Re: generics in Ada 83

["Hyman Rosen" <hyman.rosen@gmail.com>]

Jean-Pierre Rosen wrote:
> The benefit is that if a generic compiles, and the instantiation
> provides parameters that match the contract (of the generic formals),
> then the instantion is *always* OK.

How is that different from templates? If the template compiles,
and the instantiation provides parameters such that all usage
within the template is legal, then the instantiation is OK.
Otherwise the program doesn't compile. Ada has explicit contracts
and C++ does "contract by usage" but in either language, once the
program compiles it is correct.

Supplying contracts in C++ would be vastly more difficult than it
is in Ada, because C++ has a variety of automatic conversions and
because C++ templates can be specialized whereas Ada generics cannot
be.