2 files changed, 78 insertions, 1 deletions

diff --git a/org.eclipse.viatra.solver.language.parent/org.eclipse.viatra.solver.language/src/main/java/org/eclipse/viatra/solver/language/ProblemUtil.java b/org.eclipse.viatra.solver.language.parent/org.eclipse.viatra.solver.language/src/main/java/org/eclipse/viatra/solver/language/ProblemUtil.java
index 0151e0c0..3e7d515f 100644
--- a/org.eclipse.viatra.solver.language.parent/org.eclipse.viatra.solver.language/src/main/java/org/eclipse/viatra/solver/language/ProblemUtil.java
+++ b/org.eclipse.viatra.solver.language.parent/org.eclipse.viatra.solver.language/src/main/java/org/eclipse/viatra/solver/language/ProblemUtil.java
@@ -1,17 +1,37 @@
 package org.eclipse.viatra.solver.language;
 
+import java.util.ArrayDeque;
+import java.util.Collection;
+import java.util.Deque;
+import java.util.HashSet;
+import java.util.Optional;
+import java.util.Set;
+
+import org.eclipse.emf.ecore.EObject;
+import org.eclipse.emf.ecore.resource.Resource;
+import org.eclipse.viatra.solver.language.model.problem.ClassDeclaration;
 import org.eclipse.viatra.solver.language.model.problem.Node;
+import org.eclipse.viatra.solver.language.model.problem.Problem;
 import org.eclipse.viatra.solver.language.model.problem.ProblemPackage;
+import org.eclipse.viatra.solver.language.model.problem.ReferenceDeclaration;
 import org.eclipse.viatra.solver.language.model.problem.Variable;
+import org.eclipse.viatra.solver.language.scoping.ProblemGlobalScopeProvider;
 
+import com.google.common.collect.ImmutableList;
 import com.google.inject.Singleton;
 
 @Singleton
-public class ProblemUtil {
+public final class ProblemUtil {
+        private ProblemUtil() {
+                throw new IllegalStateException("This is a static utility class and should not be instantiated directly");
+        }
+
         public static final String SINGLETON_VARIABLE_PREFIX = "_";
 
         public static final String ENUM_NODE_NAME_QUOTE = "'";
 
+        public static final String NODE_CLASS_NAME = "node";
+
         public static boolean isSingletonVariableName(String name) {
                 return name != null && name.startsWith(SINGLETON_VARIABLE_PREFIX);
         }
@@ -28,4 +48,40 @@ public class ProblemUtil {
         public static boolean isNewNode(Node node) {
                 return node.eContainingFeature() == ProblemPackage.Literals.CLASS_DECLARATION__NEW_NODE;
         }
+
+        public static Optional<Problem> getBuiltInLibrary(EObject context) {
+                return Optional.ofNullable(context.eResource()).map(Resource::getResourceSet)
+                                .map(resourceSet -> resourceSet.getResource(ProblemGlobalScopeProvider.BULTIN_LIBRARY_URI, true))
+                                .map(Resource::getContents).filter(contents -> !contents.isEmpty()).map(contents -> contents.get(0))
+                                .filter(Problem.class::isInstance).map(Problem.class::cast);
+        }
+
+        public static Optional<ClassDeclaration> getNodeClassDeclaration(EObject context) {
+                return getBuiltInLibrary(context).flatMap(problem -> problem.getStatements().stream()
+                                .filter(ClassDeclaration.class::isInstance).map(ClassDeclaration.class::cast)
+                                .filter(declaration -> NODE_CLASS_NAME.equals(declaration.getName())).findFirst());
+        }
+
+        public static Collection<ClassDeclaration> getSuperclassesAndSelf(ClassDeclaration classDeclaration) {
+                Set<ClassDeclaration> found = new HashSet<>();
+                getNodeClassDeclaration(classDeclaration).ifPresent(found::add);
+                Deque<ClassDeclaration> queue = new ArrayDeque<>();
+                queue.addLast(classDeclaration);
+                while (!queue.isEmpty()) {
+                        ClassDeclaration current = queue.removeFirst();
+                        if (!found.contains(current)) {
+                                found.add(current);
+                                queue.addAll(current.getSuperTypes());
+                        }
+                }
+                return found;
+        }
+
+        public static Collection<ReferenceDeclaration> getAllReferenceDeclarations(ClassDeclaration classDeclaration) {
+                ImmutableList.Builder<ReferenceDeclaration> builder = ImmutableList.builder();
+                for (ClassDeclaration superclass : getSuperclassesAndSelf(classDeclaration)) {
+                        builder.addAll(superclass.getReferenceDeclarations());
+                }
+                return builder.build();
+        }
 }
diff --git a/org.eclipse.viatra.solver.language.parent/org.eclipse.viatra.solver.language/src/main/java/org/eclipse/viatra/solver/language/scoping/ProblemScopeProvider.java b/org.eclipse.viatra.solver.language.parent/org.eclipse.viatra.solver.language/src/main/java/org/eclipse/viatra/solver/language/scoping/ProblemScopeProvider.java
index 1849e647..c639f24c 100644
--- a/org.eclipse.viatra.solver.language.parent/org.eclipse.viatra.solver.language/src/main/java/org/eclipse/viatra/solver/language/scoping/ProblemScopeProvider.java
+++ b/org.eclipse.viatra.solver.language.parent/org.eclipse.viatra.solver.language/src/main/java/org/eclipse/viatra/solver/language/scoping/ProblemScopeProvider.java
@@ -4,15 +4,20 @@
 package org.eclipse.viatra.solver.language.scoping;
 
