1 files changed, 48 insertions, 0 deletions

diff --git a/subprojects/store-query/src/main/java/tools/refinery/store/query/term/NodeVariable.java b/subprojects/store-query/src/main/java/tools/refinery/store/query/term/NodeVariable.java
new file mode 100644
index 00000000..7419aaad
--- /dev/null
+++ b/subprojects/store-query/src/main/java/tools/refinery/store/query/term/NodeVariable.java
@@ -0,0 +1,48 @@
+package tools.refinery.store.query.term;
+
+import org.jetbrains.annotations.Nullable;
+import tools.refinery.store.query.literal.ConstantLiteral;
+import tools.refinery.store.query.literal.EquivalenceLiteral;
+
+public final class NodeVariable extends Variable {
+        NodeVariable(@Nullable String name) {
+                super(name);
+        }
+
+        @Override
+        public NodeSort getSort() {
+                return NodeSort.INSTANCE;
+        }
+
+        @Override
+        public NodeVariable renew(@Nullable String name) {
+                return Variable.of(name);
+        }
+
+        @Override
+        public NodeVariable renew() {
+                return renew(getExplicitName());
+        }
+
+        @Override
+        public NodeVariable asNodeVariable() {
+                return this;
+        }
+
+        @Override
+        public <T> DataVariable<T> asDataVariable(Class<T> type) {
+                throw new IllegalStateException("%s is a node variable".formatted(this));
+        }
+
+        public ConstantLiteral isConstant(int value) {
+                return new ConstantLiteral(this, value);
+        }
+
+        public EquivalenceLiteral isEquivalent(NodeVariable other) {
+                return new EquivalenceLiteral(true, this, other);
+        }
+
+        public EquivalenceLiteral notEquivalent(NodeVariable other) {
+                return new EquivalenceLiteral(false, this, other);
+        }
+}