-- FILE:	life.adb
-- AUTHOR:	E.Burke
-- DATE:	November, 1996
-- PURPOSE:	Driver procedure for Game of Life

with Grid; 

procedure Life is

-- Package GRID contains generic specification of BOARD and all 
-- operations needed to play the Game of Life
 
package Life_Grid is new GRID (MAX_ROWS => 20, MAX_COLUMNS => 50,
                               MAX_SIZE => 50);
  T  		:  Life_Grid.BOARD;
  Again		:  BOOLEAN;

begin
  Life_Grid.Initialize(T);	-- Set all cells to 'dead' (false)	
  Life_Grid.Input(T);		-- Allow user to input coordinates
				--   of 'alive' cells
  Life_Grid.Output (T);		-- Display cells (initial pattern)	
  Again := Life_Grid.Enquire;	-- Ask user whether to continue
				--  for another update cycle	
  while Again loop
    Life_Grid.Update_Box (T);	-- Change cells to alive or dead depending
				--   on status of neighbors
    Life_Grid.Output (T);	-- Display cells (updated pattern)
    Again := Life_Grid.Enquire;
  end loop;
end Life; 

-- comments by G. Levine

-- You should declare the values that are used to instantiate the Grid,
-- MAX_SIZE, MAX_ROWS, MAX_COLUMNS, as constants (or else allow the player
-- to input their values). 
-- For Reuse, we do not use literals.
-- You might also consider the Ada construct,
-- loop
--     exit when not Life_grid.Inquire;
--     Life_Grid.Update_Box(T);
--     Life_Grid.Output (T);   
-- end loop;

-- I would also recommend an exception handler, when others =>
-- as a feature to guarantee retaining control.