emulate old yap socket (thanks to Jan code).

docs/yap.tex

@@ -5762,12 +5762,13 @@ interactive control from a pipe or a socket.
 @node Sockets, , I/O Control, I/O
 @subsection Using Sockets From YAP
 
-YAP includes a SICStus Prolog compatible socket interface. This
-is a low level interface that provides direct access to the major socket
-system calls. These calls can be used both to open a new connection in
-the network or connect to a networked server. Socket connections are
-described as read/write streams, and standard I/O built-ins can be used
-to write on or read from sockets. The following calls are available:
+YAP includes a SICStus Prolog compatible socket interface. In YAP-6.3
+this uses the @c{clib} package to emulate the old low level interface that
+provides direct access to the major socket system calls. These calls
+can be used both to open a new connection in the network or connect to
+a networked server. Socket connections are described as read/write
+streams, and standard I/O built-ins can be used to write on or read
+from sockets. The following calls are available:
 
 @table @code
 
@@ -5778,13 +5779,15 @@ to write on or read from sockets. The following calls are available:
 Corresponds to the BSD system call @code{socket}. Create a socket for
 domain @var{DOMAIN} of type @var{TYPE} and protocol
 @var{PROTOCOL}. Both @var{DOMAIN} and @var{TYPE} should be atoms,
-whereas @var{PROTOCOL} must be an integer. The new socket object is
+whereas @var{PROTOCOL} must be an integer.
+The new socket object is
 accessible through a descriptor bound to the variable @var{SOCKET}.
 
-The current implementation of YAP only accepts two socket
-domains: @code{'AF_INET'} and @code{'AF_UNIX'}. Socket types depend on the
+The current implementation of YAP only accepts one socket
+domain: @code{'AF_INET'}. @c and @code{'AF_UNIX'}. 
+Socket types depend on the
 underlying operating system, but at least the following types are
-supported: @code{'SOCK_STREAM'} and @code{'SOCK_DGRAM'}.
+supported: @code{'SOCK_STREAM'} and @code{'SOCK_DGRAM'} (untested in 6.3).
 
 @item socket(+@var{DOMAIN},-@var{SOCKET})
 @findex socket/2
@@ -5812,7 +5815,7 @@ corresponding stream is closed with @code{close/1} or @code{close/2}.
 Interface to system call @code{bind}, as used for servers: bind socket
 to a port. Port information depends on the domain:
 @table @code
-@item 'AF_UNIX'(+@var{FILENAME})
+@item 'AF_UNIX'(+@var{FILENAME}) (unsupported)
 @item 'AF_FILE'(+@var{FILENAME})
 use file name @var{FILENAME} for UNIX or local sockets.
 

library/Makefile.in

@@ -60,6 +60,7 @@ PROGRAMS= \
 	$(srcdir)/rbtrees.yap \
 	$(srcdir)/regexp.yap \
 	$(srcdir)/rltree.yap \
+	$(srcdir)/sockets.yap \
 	$(srcdir)/splay.yap \
 	$(srcdir)/stringutils.yap \
 	$(srcdir)/system.yap \

