I am using GP section of ECJ. I am looking for functions that help me as

1. Delete a GPNode from a GPTree. The function should find the node in the
tree and remove that, then update children field of parent and also update
argposition (and other details) of sibling. Note that the node is extracted
before from tree and we know it is surely in the tree.

2. Add a new created GPNode to a proper position in the tree. The function
should find the right position in the tree (probably based on parent type
of new node), and add node as a new child of its new parent. It should also
update Argposition (and other details) of its new sibling if they are not

Even functions that can help in doing some parts can be very useful.