Re: New to Ada, why these warning messages?

[Bob Duff <bobduff@theworld.com>]

Paul Rubin <no.email@nospam.invalid> writes:

> Is there a summary somewhere of what Ada added to Pascal?

Mike Woodger told me that chapters 2-6 were supposed to be
(very roughly) the Pascal subset of Ada, and chapters 7-14
were the new stuff.  That's for Ada 83 -- since then, various
things have been added, such as object-oriented features in
chapter 3, which doesn't correspond to Pascal.  I'm talking
about Jensen and Wirth Pascal, not Delphi or other dialects.

Off the top of my head, features in Ada 83 but not Pascal: a more
elaborate type system, dynamic arrays, discriminant-dependent arrays,
bounds are not part of array type, slices, fixed-point types,
user-defined numeric types, aggregates, full coverage rules, better
notion of parameter modes (especially: pass-by-reference allowed for
'in' parameters), packages, private types, limited types, renaming,
multi-tasking, separate compilation(!), generics, representation
clauses, most of the pragmas and attributes.

The AARM has a list at the end of each section of features added since
Ada 83.

>...I also
> haven't understood why the books are so thick, or why Ada has such a
> reputation of being hard to compile.  Any simple summary?  Thanks!

No simple summary.  Ada is a big language, and it's hard to implement.
Other languages are worse in that regard, though -- C++ comes to mind.

If you read the Ada RM (preferably the Annotated version -- AARM), you
will see.  Or for just a taste, read section 3.10.2, and think about how
to implement it.  ;-)

- Bob