Re: Don't use the "use" clause

["Randy Brukardt" <randy@rrsoftware.com>]

"Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote in message
news:1wq3tkzfwt0bw.1ad4zqlgln451$.dlg@40tude.net...
...
> But Standard cannot be declared within itself, even conceptually! (:-))
> Anyway nested declarations are equivalent to "use"-ing.

Not really, direct visibility is a hiding relationship (new items hide old
ones); use is a canceling relationship.

> I must admit, that I never managed to understand the point of use-haters.
> (Probably because they don't have any (:-)) The packages comprise a tree.
> With "use"-ing it is levered to a DAG. I would *really* like to be able to
> do it without "use" as well, i.e. to have children of multiple parents.
But
> that's aside. Is the point that all nodes along any path need to be
> mentioned? If so, then "use" or not is quite irrelevant. If not then what?
> To keep it a tree, then "with" must be outlawed as well. I don't get it.

For me at least, it is about being able to find declarations sensibly -
without having to rely on fancy tools which necessarily require the code to
be complete and compilable. Thus, strict limits on use clauses. Moreover,
nested (direct) visibility is for the birds, in all of its forms. I want
(and write) prefixes on *all* non-local declarations (with the exception of
operators, which I consider a property more than a separate entity). That
means that I do generally write Parent.operation for things declared in the
parent of a child package. I hate it that the compiler will not allow me to
enforce this.

Does this mean that I don't want child packages? Not at all; child packages
are about extending the parent package. They give access to the entities of
the private part that are otherwise not visibility in any way. I don't want
any direct visibility on the parent, and think it is a mistake that it is
there (it causes various anomolies that we've spent a lot of work
eliminating from packages with just context clause relationships). Indeed, I
probably would have modeled the child unit as a special kind of context
clause, rather than using nesting.

Remember the difference between "visibility" (the ability to use an entities
name) and "direct visibility" (the ability to an entities name without
qualification). I want the former (of course), and only want the latter for
local declarations.

Summary: "visibility" == good; "direct visibility" == bad (well, at least if
not strictly limited).

                             Randy.