The dot (.) is now known as the context item expression, and might be a node or an atomic value, depending on the current item in the sequence being processed.
点号(.)在这里称为上下文项表达式，可以是节点或者原子值，视处理的序列中的当前项而定。
2
During the single dot cross operation, import the athuard ordinal number arrow, simplify the cross operation of the natural sequence.