format('~N~n~n'))),!,
 %stack_dump,
 stream_property(S2,file_no(2)),
    with_output_to(S2,
     (format('~N~n~n',[]),
      write_src(G),
      format('~N~n~n'))),!.

:- meta_predicate(rrtrace(0)).
rrtrace(X):- rrtrace(etrace,X).

stack_dump:-  ignore(catch(bt,_,true)). %,ignore(catch(dumpST,_,true)),ignore(catch(bts,_,true)).
ugtrace(error(Why),G):- !, notrace,write_src_uo(Why),stack_dump,write_src_uo(Why),rtrace(G).
ugtrace(Why,G):-  tracing,!,notrace,write_src(Why),rtrace(G).
ugtrace(Why,_):-  is_testing, !, ignore(give_up(Why,5)),throw('$aborted').
ugtrace(_Why,G):-  ggtrace(G),throw('$aborted').
%ugtrace(Why,G):- ggtrace(G).

give_up(Why,_):- is_testing,!,write_src_uo(Why),!, throw(give_up(Why)).
give_up(Why,N):- is_testing,!,write_src_uo(Why),!, halt(N).
give_up(Why,_):- write_src_uo(Why),throw('$aborted').

is_guitracer:- getenv('DISPLAY',_), current_prolog_flag(gui_tracer,true).
:- meta_predicate(rrtrace(1,0)).
rrtrace(P1,X):- never_rrtrace,!,nop((u_dmsg(cant_rrtrace(P1,X)))),!,fail.
rrtrace(P1,G):- is_cgi,!, u_dmsg(arc_html(rrtrace(P1,G))),call(P1,G).
rrtrace(P1,X):- notrace, \+ is_guitracer,!,nortrace, /*arcST, sleep(0.5), trace,*/
   (notrace(\+ current_prolog_flag(gui_tracer,true)) -> call(P1,X); (itrace,call(P1,X))).
%rrtrace(_,X):- is_guitracer,!,notrace,nortrace,ncatch(call(call,ugtrace),_,true),atrace,call(X).
rrtrace(P1,X):- itrace,!, call(P1,X).

:- meta_predicate(arc_wote(0)).
arc_wote(G):- with_pp(ansi,wote(G)).
arcST:- itrace,arc_wote(bts),itrace.
atrace:- arc_wote(bts).
%atrace:- ignore((stream_property(X,file_no(2)), with_output_to(X,dumpST))),!.

:- meta_predicate(odd_failure(0)).
odd_failure(G):- never_rrtrace,!,call(G).
odd_failure(G):- wno_must(G)*->true;fail_odd_failure(G).

:- meta_predicate(fail_odd_failure(0)).
fail_odd_failure(G):- u_dmsg(odd_failure(G)),rtrace(G), fail.
%fail_odd_failure(G):- call(G)*->true;(u_dmsg(odd_failure(G)),fail,rrtrace(G)).


bts:-
 ensure_loaded(library(prolog_stack)),
 prolog_stack:export(prolog_stack:get_prolog_backtrace_lc/3),
 use_module(library(prolog_stack),[print_prolog_backtrace/2,get_prolog_backtrace_lc/3]),
  /*notrace*/(prolog_stack:call(call,get_prolog_backtrace_lc,8000, Stack, [goal_depth(600)])),
  stream_property(S,file_no(1)), prolog_stack:print_prolog_backtrace(S, Stack),
  ignore((fail, current_output(Out), \+ stream_property(Out,file_no(1)), print_prolog_backtrace(Out, Stack))),!.

my_assertion(G):- my_assertion(call(G),G).

my_assertion(_,G):- call(G),!.
my_assertion(Why,G):- u_dmsg(my_assertion(Why,G)),writeq(Why=goal(G)),nl,!,ibreak.

must_be_free(Free):- plain_var(Free),!.
must_be_free(Free):- \+ nonvar_or_ci(Free),!.
must_be_free(Nonfree):- arcST,u_dmsg(must_be_free(Nonfree)),
  ignore((attvar(Nonfree),get_attrs(Nonfree,ATTS),pp(ATTS))),ibreak,fail.

must_be_nonvar(Nonvar):- nonvar_or_ci(Nonvar),!.
must_be_nonvar(IsVar):- arcST,u_dmsg(must_be_nonvar(IsVar)),ibreak,fail.