603 lines
14 KiB
Prolog
603 lines
14 KiB
Prolog
/*************************************************************************
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* *
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* YAP Prolog *
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* *
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* Yap Prolog was developed at NCCUP - Universidade do Porto *
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* *
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* Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-1997 *
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* *
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**************************************************************************
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* *
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* File: yio.yap *
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* Last rev: *
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* mods: *
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* comments: Input output predicates *
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* *
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*************************************************************************/
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/** @defgroup InputOutput Input/Output Predicates
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@ingroup YAPBuiltins
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@{
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Some of the Input/Output predicates described below will in certain conditions
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provide error messages and abort only if the file_errors flag is set.
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If this flag is cleared the same predicates will just fail. Details on
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setting and clearing this flag are given under 7.7.
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*/
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:- system_module( '$_yio', [at_end_of_line/0,
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at_end_of_line/1,
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consult_depth/1,
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current_char_conversion/2,
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current_line_number/1,
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current_line_number/2,
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current_stream/3,
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display/1,
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display/2,
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exists/1,
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fileerrors/0,
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format/1,
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nofileerrors/0,
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open_pipe_streams/2,
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prolog_file_name/2,
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read/1,
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read/2,
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sformat/3,
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socket/2,
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socket/4,
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socket_connect/3,
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stream_position/2,
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stream_position/3,
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stream_position_data/3,
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ttyget/1,
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ttyget0/1,
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ttynl/0,
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ttyput/1,
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ttyskip/1,
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write_depth/2,
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writeln/1], ['$default_expand'/1,
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'$extend_file_search_path'/1,
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'$set_default_expand'/1]).
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:- use_system_module( '$_boot', ['$system_catch'/4]).
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:- use_system_module( '$_errors', ['$do_error'/2]).
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/* stream predicates */
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/* check whether a list of options is valid */
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'$check_io_opts'(V,G) :- var(V), !,
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'$do_error'(instantiation_error,G).
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'$check_io_opts'([],_) :- !.
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'$check_io_opts'([H|_],G) :- var(H), !,
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'$do_error'(instantiation_error,G).
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'$check_io_opts'([Opt|T],G) :- !,
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'$check_opt'(G,Opt,G),
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'$check_io_opts'(T,G).
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'$check_io_opts'(T,G) :-
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'$do_error'(type_error(list,T),G).
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'$check_opt'(read_term(_,_),Opt,G) :-
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'$check_opt_read'(Opt, G).
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'$check_opt'(stream_property(_,_),Opt,G) :-
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'$check_opt_sp'(Opt, G).
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'$check_opt_read'(variables(_), _) :- !.
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'$check_opt_read'(variable_names(_), _) :- !.
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'$check_opt_read'(singletons(_), _) :- !.
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'$check_opt_read'(syntax_errors(T), G) :- !,
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'$check_read_syntax_errors_arg'(T, G).
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'$check_opt_read'(term_position(_), _) :- !.
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'$check_opt_read'(term_position(_), _) :- !.
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'$check_opt_read'(comments(_), _) :- !.
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'$check_opt_read'(module(_), _) :- !.
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'$check_opt_read'(A, G) :-
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'$do_error'(domain_error(read_option,A),G).
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'$check_opt_sp'(file_name(_), _) :- !.
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'$check_opt_sp'(mode(_), _) :- !.
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'$check_opt_sp'(input, _) :- !.
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'$check_opt_sp'(output, _) :- !.
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'$check_opt_sp'(alias(_), _) :- !.
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'$check_opt_sp'(position(_), _) :- !.
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'$check_opt_sp'(end_of_stream(_), _) :- !.
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'$check_opt_sp'(eof_action(_), _) :- !.
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'$check_opt_sp'(reposition(_), _) :- !.
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'$check_opt_sp'(type(_), _) :- !.
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'$check_opt_sp'(bom(_), _) :- !.
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'$check_opt_sp'(encoding(_), _) :- !.
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'$check_opt_sp'(representation_errors(_), _) :- !.
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'$check_opt_sp'(A, G) :-
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'$do_error'(domain_error(stream_property,A),G).
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'$check_read_syntax_errors_arg'(X, G) :- var(X), !,
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'$do_error'(instantiation_error,G).
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'$check_read_syntax_errors_arg'(dec10,_) :- !.
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'$check_read_syntax_errors_arg'(fail,_) :- !.
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'$check_read_syntax_errors_arg'(error,_) :- !.
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'$check_read_syntax_errors_arg'(quiet,_) :- !.
