/*  rules2.pl plj 2/16/94 */
/*  rules.pl plj 2/21/93 */
/*  plj updated 3/2/93 with exec */
run(STMStart,STMFinal,ProblemNum,Answer) :-
  run_rule(STMStart,STM2,ProblemNum,Answer),run(STM2,STMFinal,ProblemNum,Answer).
run(STM,STM,ProblemNum,[rules,stoped,because,no,more,rules,can,fire,
         probmemnumber,ProblemNum,endingSTM,STM]).

run_rule(STMStart,STMFinal,ProblemNum,Answer) :-
  rule(RuleName,RuleLHS,RuleRHS),
  list_match(RuleLHS,STMStart,STMStart,_),
  write(firing_rule),write(RuleName),nl,
  !,
  fire_rule(RuleRHS,STMStart,STMFinal),
  write(new_stm),write(STMFinal),nl.

fire_rule([],STM,STM).
fire_rule([Command|RestCommands],STMStart,STMFinal) :- 
   do_command(Command,STMStart,STM2),
   fire_rule(RestCommands,STM2,STMFinal).

do_command([add,AddItem],STM,[AddItem|STM]).
do_command([del,DelItem],STMStart,STMFinal) :-
  add_member(DelItem,STMFinal,STMStart).
do_command([exec,ExecName,PatternExec],STM,STM) :- exec(ExecName,PatternExec).
do_command([read,PromptMessage],STM,[ReadItem|STM]) :-
  write(PromptMessage),nl,read(ReadItem).
do_command([print,Message],STM,STM) :-
  write(Message),nl.

list_match([],_,List,List).
list_match([not,Item|RestItems],ListFull,ListIn,ListUnmatched) :-
  not_member(Item,ListFull),
  list_match(RestItems,ListFull,ListIn,ListUnmatched).
list_match([test,[NameTest,ParmTest]|RestItems],ListFull,ListIn,ListUnmatched) :-
  test(NameTest,ParmTest),
  list_match(RestItems,ListFull,ListIn,ListUnmatched).
list_match([Item|RestItems],ListFull,ListIn,ListUnmatched) :-
  add_member(Item,List2,ListIn),
  list_match(RestItems,ListFull,List2,ListUnmatched).

add_member(Item,[],[Item]).
add_member(Item,List,[Item|List]).
add_member(Item,[HeadList|RestList],[HeadList|NewRestList]) :-
  add_member(Item,RestList,NewRestList).
not_member(Item,List) :- member(Item,List),!,fail.
not_member(Item,List).
member(Item,[Item|RestList]).
member(Item,[OtherItem|RestList]) :- member(Item,RestList).


/*-------------------------start rules--------------*/
/*
*/
/* example.rules plj 2/22/93 */
rule(p1,[[put-on,Object,Support]],
        [[del,[put-on,Object,Support]],
         [add,[put-at,Object,[space,on,Support]]]]).
rule(p2,[[put-at,Object,Newplace],not,[grasp,Object]],
        [[del,[put-at,Object,Newplace]],
         [add,[target,Object,Newplace]],
         [add,[grasp,Object]]]).
rule(p3,[[move,Object],[Support,supports,Object]],
        [[del,[move,Object]],
         [del,[Support,supports,Object]]]).
rule(p4,[[move,Object]],
        [[del,[move,Object]],
         [print,[move-hand,Newplace]],
         [print,[ungrasp]]]).
rule(p5,[[grasp,Object],[Object,supports,nothing]],
        [[del,[grasp,Object]],
         [del,[Object,supports,nothing]],
         [add,[move,Object]],
         [print,[move-hand,[top-of,Object]]],
         [print,[grasp,Object]]]).
rule(p6,[[grasp,Object],[Object,supports,Obstruction],
         not,[grasp,Obstruction]],
        [[add,[put-on,Obstruction,floor]]]).
rule(p7,[[grasp,Object],not,[Object,supports,Obstruction]],
        [[read,[what,is,on,Object]]]).
         
tryit :- run([[put-at,table,xyz]],STMFinal,1,Answer),write(Answer),nl.