Re: Pascal type sets in Ada?

[haven.umd.edu!darwin.sura.net!cs.ucf.edu!crigler@ames.arc.nasa.gov (Jame s Crigler)]

In article <1992Sep21.050905.1@cc.utah.edu> eyring@cc.utah.edu writes:
>This is a question I have had for some time.
>Why doesn't Ada include Pascal type sets?
>There must be a reason.  Or how does one 
>do Pascal sets in Ada?  Any ideas?
>-- 
>>Bob Witmer

I think Booch discusses this (or something simalar) in _Software_Engineering_
In_Ada (my least favorite Ada book).  The essence is to create a generic
that defines a set to be a BOOLEAN array, then use pragma PACK to lower the
space overhead.

E. g.:

generic
  type BASE is (<>);
package SET_PKG is 
  type SET_TYPE is array (BASE) of BOOLEAN;
  pragma PACK (SET_TYPE);
  function "+" (S : SET_TYPE; I : BASE) return SET_TYPE;  -- Add a member
  function "-" (S : SET_TYPE; I : BASE) return SET_TYPE;  -- Remove a member
  function IS_A_SUBSET (S : SET_TYPE; POTENTIAL : SET_TYPE) return BOOLEAN;
  function IS_A_MEMBER (S : SET_TYPE; I : BASE) return BOOLEAN;
  ...
end SET_PKG;

Jim Crigler
----------------------------------------
Guinan is Q's mother.