Re: Ada Pointer Problem

[Benjamin Ketcham <bketcham@drizzle.com>]

Jeffrey Carter <spam@spam.com> wrote:
> 
> The terminology is not snobbishness but precision. The language 
> definition should not unnecessarily constrain implementations. An access 
> value may not necessarily be just a pointer; it may contain bounds 
> information if it designates an unconstrained array type, for example, 
> and there are such implementations.

But even in C, it is already understood (by some, and pedantically
explained to the others on a near-daily basis) that "pointers" are
abstract entities, not necessarily the same as "machine addresses";
some implementations transparently use "fat pointers"; and in all
cases, additional information than the "address" can be considered
to be conceptually contained within the pointer, i.e., the type of
the referenced object, particularly the size/alignment for stride
calculations (though of course that information is typically not actually
carried around in the bit pattern, rather is applied at compile-time).

> There was also a design principle that shorter names were preferable: 
> "task" instead of "thread" or "process", "access" instead of "pointer".

But it's not an "access", it's an "access type".  Longer, plus more
than one word.

> Finally, "is access X" reads better than "is pointer X".

Right, to be grammatical (and to match existing verbal usage) you'd
say "is (a) pointer *to* X".  Of course in the code, you'd say something
much more compact, not involving English words at all: whether that is
an advantage or a disadvantage is obviously the territory of religion!
I know which I prefer, but then I like assembly language too.

Also, seems to me, "pointer" is a noun, "access" is normally a verb.
The nouning of verbs doesn't necessarily make for better reading, IMO.

And finally, "pointer to X" very intuitively describes what the
construct does, in a way that makes sense to the first-year CS student
and the deep hardware engineer alike.  "Access type" seems like obtuse
government terminology, divorced from any physical or intuitive
meaning.  How is one to guess that the "access" is by indirection?
I want to "access" *all* my variables!  What is the opposite of
"access", a no-read/no-write type?  Sounds very Zen.
Are not the indexing of an array, calling of a function, ":=", etc., also
examples of "access methods"?  Shouldn't it really be called the
"indirect access type" or "access-by-reference type"?  Yeah, there
we go, getting to my real criticism of Ada: not verbose enough. ;)

--Benjamin