A new bug in my old code?

Help!
1

I’m using: SWI-Prolog version 10.0.2.

I want the code to: retract all dynamic predicates that are not built-in.

But what I’m getting after cleanup each time I consult a file is: ERROR: Domain error: `file_type’ expected, found `prolog’.

My code looks like this:

cleanup :- forall(dynamic_not_built_in(X),retractall(X)).

dynamic_not_built_in(X) :- predicate_property(X,dynamic),
                           \+predicate_property(X,built_in).

Call the above program mwe.pl, consult it and run cleanup. Then consult it again and get the ERROR above. Code like this has never given any problem in versions < 9. From 9 on I get this behaviour. I suspect cleanup now retracts too much, perhaps an essential dynamic predicate which is not a built-in. Any help is highly appreciated! Marc

2

I suspect cleanup now retracts too much,

You can easily check this hypotesis. In cleanup change retractall to writeln, and check whether the result looks reasonable.

3

There is no overlap, so that will not filter as intended:

Welcome to SWI-Prolog (threaded, 64 bits, version 10.0.2)

101 ?- predicate_property(X, dynamic), predicate_property(X, built_in).
false.
4

Good suggestion, see the list below. I would have expected all of these are built-in.

I guess the last one is the culprit.

61 ?- cleanup.
prolog_load_file(_7456,_7458)
portray(_7456)
expand_answer(_7456,_7458)
resource(_7456,_7458)
exception(_7456,_7458,_7460)
term_expansion(_7456,_7458)
goal_expansion(_7456,_7458,_7460,_7462)
term_expansion(_7456,_7458,_7460,_7462)
resource(_7456,_7458,_7460)
file_search_path(_7456,_7458)
goal_expansion(_7456,_7458)
expand_query(_7456,_7458,_7460,_7462)
message_hook(_7456,_7458,_7460)
thread_message_hook(_7456,_7458,_7460)
library_directory(_7456)
prolog_file_type(_7456,_7458)
true.

5

But something must have changed. I seem to remember (but the program is 20y old) that it was necessary to exclude built-in predicates in those days:

´´´Welcome to SWI-Prolog (threaded, 64 bits, version 8.0.3)
SWI-Prolog comes with ABSOLUTELY NO WARRANTY. This is free software.
Please run ?- license. for legal details.

For online help and background, visit http://www.swi-prolog.org
For built-in help, use ?- help(Topic). or ?- apropos(Word).

?- cleanup.
prolog_exception_hook(_7210,_7212,_7214,_7216)
thread_message_hook(_7210,_7212,_7214)
true.

?- [mwe].
true.

´´´BTW why is the mark-up not working on discourse?

All these were built-in in version 8:

?- predicate_property(X,dynamic),predicate_property(X,built_in).
X = prolog_event_hook(_7564) ;
X = file_search_path(_7564, _7566) ;
X = term_expansion(_7564, _7566) ;
X = resource(_7564, _7566, _7568) ;
X = prolog_file_type(_7564, _7566) ;
X = goal_expansion(_7564, _7566) ;
X = goal_expansion(_7564, _7566, _7568, _7570) ;
X = portray(_7564) ;
X = term_expansion(_7564, _7566, _7568, _7570) ;
X = expand_query(_7564, _7566, _7568, _7570) ;
X = expand_answer(_7564, _7566) ;
X = message_hook(_7564, _7566, _7568) ;
X = library_directory(_7564) ;
X = prolog_load_file(_7564, _7566) ;
X = resource(_7564, _7566) ;
X = exception(_7564, _7566, _7568) ;
false.

6

In conclusion: from version 8 to version 10 the number of system-like predicates that are dynamic (but not built-in) increased substantially.

My problem is now: how to discriminate in a robust way between user-defined dynamic predicates and all other dynamic predicates?

7

maybe you can discriminate based on file of origin:

predicate_property(P,dynamic),
predicate_property(P,file(F)),
\+ sub_atom(F,_,_,_,'/swipl/library/'),
\+ sub_atom(F,_,_,_,'/swipl/boot/').

if it has these in the name probably is not a user defined one. Not 100% safe, but may be a stopgap.