Calling predicates from source code & backtracking

General
1

Hello.
I’ve encountered some strange behaviour.
I call some predicate from source by using following syntax:

:- my_predicate(parameters).

inside my_predicates uses undo/1 as part of backtrackable assertions. But they are undone immediately after predicate is finished. Using cuts didn’t help me. I assume that prolog engine undoes everything because undo/1 has nothing to do with choicepoints and cuts. It simply cleares of everything that is put in trail. Problem is that my_predicate is supposed to be used in other contexts where undoing asserts are expected, so I can’t just use non-backtrackable version of assert inside it.

Is there a way to manipulate undo records to emulate something like cut for them?
Or I just better use some global flag to supress call to undo/1?

EDIT #1: Another question arised: if undo records are not purged but cuts, does it imply that theese records might accumulate over program working even if by design program should never backtrack past undo/1 calls? Can it possibly lead to memory leaks?

EDIT #2: What is the logic of backtracking after :- or ?- calls in source code?

2

The control structure of the compiler is failure driven. I.e., there is a predicate that on backtracking produces (expanded) Prolog terms and the next step which adds these to the database and fails until we see end_of_file.

I have little clue what problem you are trying to solve, but this route is not going to work.

3

I’am writing program which procedurally generates some model, expressed as set of dynamic facts. In that process program backtracks to find consistent solution, therefore I use backtrackable assertions using undo/1. For testing purposes I sometimes call it’s predicates from REPL or from sources directly. REPL can be switched to recursive mode, but with source-code calls it is not possible as I understand.

As a stopgap measure I switched to another b_assert implementation, using ;/2. For now it works. Then I will do some scaffolding code to work around this issue.