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'$check_read_syntax_errors_arg'(X,G) :-
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'$do_error'(domain_error(read_option,syntax_errors(X)),G).
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'$check_boolean'(X, _, _, G) :- var(X), !,
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'$do_error'(instantiation_error,G).
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'$check_boolean'(true,_,_,_) :- !.
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'$check_boolean'(false,_,_,_) :- !.
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'$check_boolean'(X,B,T,G) :-
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'$do_error'(domain_error(B,T),G).
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/** @defgroup IO_Sockets YAP Old Style Socket and Pipe Interface
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@ingroup InputOutput
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@{
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Autoload the socket/pipe library
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*/
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/** @pred socket(+ _DOMAIN_,- _SOCKET_)
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Call socket/4 with _TYPE_ bound to `SOCK_STREAM'` and
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_PROTOCOL_ bound to `0`.
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*/
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socket(Domain, Sock) :-
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(
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'$undefined'(ip_socket(_,_),yap_sockets)
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->
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load_files(library(sockets), [silent(true),if(not_loaded)])
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;
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true
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),
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yap_sockets:ip_socket(Domain, Sock).
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/** @pred socket(+ _DOMAIN_,+ _TYPE_,+ _PROTOCOL_,- _SOCKET_)
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Corresponds to the BSD system call `socket`. Create a socket for
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domain _DOMAIN_ of type _TYPE_ and protocol
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_PROTOCOL_. Both _DOMAIN_ and _TYPE_ should be atoms,
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whereas _PROTOCOL_ must be an integer.
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The new socket object is
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accessible through a descriptor bound to the variable _SOCKET_.
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The current implementation of YAP accepts socket
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domains `AF_INET` and `AF_UNIX`.
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Socket types depend on the
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underlying operating system, but at least the following types are
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supported: `SOCK_STREAM'` and `SOCK_DGRAM'` (untested in 6.3).
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*/
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socket(Domain, Type, Protocol, Sock) :-
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(
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'$undefined'(ip_socket(_,_),yap_sockets)
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->
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load_files(library(sockets), [silent(true),if(not_loaded)])
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;
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true
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),
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yap_sockets:ip_socket(Domain, Type, Protocol, Sock).
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/** @pred socket_connect(+ _SOCKET_, + _PORT_, - _STREAM_)
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Interface to system call `connect`, used for clients: connect
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socket _SOCKET_ to _PORT_. The connection results in the
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read/write stream _STREAM_.
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Port information depends on the domain:
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+ 'AF_UNIX'(+ _FILENAME_)
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+ 'AF_FILE'(+ _FILENAME_)
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connect to socket at file _FILENAME_.
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+ 'AF_INET'(+ _HOST_,+ _PORT_)
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Connect to socket at host _HOST_ and port _PORT_.
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*/
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socket_connect(Sock, Host, Read) :-
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(
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'$undefined'(ip_socket(_,_),yap_sockets)
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->
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load_files(library(sockets), [silent(true),if(not_loaded)])
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;
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true
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),
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yap_sockets:ip_socket(Domain, Type, Protocol, Sock).
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/** @pred open_pipe_streams(Read, Write)
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Autoload old pipe access interface
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*/
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open_pipe_streams(Read, Write) :-
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(
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'$undefined'(pipe(_,_),unix)
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->
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load_files(library(unix), [silent(true),if(not_loaded)])
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;
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true
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),
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unix:pipe(Read, Write),
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yap_flag(encoding, X),
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set_stream(Read, encoding(X) ),
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set_stream(Write, encoding(X) ).
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%%! @}
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/** @pred fileerrors
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Switches on the file_errors flag so that in certain error conditions
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Input/Output predicates will produce an appropriated message and abort.
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*/
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fileerrors :- '$swi_set_prolog_flag'(fileerrors, true).
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/** @pred nofileerrors
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Switches off the file_errors flag, so that the predicates see/1,
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tell/1, open/3 and close/1 just fail, instead of producing
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an error message and aborting whenever the specified file cannot be
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opened or closed.
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*/
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nofileerrors :- '$swi_set_prolog_flag'(fileerrors, false).
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/** @pred exists(+ _F_)
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Checks if file _F_ exists in the current directory.
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*/
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exists(F) :-
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absolute_file_name(F, _, [file_errors(fail),access(exist),expand(true)]).
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%%! @addtogroup ReadTerm
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% @{
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/* Term IO */
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/** @pred read(- _T_) is iso
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Reads the next term from the current input stream, and unifies it with
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_T_. The term must be followed by a dot (`.`) and any blank-character
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as previously defined. The syntax of the term must match the current
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declarations for operators (see op). If the end-of-stream is reached,
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_T_ is unified with the atom `end_of_file`. Further reads from of
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the same stream may cause an error failure (see open/3).
