From dff53b4e68333ce676f2ce1c970286921ca22e53 Mon Sep 17 00:00:00 2001
From: Tibo De Peuter <tibo.depeuter@ugent.be>
Date: Tue, 6 May 2025 21:10:44 +0200
Subject: [PATCH] fix: Groene vinkjes

---
 src/prolog/ast/logic/Clause.kt | 8 +++++---
 tests/e2e/Examples.kt          | 4 ++--
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/src/prolog/ast/logic/Clause.kt b/src/prolog/ast/logic/Clause.kt
index 9955539..1080a9f 100644
--- a/src/prolog/ast/logic/Clause.kt
+++ b/src/prolog/ast/logic/Clause.kt
@@ -44,14 +44,16 @@ abstract class Clause(var head: Head, var body: Body) : Term, Resolvent {
                     bodyAnswer.fold(
                         onSuccess = { bodySubs ->
                             // If the body can be proven, yield the (combined) substitutions
-                            var result = goalToHeadSubs.mapValues { applySubstitution(it.value, bodySubs) }
-                            yield(Result.success(result))
+                            val goalToHeadResult = goalToHeadSubs.mapValues { applySubstitution(it.value, bodySubs) }
+                            val headResult = headToGoalSubs.filterKeys { key -> goalToHeadSubs.any { occurs(key as Variable, it.value) } }
+                            yield(Result.success(goalToHeadResult + headResult))
                         },
                         onFailure = { error ->
                             if (error is AppliedCut) {
                                 // Find single solution and return immediately
                                 if (error.subs != null) {
-                                    yield(Result.failure(AppliedCut(headAndGoalSubs + error.subs)))
+                                    var result = goalToHeadSubs.mapValues { applySubstitution(it.value, error.subs) }
+                                    yield(Result.failure(AppliedCut(result)))
                                 } else {
                                     yield(Result.failure(AppliedCut()))
                                 }
diff --git a/tests/e2e/Examples.kt b/tests/e2e/Examples.kt
index f93fc35..bafef47 100644
--- a/tests/e2e/Examples.kt
+++ b/tests/e2e/Examples.kt
@@ -27,7 +27,7 @@ class Examples {
 
     @Test
     fun debugHelper() {
-        loader.load("examples/basics/backtracking.pl")
+        loader.load("examples/basics/arithmetics.pl")
     }
 
     @ParameterizedTest
@@ -45,7 +45,7 @@ class Examples {
     }
 
     fun basics() = listOf(
-        Arguments.of("arithmetics.pl", "gimli is a level 4 fighter with 35 hitpoints.\nlegolas is a level 5 ranger with 30 hitpoints.\ngandalf is a level 10 wizard with 25 hitpoints.\nfrodo is a level 2 rogue with 20 hitpoints.\nlegolas threw gimli, and gimli took 5 damage.\ngimli is a level 4 fighter with 30 hitpoints.\ngandalf casts aid.\ngimli is a level 4 fighter with 35 hitpoints.\nlegolas leveled up.\nlegolas is a level 6 ranger with 30 hitpoints"),
+        Arguments.of("arithmetics.pl", "gimli is a level 4 fighter with 35 hitpoints.\nlegolas is a level 5 ranger with 30 hitpoints.\ngandalf is a level 10 wizard with 25 hitpoints.\nfrodo is a level 2 rogue with 20 hitpoints.\nlegolas threw gimli, and gimli took 5 damage.\ngimli is a level 4 fighter with 30 hitpoints.\ngandalf casts aid.\ngimli is a level 4 fighter with 35 hitpoints.\nlegolas leveled up.\nlegolas is a level 6 ranger with 30 hitpoints.\n"),
         Arguments.of("backtracking.pl", "0\ns(0)\ns(s(0))\ns(s(s(0)))\n"),
         Arguments.of("cut.pl", "0\n"),
         Arguments.of("disjunction.pl", "Alice likes Italian food.\nBob likes Italian food.\n"),