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.List;
 
 import org.eclipse.emf.ecore.EObject;
 import org.eclipse.emf.ecore.EReference;
+import org.eclipse.viatra.solver.language.ProblemUtil;
 import org.eclipse.viatra.solver.language.model.problem.Argument;
+import org.eclipse.viatra.solver.language.model.problem.ClassDeclaration;
 import org.eclipse.viatra.solver.language.model.problem.ExistentialQuantifier;
 import org.eclipse.viatra.solver.language.model.problem.PredicateDefinition;
 import org.eclipse.viatra.solver.language.model.problem.ProblemPackage;
+import org.eclipse.viatra.solver.language.model.problem.ReferenceDeclaration;
 import org.eclipse.viatra.solver.language.model.problem.Variable;
+import org.eclipse.xtext.EcoreUtil2;
 import org.eclipse.xtext.scoping.IScope;
 import org.eclipse.xtext.scoping.Scopes;
 
@@ -30,6 +35,8 @@ public class ProblemScopeProvider extends AbstractProblemScopeProvider {
                 IScope scope = super.getScope(context, reference);
                 if (reference == ProblemPackage.Literals.ARGUMENT__VARIABLE) {
                         return getVariableScope(context, scope);
+                } else if (reference == ProblemPackage.Literals.REFERENCE_DECLARATION__OPPOSITE) {
+                        return getOppositeScope(context, scope);
                 }
                 return scope;
         }
@@ -57,4 +64,18 @@ public class ProblemScopeProvider extends AbstractProblemScopeProvider {
                 }
                 return Scopes.scopeFor(variables);
         }
+
+        protected IScope getOppositeScope(EObject context, IScope delegateScope) {
+                ReferenceDeclaration referenceDeclaration = EcoreUtil2.getContainerOfType(context, ReferenceDeclaration.class);
+                if (referenceDeclaration == null) {
+                        return delegateScope;
+                }
+                ClassDeclaration classDeclaration = referenceDeclaration.getReferenceType();
+                if (classDeclaration == null) {
+                        return delegateScope;
+                }
+                Collection<ReferenceDeclaration> referenceDeclarations = ProblemUtil
+                                .getAllReferenceDeclarations(classDeclaration);
+                return Scopes.scopeFor(referenceDeclarations, delegateScope);
+        }
 }