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| author | Peter Mikkelsen <peter@pmikkelsen.com> | 2021-07-09 20:09:22 +0000 |
|---|---|---|
| committer | Peter Mikkelsen <peter@pmikkelsen.com> | 2021-07-09 20:09:22 +0000 |
| commit | a37ae2f0170499be1a95031d24ff86aac5cf46f1 (patch) | |
| tree | fcd3a769a460a5b8a5b54c53cd70ed5d2834a73a /stdlib.pl | |
| parent | d2a0828140c31514c514b8e4fb9a4d52c389d8fe (diff) | |
Add asserta/1, assertz/1, retract/1, abolish/1 (and retract_one/1, which is retract/1 but doesn't backtrack)
Diffstat (limited to 'stdlib.pl')
| -rw-r--r-- | stdlib.pl | 12 |
1 files changed, 9 insertions, 3 deletions
@@ -10,8 +10,7 @@ once(Goal) :- repeat :- true ; repeat. -% Control structures. -true. +% Control structures. If -> Then :- If, !, Then. @@ -150,7 +149,7 @@ E1 > E2 :- E2 < E1. -% Clause retrieval and information +% Clause retrieval and information and removal clause(Head, Body) :- clause(Head, Body, Clauses), @@ -160,6 +159,13 @@ current_predicate(PI) :- current_predicate(PI, Predicates), member(PI, Predicates). +retract(Clause) :- + copy_term(Clause, ClauseCopy), + retract_one(ClauseCopy), + ( Clause = ClauseCopy + ; retract(Clause) + ). + % Basic list predicates member(X, [X|_]). member(X, [_|Tail]) :- |