Re: Real syntax problems in Ada

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

"Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote in message 
news:1w3xr2kbz8a19$.wpfoz4p1j1sb.dlg@40tude.net...
> On Tue, 28 Aug 2012 08:14:15 -0700 (PDT), Adam Beneschan wrote:
...
> Speaking of generics, the formal parameter declarations could be more
> regular:
>
> generic
>   type T ...;
>   Object : T;
>
> but
>
> generic
>   with procedure Foo ...;
>   with package Bar ...;
>
> From formal part one could expect following the pattern:
>
>   <name> : <type> [:= <default>]
>
> On the other hand, it is also clear why one would like to keep it visually
> different from the signature of a subprogram.

It's not a case of "liking"; without the "with", the syntax would be 
ambiguous, as a generic unit can be a subprogram. And remember that Ada is 
technically free-form, so the indentation and line-endings are irrelevant. 
So
    generic
         function Foo...
    ...

Is this a generic function with an empty formal part, or a generic formal 
subprogram parameter? Without the "with", you can't tell. You'd need a lot 
of lookahead to figure this out, and clearly such a syntax would be 
error-prone. (Argubly, it's already error-prone, given that I forget the 
"with" roughly 50% of the time and get weird compiler errors, but it 
certainly would be worse without it.)

                                                 Randy.