Don't allow empty intermediate tables

parser_test.go

@@ -203,6 +203,13 @@ func TestDuplicateGroups(t *testing.T) {
 	}
 }
 
+func TestEmptyIntermediateTable(t *testing.T) {
+	_, err := Load("[foo..bar]")
+	if err.Error() != "empty intermediate table" {
+		t.Error("Bad error message:", err.Error())
+	}
+}
+
 func TestMissingFile(t *testing.T) {
 	_, err := LoadFile("foo.toml")
 	if err.Error() != "open foo.toml: no such file or directory" {

toml.go

@@ -88,6 +88,9 @@ func (t *TomlTree) Set(key string, value interface{}) {
 func (t *TomlTree) createSubTree(key string) {
 	subtree := t
 	for _, intermediate_key := range strings.Split(key, ".") {
+		if intermediate_key == "" {
+			panic("empty intermediate table")
+		}
 		_, exists := (*subtree)[intermediate_key]
 		if !exists {
 			var new_tree TomlTree = make(TomlTree)
@@ -121,6 +124,5 @@ func LoadFile(path string) (tree *TomlTree, err error) {
 		s := string(buff)
 		tree, err = Load(s)
 	}
-
 	return
 }