This class defines a member function within a DeepSee query.
A "member" function is a function that is syntactically part of a member: member.FUNC or member.FUNC(a)
These are sometimes referred to as operators within MDX.
Test if function metadata is in the DeepSeeFunctionGLVN global. If not, put it there.
Return the member provider object associated with this node.
Execute the pre-processing logic for this node.
Convert this node to its text representation.