Re: xor

[Georg Bauhaus <rm.dash-bauhaus@futureapps.de>]

On 28.03.12 14:18, Michael Moeller wrote:

>  While this example compiles without complaints it
> doesn't work with procedures declared in my package. How can I
> make Sequential_IO visible there?

Instantiate Sequential_IO where you need it:
If the instance is needed in several packages,
one solution is to create the instance at library level
(for GNAT, read: in a file that only declares UB_IO).
Then, add a with clause for this instance (UB_IO)
everywhere you need visibility of UB_IO.
(This is what context clauses are about; the other
part of visibility is nesting.)

-->8--
with Package_Defining_UByte;

package UB_IO is new Sequential_IO (Package_Defining_UByte.Ubyte);
--8<--


with UB_IO;
package One is ...

with UB_IO;
package Two is ...



> Its a little strange, though, how dead easy coding concurrency
> on a Sun machine was recently while I'm not able to write out
> some silly bytes using the very same language.

This is not unusual, I think, insofar as virtually every language
requires some effort when I/O is more than "print". Python,
Java, Ada, C, C++, they all have some frowned upon simple I/O procedures,
and then the real thing. The latter takes time getting used to.

(A really good .NET programmer (C#) told me that, now that he
needed to rewrite some software in Java (after a company takeover),
he noticed that he didn't know the first things about formatting
numbers in Java... Of course, he knew about formatting in general
which made learning easier for him.)