Re: Charles container library usage examples

[David Trudgett <wpower@zeta.org.au.nospamplease>]

Hi Simon,

Simon Wright <simon@pushface.org> writes:

> Matthew Heaney <matthewjheaney@earthlink.net> writes:
>
>> David Trudgett <wpower@zeta.org.au.nospamplease>  writes:
>
>>> The first thing I had in mind to do was to create a simple map, for
>>> example, to translate the following Common Lisp:
>>> 
>>> (defvar *side-corners*
>>>   '((2 (1 3))
>>>     (4 (1 7))
>>>     (6 (3 9))
>>>     (8 (7 9))))
>>
>> You can use a map, instantiated with type Integer as the key and an
>> instantiation of a list as the element.  Either the hashed map or the
>> ordered map would suffice.
>
> I would have used (for example)
>
>   type Axis is (X, Y);
>   type Coordinate is range 1 .. 8;
>   type Position is array (Axis) of Coordinate;
>

> as the element type (making some assumptions about the problem!). 

They do look like coordinates, don't they? :-) Does the following shed
any light?


   procedure Print_Board_Key is
   begin

      New_Line;
      Put("The board squares are numbered as follows:");
      New_Line(2);
      Put("  1 | 2 | 3 "); New_Line;
      Put(" -----------"); New_Line;
      Put("  4 | 5 | 6 "); New_Line;
      Put(" -----------"); New_Line;
      Put("  7 | 8 | 9 "); New_Line(2);

   end Print_Board_Key;


It's a simple tic tac toe game I'm playing around with to learn
Ada. I'm planning to put a GUI onto it before I'm finished with it!


> No need to have a list as the element if the problem doesn't call
> for it (though good to be able to if needed, of course).

It's a learning exercise, so doing things the hard way is not a
problem! :-) I'm just a bit surprised that adding a map and a list to
a program is turning into a major undertaking. I'm sure I'll get
there, though. I might have to do some more study on generics, though
I was hoping to be able to just *use* a map without having to have
detailed knowledge of how generics work.

Cheers,

David


-- 

David Trudgett
http://www.zeta.org.au/~wpower/

No great cause is ever won or lost. The battle must always be renewed
and the creed restated... For some things are universal, catholic and
undying... These do not age or pass out of fashion, for they symbolize
eternal things. They are the guardians of the freedom of the human
spirit, the proof of what our mortal frailty can achieve.

    -- John Buchan, biographer of Montrose