Fix scanning of float with leading zero (#486)

parser.go

@@ -1056,7 +1056,7 @@ func (p *parser) parseTime(b []byte) ([]byte, error) {
 func (p *parser) scanIntOrFloat(b []byte) (ast.Reference, []byte, error) {
 	i := 0
 
-	if len(b) > 2 && b[0] == '0' {
+	if len(b) > 2 && b[0] == '0' && b[1] != '.' {
 		var isValidRune validRuneFn
 		switch b[1] {
 		case 'x':

parser_test.go

@@ -49,6 +49,21 @@ func TestParser_AST_Numbers(t *testing.T) {
 			input: `0b11010110`,
 			kind:  ast.Integer,
 		},
+		{
+			desc:  "float zero",
+			input: `0.0`,
+			kind:  ast.Float,
+		},
+		{
+			desc:  "float positive zero",
+			input: `+0.0`,
+			kind:  ast.Float,
+		},
+		{
+			desc:  "float negative zero",
+			input: `-0.0`,
+			kind:  ast.Float,
+		},
 		{
 			desc:  "float pi",
 			input: `3.1415`,