Re: Ada 2012 : aliased parameters ?

[Florian Weimer <fw@deneb.enyo.de>]

* AdaMagica:

> Aliased parameters are meant to cure a deficiency in e.g. containers.
> With current Ada, it's awkward to replace an element of a container.
>
> Now if you make the curser an aliased parameter, the function result
> may dereference safely the cursor, since the cursor and the result are
> tightly coupled,

But this is already the case in Ada 2005.  The lifetime of passed-in
objects extends beyond the immediate need for evaluating the
expression:

| Leaving an execution happens immediately after its completion,
| except in the case of a _master_: the execution of a body other than
| a package_body; the execution of a statement; or the evaluation of
| an expression, function_call, or range that is not part of an
| enclosing expression, function_call, range, or simple_statement
| other than a simple_return_statement.

This is from 7.6.1(3/2).

I've written experimental code which depends on this, providing a
syntactically convenient and efficient form of variadic subprograms.