1 files changed, 88 insertions, 0 deletions

diff --git a/subprojects/logic/src/main/java/tools/refinery/logic/term/Variable.java b/subprojects/logic/src/main/java/tools/refinery/logic/term/Variable.java
new file mode 100644
index 00000000..28aad21b
--- /dev/null
+++ b/subprojects/logic/src/main/java/tools/refinery/logic/term/Variable.java
@@ -0,0 +1,88 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
+package tools.refinery.logic.term;
+
+import org.jetbrains.annotations.Nullable;
+import tools.refinery.logic.dnf.DnfUtils;
+
+import java.util.Objects;
+import java.util.Optional;
+
+public abstract sealed class Variable permits AnyDataVariable, NodeVariable {
+        private final String explicitName;
+        private final String uniqueName;
+
+        protected Variable(String name) {
+                this.explicitName = name;
+                uniqueName = DnfUtils.generateUniqueName(name);
+        }
+
+        public abstract Optional<Class<?>> tryGetType();
+
+        public String getName() {
+                return explicitName == null ? uniqueName : explicitName;
+        }
+
+        protected String getExplicitName() {
+                return explicitName;
+        }
+
+        public boolean isExplicitlyNamed() {
+                return explicitName != null;
+        }
+
+        public String getUniqueName() {
+                return uniqueName;
+        }
+
+        public abstract Variable renew(@Nullable String name);
+
+        public abstract Variable renew();
+
+        public abstract boolean isNodeVariable();
+
+        public abstract boolean isDataVariable();
+
+        public abstract NodeVariable asNodeVariable();
+
+        public abstract <T> DataVariable<T> asDataVariable(Class<T> type);
+
+        public abstract int hashCodeWithSubstitution(int sequenceNumber);
+
+        @Override
+        public String toString() {
+                return getName();
+        }
+
+        @Override
+        public boolean equals(Object o) {
+                if (this == o) return true;
+                if (o == null || getClass() != o.getClass()) return false;
+                Variable variable = (Variable) o;
+                return Objects.equals(uniqueName, variable.uniqueName);
+        }
+
+        @Override
+        public int hashCode() {
+                return Objects.hash(uniqueName);
+        }
+
+        public static NodeVariable of(@Nullable String name) {
+                return new NodeVariable(name);
+        }
+
+        public static NodeVariable of() {
+                return of((String) null);
+        }
+
+        public static <T> DataVariable<T> of(@Nullable String name, Class<T> type) {
+                return new DataVariable<>(name, type);
+        }
+
+        public static <T> DataVariable<T> of(Class<T> type) {
+                return of(null, type);
+        }
+}