-Generally, whitespace and comments are alowed everywhere except in variable names and inside expressions.
-Also, COMMENT must not contain '\n'.
+Generally, whitespace and comments are alowed everywhere except in variable names and inside expressions,
+``\\n`` ends a ``COMMENT``.
+
+``FILE``, ``BLOCK``, ``STATEMENT``, ``OPERATION``, ``SUBTREE``, ``CONDITION``, ``FORMULA``, ``AND``, ``OR``
+and ``NOT`` ignore any preceding whitespace.