关于parval

对parval()，属性指向很困扰
: Y5 N" [( Y2 u2 M1 B比如： baynumber = parval(2)，求注解下，为什么是（2），

0 ^9 H+ h& N/ j! f- F7 j如果levelnuber=?????  求注解。。。。
& b) B7 n( c- d( }& ]  ?For developer use. This command is used inside a function that is called by the nodefunction() command. It returns the parameter passed to nodefunction specified by index as a number. The first additional parameter passed to nodefunction() is parameter 1, the second is parameter 2, etc. Parameters can also be retrieved using parnode() and parstr() for casting them as a treenode and string respectively.
Example: double passedval = parval(3);

9 @. E2 U4 U. p- H. e/ W+ kThis sets passedval equal to the number that was passed to nodefunction() as parameter 3.

函数解释很详细哦他应该就是个传递参数吧