/* $Id: tty.pl,v 1.5 2002/02/01 16:49:11 jan Exp $ Part of SWI-Prolog Author: Jan Wielemaker E-mail: jan@swi.psy.uva.nl WWW: http://www.swi-prolog.org Copyright (C): 1985-2002, University of Amsterdam This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA As a special exception, if you link this library with other files, compiled with a Free Software compiler, to produce an executable, this library does not by itself cause the resulting executable to be covered by the GNU General Public License. This exception does not however invalidate any other reasons why the executable file might be covered by the GNU General Public License. */ :- module(tty, [ tty_clear/0 , tty_flash/0 , menu/3 ]). /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - TERMINAL OPERATIONS This library package defines some common operations on terminals. It is based on the Unix termcap facility to perform terminal independant I/O on video displays. The package consists of three sections: 1) Predicates to perform simple operations on terminals 2) Extenstions to format/2 to include cursor position and clearing sections of the screen. 3) A generic predicate to build simple menus. BUGS The stream information on the terminal related streams is not maintained by these predicates. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ % tty_clear/0 % Clear the display. tty_clear :- string_action(cl). % tty_flash/0 % Give visual signal if possible, otherwise beep. tty_flash :- tty_get_capability(vb, string, Vb), !, tty_put(Vb, 1). tty_flash :- put(7). % string_action(+Name) % Send string from the termcap library with specified name. string_action(Name) :- tty_get_capability(Name, string, String), tty_put(String, 1). /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - FORMAT The functions below add some extras to the format facilities. This to simplify screen management. It adds ~T to the set of format characters. The argument to ~T is a (list of) tty control commands. The ~l command is defined to clear to the end of the line before generating a newline. Example: ?- format('~T~3l', home), format(' 1) Hello World~l'), format(' 2) Exit~2l'), format(' Your choice? ~T', [clear_display, flush]), get_single_char(X). - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ :- format_predicate('T', tty_action(_Arg, _What)). :- format_predicate('l', tty_nl(_Args)). tty_action(_, What) :- tty_action(What). tty_action([]) :- !. tty_action([A|B]) :- !, tty_action(A), tty_action(B). tty_action(goto(X,Y)) :- !, tty_goto(X, Y). tty_action(home) :- !, tty_goto(0, 0). tty_action(flush) :- !, ttyflush. tty_action(center(Text)) :- !, tty_size(W, _), format('~t~a~t~*|', [Text, W]). tty_action(back(N)) :- !, between(1, N, _), put(8), fail ; true. tty_action(Long) :- abbreviation(Long, Short), !, string_action(Short). tty_action(Short) :- string_action(Short). abbreviation(clear, cl). % clear and home abbreviation(clear_line, ce). % clear-to-end-of-line abbreviation(clear_display, cd). % clear-to-end-of-display tty_nl(default) :- !, tty_nl(1). tty_nl(N) :- tty_get_capability(ce, string, Ce), between(1, N, _), tty_put(Ce, 1), nl, fail ; true. /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - MENU The package below is a simple package to show (short) menus. The entry point is the predicate menu/3, which is described below. menu(+Title, +Options, -Choice) Show a menu. The display is cleared, the title is centered at the top, the options are displayed and finally the user actions are parsed and the user's choice is returned. The screen looks like this: -------------------------------------------- | | | Title | | | | 1) Option One | | 2) Option Two | | 3) Quit | | | | Your Choice? * | | | The user selects an item by pressing the number of the item, or the first letter of the option. If more then one option match, the common prefix of the matching options is given and the user is expected to type the next character. On illegal input the screen is flashed (or a beep is given if the terminal can't flash the screen). Text fields (the title and option texts) are either plain atoms or terms Fmt/Args. In the latter case the argument is transformed into an atom using sformat/3. The specification of an option is a term PrologName:UserName. PrologName is an atom, which is returned as choice if the user selects this menu item. UserName is processed as a text field (see above) and displayed. The entries are numbered automatically. The example above could be defined as: get_action(Choice) :- menu('Title', [ option_1 : 'Option One' , option_2 : 'Option Two' , quit : 'Quit' ], Choice). - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ menu(Title, List, Choice) :- show_title(Title), build_menu(List), get_answer(List, Choice). show_title(Title) :- to_text(Title, T), format('~T~l~T~2l', [clear, center(T)]). build_menu(List) :- build_menu(List, 1), format('~2n Your choice? ~T', clear_display). build_menu([], _). build_menu([_:H|T], N) :- to_text(H, TH), format('~t~d~6|) ~a~l', [N, TH]), succ(N, NN), build_menu(T, NN). to_text(Fmt/Args, Text) :- !, sformat(Text, Fmt, Args). to_text(Text, Text). get_answer(List, Choice) :- flag('$menu_feedback', _, 0), get_answer(List, [], Choice). get_answer(List, Prefix, Choice) :- get_single_char(A), process_answer(A, List, Prefix, NewPrefix, Ch, Ok), ( Ok == yes -> Ch = Choice ; get_answer(List, NewPrefix, Choice) ). process_answer(127, _, _, [], _, no) :- !, feedback(''). process_answer(D, List, _, _, Choice, yes) :- code_type(D, digit), name(N, [D]), nth1(N, List, Choice:Name), !, feedback(Name). process_answer(D, _, _, [], _, no) :- code_type(D, digit), feedback(''), tty_flash. process_answer(C, List, Prefix, NewPrefix, Choice, Ok) :- append(Prefix, [C], NPrefix), matching(List, NPrefix, Matching), ( Matching == [] -> tty_flash, NewPrefix = Prefix, Ok = no ; Matching = [Choice:Name] -> Ok = yes, feedback(Name) ; common_prefix(Matching, NewPrefix), feedback(NewPrefix), Ok = no ). matching([], _, []). matching([H|T], Prefix, [H|R]) :- prefix(Prefix, H), !, matching(T, Prefix, R). matching([_|T], Prefix, R) :- matching(T, Prefix, R). prefix(Prefix, _:Name) :- name(Name, Chars), common_prefix_strings(Prefix, Chars, Prefix), !. common_prefix([_:Name|T], Prefix) :- name(Name, Chars), common_prefix(T, Chars, Prefix). common_prefix([], Prefix, Prefix). common_prefix([_:Name|T], Sofar, Prefix) :- name(Name, Chars), common_prefix_strings(Chars, Sofar, NewSofar), common_prefix(T, NewSofar, Prefix). common_prefix_strings([H1|T1], [H2|T2], [H1|R]) :- code_type(Lower, to_lower(H1)), code_type(Lower, to_lower(H2)), !, common_prefix_strings(T1, T2, R). common_prefix_strings(_, _, []). feedback(Text) :- atomic(Text), !, atom_length(Text, New), flag('$menu_feedback', Old, New), format('~T~a~T', [back(Old), Text, clear_line]). feedback(Text) :- length(Text, New), flag('$menu_feedback', Old, New), format('~T~s~T', [back(Old), Text, clear_line]).