complex numbers no longer require a 0+ prefix

node.go

@@ -284,10 +284,8 @@ func (n *numberNode) Type() nodeType {
 
 func (n *numberNode) parse(p *parser) error {
 	t := p.next()
-	if t.t != t_real_number {
+	switch t.t {
-		return fmt.Errorf("unexpected %s token while parsing number", t.t)
+	case t_real_number:
-	}
-
 		if p.peek().t == t_imaginary_number {
 			n.t = num_complex
 			s := t.s + p.next().s
@@ -296,6 +294,15 @@ func (n *numberNode) parse(p *parser) error {
 			}
 			return nil
 		}
+	case t_imaginary_number:
+		n.t = num_complex
+		if _, err := fmt.Sscan("0+"+t.s, &n.c); err != nil {
+			return fmt.Errorf("ungood imaginary number format %s: %s", t.s, err)
+		}
+		return nil
+	default:
+		return fmt.Errorf("unexpected %s token while parsing number", t.t)
+	}
 
 	i, err := strconv.ParseInt(t.s, 0, 64)
 	if err == nil {

parse.go

@@ -13,6 +13,7 @@ const ()
 var nodes = map[tokenType]func(p *parser) node{
 	t_string:           func(p *parser) node { return new(stringNode) },
 	t_real_number:      func(p *parser) node { return new(numberNode) },
+	t_imaginary_number: func(p *parser) node { return new(numberNode) },
 	t_list_start:       func(p *parser) node { p.next(); return &listNode{} },
 	t_object_start:     func(p *parser) node { p.next(); return &objectNode{} },
 	t_variable:         func(p *parser) node { return new(variableNode) },