1 files changed, 83 insertions, 0 deletions

diff --git a/subprojects/language-semantics/src/main/java/tools/refinery/language/semantics/model/internal/NullaryMutableSeed.java b/subprojects/language-semantics/src/main/java/tools/refinery/language/semantics/model/internal/NullaryMutableSeed.java
new file mode 100644
index 00000000..80644b1f
--- /dev/null
+++ b/subprojects/language-semantics/src/main/java/tools/refinery/language/semantics/model/internal/NullaryMutableSeed.java
@@ -0,0 +1,83 @@
+/*
+ * SPDX-FileCopyrightText: 2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
+package tools.refinery.language.semantics.model.internal;
+
+import tools.refinery.store.map.Cursor;
+import tools.refinery.store.map.Cursors;
+import tools.refinery.store.representation.TruthValue;
+import tools.refinery.store.tuple.Tuple;
+
+class NullaryMutableSeed implements MutableSeed<TruthValue> {
+        private DecisionTreeValue value;
+
+        public NullaryMutableSeed(TruthValue reducedValue) {
+
+                value = DecisionTreeValue.fromTruthValue(reducedValue);
+        }
+
+        @Override
+        public int arity() {
+                return 0;
+        }
+
+        @Override
+        public Class<TruthValue> valueType() {
+                return TruthValue.class;
+        }
+
+        @Override
+        public TruthValue reducedValue() {
+                return value.getTruthValue();
+        }
+
+        @Override
+        public TruthValue get(Tuple key) {
+                validateKey(key);
+                return reducedValue();
+        }
+
+        private static void validateKey(Tuple key) {
+                if (key.getSize() > 0) {
+                        throw new IllegalArgumentException("Invalid key: " + key);
+                }
+        }
+
+        @Override
+        public Cursor<Tuple, TruthValue> getCursor(TruthValue defaultValue, int nodeCount) {
+                if (value == DecisionTreeValue.UNSET || value.getTruthValue() == defaultValue) {
+                        return Cursors.empty();
+                }
+                return Cursors.singleton(Tuple.of(), value.getTruthValue());
+        }
+
+        @Override
+        public void mergeValue(Tuple tuple, TruthValue value) {
+                this.value = DecisionTreeValue.fromTruthValue(this.value.merge(value));
+        }
+
+        @Override
+        public void setIfMissing(Tuple tuple, TruthValue value) {
+                validateKey(tuple);
+                setAllMissing(value);
+        }
+
+        @Override
+        public void setAllMissing(TruthValue value) {
+                if (this.value == DecisionTreeValue.UNSET) {
+                        this.value = DecisionTreeValue.fromTruthValue(value);
+                }
+        }
+
+        @Override
+        public void overwriteValues(MutableSeed<TruthValue> other) {
+                if (!(other instanceof NullaryMutableSeed nullaryMutableSeed)) {
+                        throw new IllegalArgumentException("Incompatible overwrite: " + other);
+                }
+                if (nullaryMutableSeed.value != DecisionTreeValue.UNSET) {
+                        value = nullaryMutableSeed.value;
+                }
+        }
+}