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*/
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read(T) :-
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read_term(T, []).
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/** @pred read(+ _S_,- _T_) is iso
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Reads term _T_ from the stream _S_ instead of from the current input
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stream.
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*/
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read(Stream,T) :-
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read_term(Stream, T, []).
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%%! @}
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%%! @addtogroup Write
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% @{
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/* meaning of flags for '$write' is
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1 quote illegal atoms
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2 ignore operator declarations
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4 output '$VAR'(N) terms as A, B, C, ...
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8 use portray(_)
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flags are defined in yapio.h
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*/
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/** @pred display(+ _T_)
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Displays term _T_ on the current output stream. All Prolog terms are
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written in standard parenthesized prefix notation.
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*/
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display(T) :-
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current_output(Out),
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write_term(Out, T, [ignore_ops(true)]).
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/** @pred display(+ _S_, _T_)
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Like display/1, but using stream _S_ to display the term.
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*/
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display(Stream, T) :-
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write_term(Term, T, [ignore_ops(true)]).
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/** @pred writeln( _T_) is iso
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Same as write/1 followed by nl/0.
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*/
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writeln(T) :-
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write(T),
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nl.
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/* interface to user portray */
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'$portray'(T) :-
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\+ '$undefined'(portray(_),user),
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'$system_catch'(call(portray(T)),user,Error,user:'$Error'(Error)), !,
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set_value('$portray',true), fail.
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'$portray'(_) :- set_value('$portray',false), fail.
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%%! @}
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%%! @addtogroup Format
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% @{
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/** @pred format(+ _T_)
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Print formatted output to the current output stream.
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*/
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format(T) :-
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format(T, []).
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%%! @}
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%%! @addtogroup CharsIO
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% @{
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/* character I/O */
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/** @pred ttyget(- _C_)
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The same as `get(C)`, but from stream user_input.
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*/
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ttyget(N) :- get(user_input,N).
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/** @pred ttyget0(- _C_)
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The same as `get0(C)`, but from stream user_input.
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*/
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ttyget0(N) :- get0(user_input,N).
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/** @pred ttyskip(- _C_)
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Like skip/1, but always using stream user_input.
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stream.
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*/
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ttyskip(N) :- N1 is N, '$skip'(user_input,N1).
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/** @pred ttyput(+ _N_)
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As `put(N)` but always to user_output.
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*/
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ttyput(N) :- N1 is N, put(user_output,N1).
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/** @pred ttynl
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Outputs a new line to stream user_output.
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*/
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ttynl :- nl(user_output).
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%%! @}
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%%! @addtogroup StreamM
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% @{
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/** @pred current_line_number(- _LineNumber_)
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Unify _LineNumber_ with the line number for the current output stream.
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*/
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current_line_number(N) :-
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current_input(Stream),
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line_count(Stream, N).
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/** @pred current_line_number(+ _Stream_,- _LineNumber_)
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Unify _LineNumber_ with the line number for _Stream_.
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*/
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current_line_number(Stream,N) :-
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line_count(Stream, N).
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/** @pred stream_position(+ _Stream_,- _StreamPosition_)
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Unify _StreamPosition_ with the packaged information of position on
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current stream _Stream_. Use stream_position_data/3 to
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retrieve information on character or line count.
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*/
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stream_position(Stream, Position) :-
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stream_property(Stream, position(Position)).
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/** @pred stream_position(+ _Stream_,- _StreamPosition_, +_NewPosition_)
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Unify _StreamPosition_ with the packaged information of position on
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current stream _Stream_ an then moves to position _NewPosition_.
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*/
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stream_position(Stream, Position, NewPosition) :-
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stream_property(Stream, position(Position)),
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set_stream_position(Stream, NewPosition).
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/** @pred at_end_of_line
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Tests whether the next character in the current input stream is a line break character.
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*/
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at_end_of_line :-
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current_input(S),
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at_end_of_line(S).
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/** @pred at_end_of_line( +Stream )
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Tests whether the next character in the stream is a line break character.
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*/
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at_end_of_line(S) :-
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stream_property(S, end_of_stream(past)), !.
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at_end_of_line(S) :-
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peek_code(S,N), ( N = 10 -> true ; N = -1).
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/** @pred current_char_conversion(? _IN_,? _OUT_) is iso
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If _IN_ is unbound give all current character
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translations. Otherwise, give the translation for _IN_, if one
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exists.
