From cf3cb21fd7760a70d618e92f91d1a2d12f23b6c5 Mon Sep 17 00:00:00 2001
From: Vitor Santos Costa <vsc@dcc.fc.up.pt>
Date: Wed, 4 Aug 2010 21:46:10 +0100
Subject: [PATCH] subsumes_term/2 (from ISO and UD #173).

---
 docs/yap.tex | 10 ++++++++++
 pl/utils.yap |  4 ++++
 2 files changed, 14 insertions(+)

diff --git a/docs/yap.tex b/docs/yap.tex
index f039d3a8e..7fa26b080 100644
--- a/docs/yap.tex
+++ b/docs/yap.tex
@@ -3350,6 +3350,16 @@ is bound to the empty list (nil) or a term with functor '.' and arity 2.
 
 Same as @code{variant/2}, succeeds if @var{Term1} and @var{Term2} are variant terms.
 
+
+@item subsumes_term(?@var{Subsumer}, ?@var{Subsumed})
+@findex  subsumes_term/2
+@syindex subsumes_term/2
+@cnindex subsumes_term/2
+
+Succeed if @var{Submuser} subsumes @var{Subsuned} but does not bind any
+variable in @var{Subsumer}.
+
+
 @end table
 
 @node Predicates on Atoms, Predicates on Characters, Testing Terms, Top
diff --git a/pl/utils.yap b/pl/utils.yap
index 6e47fa905..7ceb01e24 100644
--- a/pl/utils.yap
+++ b/pl/utils.yap
@@ -643,3 +643,7 @@ nb_current(GlobalVariable, Val) :-
 	).
 
 
+subsumes_term(A,B) :-
+	\+ \+ terms:subsumes(A,B).
+
+