library/sockets.yap

@@ -0,0 +1,105 @@
+/** uses SWI code
+
+<module> SICStus compatible socket library
+
+@tbd Our implementation does not support AF_UNIX sockets.
+@TBD Implement socket_select/5
+@see http://www.sics.se/sicstus/docs/3.7.1/html/sicstus_28.html
+*/
+
+
+:- module(yap_sockets,
+	  [ ip_socket/2,		% +Domain, -Socket
+	    ip_socket/4,		% +Domain, +Type, +Protocol, -Socket
+	    socket_close/1,		% +Socket
+	    socket_bind/2,		% +Socket, 'AF_INET'(+Host,+Port)
+	    tcp_socket_connect/3,	% +Socket, 'AF_INET'(+Host,+Port), -Stream
+	    socket_listen/2,		% +Socket, +Length
+	    socket_accept/2,		% +Socket, -Stream
+	    socket_accept/3,		% +Socket, -Client, -Stream
+%	    socket_select/5,		% +TermsSockets, -NewTermsStreams,
+	    				% +TimeOut, +Streams, -ReadStreams
+	    current_host/1,		% ?HostName
+	    hostname_address/2		% ?HostName, ?HostAddress
+	  ]).
+:- use_module(library(socket)).
+:- use_module(library(error)).
+:- use_module(library(apply)).
+
+%socket(+@var{DOMAIN},+@var{TYPE},+@var{PROTOCOL},-@var{SOCKET})
+
+ip_socket(Domain, 'SOCK_DGRAM', Protocol, SOCKET) :-
+    must_be(oneof(['AF_INET']), Domain),
+    must_be(oneof([0]), Protocol),
+    udp_socket(SOCKET),
+    assert(yap_socket(udp, SOCKET)).
+ip_socket(Domain, 'SOCK_STREAM', Protocol, SOCKET)  :-
+    must_be(oneof(['AF_INET']), Domain),
+    must_be(oneof([0]), Protocol),
+    tcp_socket(SOCKET),
+    assert(yap_socket(tcp, SOCKET)).
+
+ip_socket(Domain, SOCK) :-
+    socket(Domain, 'SOCK_STREAM', 0, SOCK).
+
+socket_close(Socket) :-
+    retract(yap_socket(udp, Socket)), !.
+socket_close(Socket) :-
+    retract(yap_socket(tcp, Socket)), !,
+    tcp_close_socket(Socket).
+
+socket_bind(Socket, 'AF_INET'(Host,Port)) :-
+	(   Address = 'AF_INET'(Host, Port)
+	->  true
+	;   type_error(socket_address, Address)
+	),
+	(   var(Host)
+	->  gethostname(Host)
+	;   true			% Warning?
+	),
+	tcp_bind(Socket, Port).
+
+tcp_socket_connect(Socket, Address, StreamPair) :-
+    (   Address = 'AF_INET'(Host, Port)
+    ->  true
+    ;   type_error(socket_address, Address)
+    ),
+    tcp_connect(Socket, Host:Port),
+    tcp_open_socket(Socket, Read, Write),
+    stream_pair(StreamPair, Read, Write).
+
+socket_listen(SOCKET, BACKLOG) :-
+    tcp_listen(SOCKET, BACKLOG).
+
+socket_accept(Socket, Client, StreamPair) :-
+    tcp_accept(Socket, Socket2, Peer),
+    peer_to_client(Peer, Client),
+    tcp_open_socket(Socket2, Read, Write),
+    stream_pair(StreamPair, Read, Write).
+
+socket_buffering(STREAM, _, CUR, NEW) :-
+    stream_property(STREAM, buffer(Prop) ),
+    translate_buffer(Prop, CUR),
+    translate_buffer(NProp, NEW),
+    stream_property(STREAM, buffer(NProp) ).
+
+translate_buffer(false, unbuf).
+translate_buffer(full, fullbuf).
+
+current_host(Host) :-
+    gethostname(Host).
+
+hostname_address(Host, Address) :-
+    nonvar(Host), !,
+    tcp_host_to_address(Host, IP),
+    peer_to_client(IP, Address).
+
+peer_to_client(ip(A,B,C,D), Client) :-
+    Parts = [A,B,C,D],
+    ground(Parts), !,
+    atomic_list_concat(Parts, '.', Client).
+peer_to_client(ip(A,B,C,D), Client) :-
+    atomic_list_concat(Parts, '.', Client),
+    maplist(atom_number, Parts, Numbers),
+    Numbers = [A,B,C,D].
+

pl/yio.yap

@@ -78,6 +78,26 @@
 '$check_boolean'(X,B,T,G) :-
 	'$do_error'(domain_error(B,T),G).
 
+socket(Domain, Sock) :-
+	(
+	 '$undefined'(ip_socket(_,_),yap_sockets)
+	->
+	 load_files(library(sockets), [silent(true),if(not_loaded)])
+	;
+	 true
+	),
+	yap_sockets:ip_socket(Domain, Sock).
+
+socket(Domain, Type, Protocol, Sock) :-
+	(
+	 '$undefined'(ip_socket(_,_),yap_sockets)
+	->
+	 load_files(library(sockets), [silent(true),if(not_loaded)])
+	;
+	 true
+	),
+	yap_sockets:ip_socket(Domain, Type, Protocol, Sock).
+
 open_pipe_streams(Read, Write) :-
 	(
 	 '$undefined'(pipe(_,_),unix)