Systems Problem Support

1. The RCX 2 can only hold 32 "global" variables and 16 "local" variables (Where "global" and "local" refer to the SCOPE of the variables):
• ----------------- PROGRAM START -------------------
• .....procedure LegoRover is
• .......Floor : array (1 .. 25) of Integer; ;---------------------Uses 25 global
• .......Left_Wheel : constant Output_Port := Output_A;-----Uses NO variables
• .......White : Integer;------------------------------------Uses 1 global
• .......procedure DoSomething is
• .........TestCase : Boolean;-------------------------------Uses 1 local
• .......begin
• ......... code here
• .......end
• .....begin
• ......... code here
• .....end
• ----------------- PROGRAM START -------------------
2. Do NOT use the word "Matrix" as a variable name. It is used in the Ada2NQC translation process.

3. Do NOT use the following syntax in defining your array type, there is a bug with Ada Minstorms / Ada2NQC translator.
• type Grid is array (1..25) of Integer;
• Floor : Grid;
• USE:
• Floor : array (1..25) of Integer; -- Like in the above short program example.

4. The Ada/Mindstorms translator only supports a nesting level of 1. (This is a limitation stated in the Ada/Mindstorms manual) This means:

procedure MainRoverCode is

procedure Nested1 is

procedure Nested2 is -- I AM ILLEGAL IN ADA/MINDSTORMS!

begin

end;

begin

end;

begin

end;

5. There is no reason to put variables declared constant anywhere else but in the 'MainRoverCode' procedure.

6. The translator is rather inefficient about translating for loops. When using the code:

for I in 1..25 loop

end loop;

The translator will create 2 global variables: one called "I" equal to 1 and another called "I_STOP" equal to 25. You can FORCE a reduction in the number of global variables used by replacing the above for loop code with while loop code:

procedure MainRoverCode is

I : Integer : = 1;

begin

while (I<25) loop

                -- your code

                I:=I+1;

end loop;

end