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%% File         : MULTI_EVAL
%% Created by   : Joakim Eriksson & Niclas Finne
%% Created date : 01-12-4
%%
%% $Author: joakime $
%% $Date: 2001/12/18 20:20:15 $
%% $Revision: 1.2 $
%%
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%%
%% Description:
%%
%% Methods:
%%

:- module(logic_jeval, [start/0,stop/0,alt/0]).
:- use_module('../../jeval/jeval_server', []).
:- use_module('../../jeval/jeval', []).
:- use_module('../../http/http_server', []).
:- use_module('../../html/html', []).

:- dynamic monitor/4.

:- jeval_server:register_applet(eval, logic_jeval).%% applet or application...
:- http_server:register_page('index.html', logic_jeval).
:- http_server:set_default_port(P).

http_request(_HttpReq, HttpRes) :-
    html:page_start(HttpRes, "Logic Monitor Jeval Example"),
    html:heading1(HttpRes, "Logic Monitor Jeval Example"),
    html:send(HttpRes, 'Enter expressions to monitor<br>',[]),
    jeval_server:generate_applet(HttpRes, eval, "width=400 height=200"),
    html:page_end(HttpRes).

client_connected(_Host, User) :-
    jeval:jeval(User, '\c
	       jevalApplet.setLayout(new GridLayout(0,2));\c
	       expr = new TextField[5];
	       result = new Label[5];
	       for (int i=0; i < 5; i++) {\c
	          expr[i] = new TextField("");\c
	          jevalApplet.add(expr[i]);\c
	          result[i] = new Label("Result:");\c
	          jevalApplet.add(result[i]);\c
	       }
	       button = new Button("Update Monitors!");\c
	       jevalApplet.add(button);\c
	       jeval.addActionListener("button");\c
	       jevalApplet.validate();\c
	       jevalApplet.repaint();').

client_disconnected(_User).

client_event(action_event(_, _, _), User) :-
    set_monitors(4, User).

client_result(N, ExpAtom, User) :-
    retractall(monitor(N, _, _, User)),
    get_term(ExpAtom, Expr, Vars), !,
    assert(monitor(N, Expr, Vars, User)),
    call_robust(Expr, Vars, Result),
    jeval:jeval(User, 'result[' + N + '].setText("Result: ' + Result + '")').
client_result(_N, '', _User) :- !.
client_result(N, _ExpAtom, User) :-
    jeval:jeval(User, 'result[' + N + '].setText("Result: syntax error")').

resume(_) :-
    monitor(N, Expr, Vars, User), 
    call_robust(Expr, Vars, Result),
    jeval:jeval(User, 'result[' + N + '].setText("Result: ' + Result + '")'),
    fail.
resume(_).

set_monitors(-1, _) :- !.
set_monitors(N, User) :-
    jeval:jeval(User, N, 'expr[' + N + '].getText().trim()'),
    NextN is N - 1,
    set_monitors(NextN, User).

call_robust(Term, Vars, Result) :-
    catch(charsio:with_output_to_chars(Term, Str), _Error, fail), !,
    Result = Str + ' ' + D,
    print_result(Vars, D).
call_robust(_Term, _Vars, failed).

print_result([], []).
print_result([Name=Var | Rest], Name + ' = ' + Var + ' ' + Stream) :-
    print_result(Rest, Stream).

get_term(Result, Term, Vars) :-
    charsio:atom_to_chars(Result, R_S, "."),
    charsio:open_chars_stream(R_S, DataStream),
    catch(read_term(DataStream, Term, [variable_names(Vars)]), _Error,
	  (close(DataStream),fail)),
    close(DataStream).

start :-
    server:init,
    http_server:get_url(URL),
    format('Please browse to ~s~n', [URL]),
    server:new_thread(tick, logic_jeval),
    server:run.