1 files changed, 29 insertions, 0 deletions

diff --git a/subprojects/logic/src/main/java/tools/refinery/logic/substitution/Substitution.java b/subprojects/logic/src/main/java/tools/refinery/logic/substitution/Substitution.java
new file mode 100644
index 00000000..8fc700bc
--- /dev/null
+++ b/subprojects/logic/src/main/java/tools/refinery/logic/substitution/Substitution.java
@@ -0,0 +1,29 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
+package tools.refinery.logic.substitution;
+
+import tools.refinery.logic.term.DataVariable;
+import tools.refinery.logic.term.NodeVariable;
+import tools.refinery.logic.term.Variable;
+
+@FunctionalInterface
+public interface Substitution {
+        Variable getSubstitute(Variable variable);
+
+        default NodeVariable getTypeSafeSubstitute(NodeVariable variable) {
+                var substitute = getSubstitute(variable);
+                return substitute.asNodeVariable();
+        }
+
+        default <T> DataVariable<T> getTypeSafeSubstitute(DataVariable<T> variable) {
+                var substitute = getSubstitute(variable);
+                return substitute.asDataVariable(variable.getType());
+        }
+
+        static SubstitutionBuilder builder() {
+                return new SubstitutionBuilder();
+        }
+}