nl_tokens: 深度拷贝
pl_tokens: function deepCopy ( obj ) { var result = { } ; var type = toString . call ( obj ) ; if ( ! obj || ( <mask> === "[object RegExp]" ) || typeof obj !== "object" ) return obj ; if ( type === "[object Array]" ) return slice . call ( obj ) ; for ( var k in obj ) { result [ k ] = deepCopy ( obj [ k ] ) } return result ; }