implement indexes

.gitignore

@@ -0,0 +1 @@
+data.pl

data.pl

@@ -1,4 +0,0 @@
-task("take over a world",todo).
-task("sleep",done).
-task("finish this",todo).
-task("test task",todo).

todo.pl

@@ -1,26 +1,45 @@
 :- dynamic task/2.
 :- dynamic requires/2.
+:- dynamic idx/2.
 :- discontiguous load/0.
 
-task("take over a world", todo).
-task("sleep", done).
-task("finish this", todo).
-
 all_tasks(L):- findall(X, task(X, _), L).
 all_tasks(L, STATE):- findall(X, task(X, STATE), L).
 
-print_task_list([]).
-print_task_list([H|T]) :- task(H,ISDONE), write(ISDONE),write(': '), write(H),nl, print_task_list(T).
 
-list :- all_tasks(L), print_task_list(L).
+print_task_list([],_).
+print_task_list([H|T],N) :- 
+    M is N+1,
+    retractall(idx(N, _)),
+    asserta(idx(N, H)),
+    write(N),
+    write(". "),
+    task(H,ISDONE), 
+    write(ISDONE),
+    write(': '), 
+    write(H),nl, 
+    print_task_list(T, M).
+
+list_all :- all_tasks(L), print_task_list(L,1).
+list_all :- all_tasks(L), print_task_list(L,1).
+list :- all_tasks(L, todo), print_task_list(L,1).
+list_done :- all_tasks(L, done), print_task_list(L,1).
 
 print_list([]).
 print_list([H|T]) :- write(H),nl, print_list(T).
 
-new(X) :- asserta(task(X, todo)), write("added task "), 
+new(X) :- 
+    asserta(task(X, todo)), 
+    write("added task "), 
     write(X).
-check(X) :- task(X, todo), asserta(task(X, done)), retractall(task(X, todo)), 
+check(X) :- 
-write("marked task "), write(X), write(" as done").
+    task(X, todo), 
+    asserta(task(X, done)), 
+    retractall(task(X, todo)), 
+    write("marked "), 
+    write(X), 
+    write(" as done").
+check(X) :- idx(X, Task), check(Task).
 
 
 save_task(Task, Stream) :-
@@ -45,17 +64,24 @@ save :-
 
 load_task(Stream) :- 
     read(Stream, Task),
-    Task = end_of_file,
+    Task \= end_of_file,
-    close(Stream).
+%    write("reading: "),
+%    write(Task),
+%    nl,
+    asserta(Task),
+    load_task(Stream).
 
 load_task(Stream) :- 
     read(Stream, Task),
-    asserta(Task),
+    Task = end_of_file,
-    load_task(Stream).
+%    write("reading last: "),
+%    write(Task),
+    close(Stream).
+
 load :-
     open('data.pl', read, Stream),
     load_task(Stream).
 
 clear :- retractall(task(_, _)).
 
-consult(data).
+load.