map[string]cmdfunc)}
+		cmd  = cmds.Find("")
+		err  = cmd()
+	)
+
+	if err != nil {
+		t.Error("Null command not returned", err)
+	}
+}