Re: How difficult is ada to learn?

Gene wrote: 

Most people who start with Borland Pascal miss the built-in set and
string data types. Ada gets the same effects with packages, but the
syntax is far less elegant and readable.

I haven't done any Pascal in a while, so I don't remember the syntax for set manipulation, but Ada 2005 will have a set container type. It's an abstract data type, declared in a package in the normal way. It supports union, intersection, etc.

If not having "built-in" syntax is a hardship, then you can always define array-based set operations yourself. For example, suppose we have a set whose element type is Integer, then we can do this:

type Integer_Array is array (Positive range <>) of Integer;

function "+" (IA : Integer) return Integer_Sets.Set is
  S : Set;
begin
  for Indx in IA'Range loop
     S.Include (IA (Indx));
  end loop;

  return S;
end;

Now you can say:

declare
   S1 : Set := +(1, 2, 3);
   S2 : Set := +(2, 3, 4);
   S3 : Set := S1 or S2;
   S4 : Set := S3 and +(1, 3);
   S5 : Set := +(42, 43) or +(44, 45);
begin  ...;

That's not that inelegant.  Not much different from Pascal, as I recall...
.

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