Re: windows ada compiler error

[Jeffrey Carter <spam@spam.com>]

Andrew wrote:

> but I always get the
> raised ADA.IO_EXCEPTION.NAME_ERROR : s-fileio.adb:869
> error

That means there's a problem with your file name. Most likely, you're 
trying to open a file that doesn't exist. Since you're creating the 
file, you probably want to use Create rather than Open.

Your code is full of things that indicate you don't understand basic Ada 
concepts. I'll try to point them out so you can learn about them.

I notice that the code has a number of initialized variables that you 
never assign to. These are called constants, and should be declared as 
such. For example,

>    down: Integer:=10;  -- down map
>    acros: INTEGER:=10; -- across map

should probably be

Down   : constant := 10;
Across : cosntant := 10;

>    for i in 1..down loop
>       for j in 1..acros loop
>          map_array(i,j):='X';
>       end loop;
>    end loop;

You can create a literal for an entire array in Ada:

Map_Array := (others => (others => 'X') );

You don't need to assign element by element. In fact, you can do this 
when you declare the object:

Map_Array : Map_Hold (1 .. Down, 1 .. Across) :=
    (others => (others => 'X') );

When you do need to iterate over an array, you don't need to remember 
what range you declared it with:

for I in Map_Array'range (1) loop
    for J in Map_Array'range (2) loop

For a one-dimensional array, you can just use Name'range, without the "(1)".
> while FoundExit /= 1 loop

This indicates that you don't understand Booleans. You should have

Found_Exit : Boolean := False;
...
loop
    exit when Found_Exit;
...
    Found_Exit := True;

A loop with an exit reads better and is easier to understand than

while not Found_Exit loop

>   Open (map_file, out_FILE, "Map");

This fails if a file name "Map" doesn't already exist.

>    if IS_OPEN(map_file) then

If Open fails, an exception is raised (as you have discovered). 
Therefore, this test will always be true if you get here. You don't need 
it and it complicates your code. Add an exception handler to deal with 
the exceptional case.

>  else
>      Put_Line("Map file didn't open .. Killing Program");
>   end if;

[else to the if above] You can never get here. And if you did, you don't 
kill the program anyway.

Finally, your indentation and capitalization seem random. Regular 
indentation helps the reader see the structure of the program. Regular 
capitalization and putting underlines between words in identifiers makes 
your code easier to read.

-- 
Jeff Carter
"Death awaits you all, with nasty, big, pointy teeth!"
Monty Python & the Holy Grail
20