Re: Two ideas for the next Ada Standard

[dewar@cs.nyu.edu (Robert Dewar)]

Jonas says

"I just state a fact of my own Ada code, it could be that I have
not yet learnt how to write good Ada code. In Ada, pointers are
distinct types which differs from C/C++,  eg:

type X1A is access X;
type X2A is access X;
X1P : X1A;
X2P : X2A;

To use X1P and X2P together often requires conversions."

OK, now we begin to see why you are using so many unnecessary conversions.
Why are X1A and X2A here separate types. They should only be separate types
if they are conceptually different types. If you have to convert from one
to the other at all frequently, this shows that they are NOT conceptually
different types, and you should either use a single type, or use subtypes.

Did you have a reason for making separate types? Or is it just that you
don
't know how subtypes work, or somehow feel that separate types for
everything is the Ada way? [it is not!]

If you want the effect of only a single access type for a given type, then
make a package that declares this type, and with it from everywhere that
needs to use this type. Often you can package up a bunch of related
types into a single package when following this approach.

It definitely sounds like the conversions around your program are
your own doing and not something that Ada is forcing on you!