Re: Ada Networking (General/Design)

[tmoran@acm.org]

>>> If Ada provided higher level socket library with an integrated support of
>>> protected objects and tasks...
>>   What do you mean?
>
>The most difficult and unavoidable part about socket programming is
>tasking. We need reader and writer tasks or else socket-select-driven
>co-routines. The reader and writer parts have to communicate each other in
>some intricate way because it is two tasks but one protocol state machine,
>or one task and many state machines in the case of socket select. There is
>the issue of blocking socket I/O non-abortable by Ada means. All this

The Claw.Sockets package has a simple Socket_Type with
  procedure Open(Socket     : in out Socket_Type;  -- or Server_Type
                 Domain_Name: in     String;  -- or Network_Address_Type
                 Port       : in     Port_Type;
                 Timeout    : in     Duration := 30.0);
and Text_IO style Get/Put for Strings, Input/Output for streams, etc.
It also has a non-blocking Async_Socket_Type with overridable
When_Connect, When_Readable, etc routines, but I find using blocking
sockets with tasks whose structure encodes the state machine is much
simpler.  All the blocking socket routines allow a timeout parameter,
so they in effect poll for data - or a Please_Quit request.  (The
non-blocking routines are of course also polling, via the Windows message
loop.) There are also ftp, pop3, smtp, http, etc packages built on top.