Fix bugs and add tests for variant parsing

The following cases are now handled properly:
- "false" (yeah, really)
- integers in octal / hexadecimal format
- empty dictionaries with inferred type information

Author: guelfey

variant_lexer.go

@@ -155,7 +155,8 @@ func varLexNormal(l *varLexer) lexState {
 					l.emit(tokBool)
 					continue
 				}
-			} else if l.pos+5 <= len(l.input) {
+			}
+			if l.pos+5 <= len(l.input) {
 				if l.input[l.pos:l.pos+5] == "false" {
 					l.pos += 5
 					l.emit(tokBool)

variant_parser.go

@@ -220,11 +220,13 @@ func varNumAs(s string, sig Signature) (interface{}, error) {
 		return nil, varTypeError{s, sig}
 	}
 	base := 10
-	if strings.HasPrefix(s, "0") {
-		base = 8
-	}
 	if strings.HasPrefix(s, "0x") {
 		base = 16
+		s = s[2:]
+	}
+	if strings.HasPrefix(s, "0") && len(s) != 1 {
+		base = 8
+		s = s[1:]
 	}
 	if isUnsigned {
 		i, err := strconv.ParseUint(s, base, size)
@@ -615,8 +617,8 @@ func (n dictNode) Sigs() sigSet {
 func (n dictNode) Value(sig Signature) (interface{}, error) {
 	set := n.Sigs()
 	if set.Empty() {
-		// no type intofmation -> empty dict
-		return reflect.MakeMap(typeFor(sig.str)), nil
+		// no type information -> empty dict
+		return reflect.MakeMap(typeFor(sig.str)).Interface(), nil
 	}
 	if !set[sig] {
 		return nil, varTypeError{n.String(), sig}

variant_test.go

@@ -34,9 +34,14 @@ var variantParseTests = []struct {
 	v interface{}
 }{
 	{"1", int32(1)},
-	{`"foo"`, "foo"},
 	{"true", true},
+	{"false", false},
 	{"1.0", float64(1.0)},
+	{"0x10", int32(16)},
+	{"1e1", float64(10)},
+	{`"foo"`, "foo"},
+	{`"\a\b\f\n\r\t"`, "\x07\x08\x0c\n\r\t"},
+	{`"\u00e4\U0001f603"`, "\u00e4\U0001f603"},
 	{"[1]", []int32{1}},
 	{"[1, 2, 3]", []int32{1, 2, 3}},
 	{"@ai []", []int32{}},
@@ -48,11 +53,12 @@ var variantParseTests = []struct {
 	{`[[], [""]]`, [][]string{{}, {""}}},
 	{`@a{ss} {}`, map[string]string{}},
 	{`{"foo": 1}`, map[string]int32{"foo": 1}},
+	{`[{}, {"foo": "bar"}]`, []map[string]string{{}, {"foo": "bar"}}},
 	{`{"a": <1>, "b": <"foo">}`,
 		map[string]Variant{"a": MakeVariant(int32(1)), "b": MakeVariant("foo")}},
 	{`b''`, []byte{0}},
 	{`b"abc"`, []byte{'a', 'b', 'c', 0}},
-	{`b"\x01\0002\n"`, []byte{1, 2, '\n', 0}},
+	{`b"\x01\0002\a\b\f\n\r\t"`, []byte{1, 2, 0x7, 0x8, 0xc, '\n', '\r', '\t', 0}},
 	{`[[0], b""]`, [][]byte{{0}, {0}}},
 	{"int16 0", int16(0)},
 	{"byte 0", byte(0)},