1 files changed, 109 insertions, 0 deletions

diff --git a/subprojects/language/src/main/java/tools/refinery/language/scoping/NormalizedSelectable.java b/subprojects/language/src/main/java/tools/refinery/language/scoping/NormalizedSelectable.java
new file mode 100644
index 00000000..09fe4716
--- /dev/null
+++ b/subprojects/language/src/main/java/tools/refinery/language/scoping/NormalizedSelectable.java
@@ -0,0 +1,109 @@
+/*
+ * SPDX-FileCopyrightText: 2024 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
+package tools.refinery.language.scoping;
+
+import com.google.common.collect.Iterables;
+import org.eclipse.emf.ecore.EClass;
+import org.eclipse.emf.ecore.EObject;
+import org.eclipse.xtext.naming.QualifiedName;
+import org.eclipse.xtext.resource.IEObjectDescription;
+import org.eclipse.xtext.resource.ISelectable;
+import org.eclipse.xtext.resource.impl.AliasedEObjectDescription;
+
+import java.util.Iterator;
+import java.util.List;
+import java.util.NoSuchElementException;
+
+class NormalizedSelectable implements ISelectable {
+        private final ISelectable delegateSelectable;
+        private final QualifiedName originalPrefix;
+        private final QualifiedName normalizedPrefix;
+
+        public NormalizedSelectable(ISelectable delegateSelectable, QualifiedName originalPrefix,
+                                                                QualifiedName normalizedPrefix) {
+                if (originalPrefix.equals(QualifiedName.EMPTY)) {
+                        throw new IllegalArgumentException("Cannot normalize empty qualified name prefix");
+                }
+                this.delegateSelectable = delegateSelectable;
+                this.originalPrefix = originalPrefix;
+                this.normalizedPrefix = normalizedPrefix;
+        }
+
+        @Override
+        public boolean isEmpty() {
+                return delegateSelectable.isEmpty();
+        }
+
+        @Override
+        public Iterable<IEObjectDescription> getExportedObjects() {
+                var delegateIterable = delegateSelectable.getExportedObjects();
+                return getAliasedElements(delegateIterable);
+        }
+
+        @Override
+        public Iterable<IEObjectDescription> getExportedObjects(EClass type, QualifiedName name, boolean ignoreCase) {
+                boolean startsWith = ignoreCase ? name.startsWithIgnoreCase(normalizedPrefix) :
+                                name.startsWith(normalizedPrefix);
+                if (startsWith && name.getSegmentCount() > normalizedPrefix.getSegmentCount()) {
+                        var originalName = originalPrefix.append(name.skipFirst(normalizedPrefix.getSegmentCount()));
+                        return Iterables.transform(
+                                        delegateSelectable.getExportedObjects(type, originalName, ignoreCase),
+                                        description -> {
+                                                var normalizedName = normalizedPrefix.append(
+                                                                description.getName().skipFirst(originalPrefix.getSegmentCount()));
+                                                return new AliasedEObjectDescription(normalizedName, description);
+                                        });
+                }
+                return List.of();
+        }
+
+        @Override
+        public Iterable<IEObjectDescription> getExportedObjectsByType(EClass type) {
+                var delegateIterable = delegateSelectable.getExportedObjectsByType(type);
+                return getAliasedElements(delegateIterable);
+        }
+
+        @Override
+        public Iterable<IEObjectDescription> getExportedObjectsByObject(EObject object) {
+                var delegateIterable = delegateSelectable.getExportedObjectsByObject(object);
+                return getAliasedElements(delegateIterable);
+        }
+
+        private Iterable<IEObjectDescription> getAliasedElements(Iterable<IEObjectDescription> delegateIterable) {
+                return () -> new Iterator<>() {
+                        private final Iterator<IEObjectDescription> delegateIterator = delegateIterable.iterator();
+                        private IEObjectDescription next = computeNext();
+
+                        @Override
+                        public boolean hasNext() {
+                                return next != null;
+                        }
+
+                        @Override
+                        public IEObjectDescription next() {
+                                if (!hasNext()) {
+                                        throw new NoSuchElementException();
+                                }
+                                var current = next;
+                                next = computeNext();
+                                return current;
+                        }
+
+                        private IEObjectDescription computeNext() {
+                                while (delegateIterator.hasNext()) {
+                                        var description = delegateIterator.next();
+                                        var qualifiedName = description.getName();
+                                        if (qualifiedName.startsWith(originalPrefix) &&
+                                                        qualifiedName.getSegmentCount() > originalPrefix.getSegmentCount()) {
+                                                var alias = normalizedPrefix.append(qualifiedName.skipFirst(originalPrefix.getSegmentCount()));
+                                                return new AliasedEObjectDescription(alias, description);
+                                        }
+                                }
+                                return null;
+                        }
+                };
+        }
+}