more updates and renaming

Former-commit-id: 8c194821906b2170df92672fe9dfb9d710640659

frontmatter/types.go

@@ -0,0 +1,13 @@
+package frontmatter
+
+import "reflect"
+
+// isMap checks if some variable is a map
+func isMap(sth interface{}) bool {
+	return reflect.ValueOf(sth).Kind() == reflect.Map
+}
+
+// isSlice checks if some variable is a slice
+func isSlice(sth interface{}) bool {
+	return reflect.ValueOf(sth).Kind() == reflect.Slice
+}