help for my project

[Gerald Ang <tmang@student.ecu.edu.au>]

Help is needed for my assignment. Below is a copy of the specificaton
code, please help with the Procedure Add.

with Ada.Text_IO;

with Unchecked_Deallocation;

generic

type Symbol is (<>);

package Symbolized_Search_Tree is

type Tree is private;

type Symbol_Array is array(Integer range <>) of Symbol;

type Sequence is access Symbol_Array;

type Sequence_Array is array(Integer range <>) of Sequence;

package Symbol_IO is new Ada.Text_IO.Enumeration_IO(Enum => Symbol);

procedure Add(A_Tree: in out Tree;
                            Symbols: in Symbol_Array;
                            Result: out Integer);

  -- adds Symbols' non-shared elements to A_Tree and sets marker
  --
  -- if no Symbols
  -- then
  --   Result:= -1
  --   return
  -- end if
  --
 -- if no A_Tree nodes
  -- then
  --   create root node, non-leaf nodes, leaf node
  --   assign Symbols' elements to root node, non-leaf nodes
  --   assign True to leaf node marker
  --   Result:= number of nodes created
  --   return
  -- end if
  --
  -- determine number of Symbols' elements contained in A_Tree
  --
  -- if A_Tree contains all Symbols' elements and True marker
  -- then
  --   Result:= -2
  --   return
  -- end if
  --
  -- if A_Tree contains all Symbols' elements and False marker
  -- then
  --   assign True to marker
  --   Result:= 0
  --   return
  -- end if
  --
  -- if A_Tree contains some of Symbols' elements
  -- then
  --   augment differing non-root node
  --   create non-leaf nodes, leaf nodes
  --   assign Symbols' tail elements to non-root node, non-leaf nodes
  --   assign True to leaf node marker
  --   Result:= number of nodes augmented/created
  --   return
  -- end if
  --
  -- if A_Tree contains none of Symbols' elements
  -- then
  --   augment root node
  --   create non-leaf nodes, leaf node
  --   assign Symbols' elements to root node, non-leaf nodes
  --   assign True to leaf node marker
  --   Result:= number of nodes augmented/created
  --   return
  -- end if


private

  type Node(Length: Integer);

  type Tree is access Node;

  type Tree_Array is array (Integer range <>) of Tree;

  type Node(Length: Integer) is
    record
      Marker: Boolean;
      Symbols: Symbol_Array(1..Length);
      Subtrees: Tree_Array(1..Length);
    end record;
  -- a leaf node has Length = 0 and Marker = True
  -- a partial-leaf node has Length > 0 and Marker = True
  -- a non-leaf node has Length > 0 and Marker = False
  -- for 1 <= I <= Length-1, Node.Symbols(I) < Node.Symbols(I+1)

  Null_Tree: constant Tree:= null;

  procedure Deallocate is

    new Unchecked_Deallocation(Object=>Node,
                                                    Name=>Tree);

end Symbolized_Search_Tree;