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*/
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current_char_conversion(X,Y) :-
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var(X), !,
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'$all_char_conversions'(List),
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'$fetch_char_conversion'(List,X,Y).
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current_char_conversion(X,Y) :-
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'$current_char_conversion'(X,Y).
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'$fetch_char_conversion'([X,Y|_],X,Y).
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'$fetch_char_conversion'([_,_|List],X,Y) :-
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'$fetch_char_conversion'(List,X,Y).
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/** @pred current_stream( _F_, _M_, _S_)
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Defines the relation: The stream _S_ is opened on the file _F_
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in mode _M_. It might be used to obtain all open streams (by
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backtracking) or to access the stream for a file _F_ in mode
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_M_, or to find properties for a stream _S_. Notice that some
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streams might not be associated to a file: in this case YAP tries to
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return the file number. If that is not available, YAP unifies _F_
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with _S_.
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*/
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current_stream(File, Mode, Stream) :-
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stream_property(Stream, mode(Mode)),
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'$stream_name'(Stream, File).
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'$stream_name'(Stream, File) :-
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stream_property(Stream, file_name(File)), !.
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'$stream_name'(Stream, file_no(File)) :-
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stream_property(Stream, file_no(File)), !.
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'$stream_name'(Stream, Stream).
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'$extend_file_search_path'(P) :-
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atom_codes(P,S),
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'$env_separator'(ES),
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'$split_for_path'(S,0'=,ES,Paths), %'
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'$add_file_search_paths'(Paths).
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'$split_for_path'([], _, _, []).
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'$split_for_path'(S, S1, S2, [A1=A2|R]) :-
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'$fetch_first_path'(S, S1, A1, SR1),
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'$fetch_second_path'(SR1, S2, A2, SR),
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'$split_for_path'(SR, S1, S2, R) .
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'$fetch_first_path'([S1|SR],S1,[],SR) :- !.
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'$fetch_first_path'([C|S],S1,[C|F],SR) :-
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'$fetch_first_path'(S,S1,F,SR).
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'$fetch_second_path'([],_,[],[]).
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'$fetch_second_path'([S1|SR],S1,[],SR) :- !.
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'$fetch_second_path'([C|S],S1,[C|A2],SR) :-
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'$fetch_second_path'(S,S1,A2,SR).
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'$add_file_search_paths'([]).
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'$add_file_search_paths'([NS=DS|Paths]) :-
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atom_codes(N,NS),
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atom_codes(D,DS),
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assert(user:file_search_path(N,D)),
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'$add_file_search_paths'(Paths).
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'$format@'(Goal,Out) :-
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with_output_to(codes(Out), Goal).
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sformat(String, Form, Args) :-
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format(codes(String, []), Form, Args).
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%% stream_position_data(?Field, +Pos, ?Date)
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%
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% Extract values from stream position objects. '$stream_position' is
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% of the format '$stream_position'(Byte, Char, Line, LinePos)
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/** @pred stream_position_data(+ _Field_,+ _StreamPosition_,- _Info_)
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Given the packaged stream position term _StreamPosition_, unify
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_Info_ with _Field_ `line_count`, `byte_count`, or
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`char_count`.
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*/
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stream_position_data(Prop, Term, Value) :-
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nonvar(Prop), !,
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( '$stream_position_field'(Prop, Pos)
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-> arg(Pos, Term, Value)
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; throw(error(domain_error(stream_position_data, Prop)))
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).
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stream_position_data(Prop, Term, Value) :-
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'$stream_position_field'(Prop, Pos),
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arg(Pos, Term, Value).
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'$stream_position_field'(char_count, 1).
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'$stream_position_field'(line_count, 2).
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'$stream_position_field'(line_position, 3).
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'$stream_position_field'(byte_count, 4).
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'$default_expand'(Expand) :-
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get_value('$open_expands_filename',Expand).
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'$set_default_expand'(true) :- !,
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set_value('$open_expands_filename',true).
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'$set_default_expand'(false) :- !,
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set_value('$open_expands_filename',false).
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'$set_default_expand'(V) :- !,
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'$do_error'(domain_error(flag_value,V),yap_flag(open_expands_file_name,X)).
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%%! @}
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'$codes_to_chars'(String0, String, String0) :- String0 == String, !.
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'$codes_to_chars'(String0, [Code|String], [Char|Chars]) :-
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atom_codes(Char, [Code]),
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'$codes_to_chars'(String0, String, Chars).
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/**
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@}
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*/
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