Appendix E Simple_io package

The simple_io package is the simplified I/O package used by the first year students. 
It attempts to provide facilities similar to that found in the Turbo Pascal 
environment.

with text_io;

package simple_io is

	data_error: exception renames text_io.data_error;

	procedure get_line( item :   out integer);
	procedure get_line( file :in out text_io.file_type;
				 item :   out integer);
    
	procedure get_line( item :   out float);
	procedure get_line( file :in out text_io.file_type;
				 item :   out float);
    
    
	procedure get_line( item :   out string);
	procedure get_line( file :in out text_io.file_type;
				 item :   out string);
    
	procedure get_line( item :   out character);
	procedure get_line( file :in out text_io.file_type;
				 item :   out character);
 
	procedure get( item :   out character)
				renames text_io.get;

	procedure skip_line(spacing :in text_io.positive_count:=1)
				renames text_io.skip_line;
 

	function end_of_file return boolean 
				renames text_io.end_of_file;
 
	function end_of_line return boolean
				renames text_io.end_of_line;
       
	procedure put( item :in integer;
	               width :in natural := 0);
   
	procedure put( file :in out text_io.file_type;
	               item :in integer;
	               width :in natural := 0);


	default_fore :natural := 6;
	default_aft :natural := 2;
	default_exp :natural := 0;

	procedure put( item :in float;
	               fore :in natural := default_fore;
                      aft :in natural := default_aft;
                      exp :in natural := default_exp);

	procedure put( file :in out text_io.file_type;
	               item :in float;
	               fore :in natural := default_fore;
	               aft :in natural := default_aft;
	               exp :in natural := default_exp);
   

	procedure put( item :in string;
	               width :in natural := 0);

	procedure put( item :in character);

	procedure new_line(line_count:in positive := 1); 
	------------------------------------------------------------
	-- The following subprograms are used for screen and 
keyboard control
	--
	subtype row_range is integer range 0..23;
	subtype column_range is integer range 0..79;
 
	procedure move( row :in row_range;
	                col :in column_range);
	procedure home;
	-- moves the cursor to row_range'first, column_range'first 
 
	procedure clear_screen;
	-- clears the screen and sends the cursor home
	subtype color_range is integer range 30..37;
	black   :constant color_range := 30;
	red     :constant color_range := 31;
	green   :constant color_range := 32;
	yellow  :constant color_range := 33;
	blue    :constant color_range := 34;
	magenta :constant color_range := 35;
	cyan    :constant color_range := 36;
	white   :constant color_range := 37;
  
	procedure text_color(color :color_range);

	function current_text_color return color_range;
	-- what is the current color used for displaying text?
 
	procedure get_cursor_pos(row :   out row_range;
	                         col :   out column_range);
	-- where is the cursor currently positioned?
  
	procedure wait_for_keypress;
	-- waits until the user hits a single key
 
	function read_key return character;
	-- returns the key the user types without needing
	-- the user to press the return key.
 
end simple_io;