Re: Let's change semantics of "use type"

[Robert A Duff <bobduff@shell01.TheWorld.com>]

porton@ex-code.com (Victor Porton) writes:

> I am suggesting (for the next Standard) to change the semantics of "use
> type" so that it would make visible not only primitive _operators_, but
> all primitive _operations_.

Why not just "use" the package in which the type is declared?
Why is this worth modifying the language?

> It seems (at the first glance) that changing Standard such the way would
> not make any correct program incorrect.

I think you mean, "...would not change the run-time semantics".
If so, I agree.

>... (However it would make some current
> programs not compilable. If this is too bad, it can be instead denoted as
> "use all type;" for using all operations, not only operators.)
> 
> The rationale is that this is a convenient way for dealing with a type 
> imported from a package without the need of many rename directives.  These
> directives may make a long list and are "dirty" for both writing and
> reading. (Reading this list one may not understand for exactly what is
> present an item of the list and so not know (without experiment with a
> compiler) whether this item can be removed without breaking the program.
> So in certain sense the current Ada is not perfectly readable.) With "use
> all type" programmers will less tend to write multi-level designators
> which are both unreadable (especially when there are several such
> designators in an expression) and error-prone as one may forget y in
> x.y.z (mistakedly writing x.z) and get wrong behavior of the program.

Agreed: long boring sequences of code are evil.

- Bob