1 files changed, 104 insertions, 0 deletions

diff --git a/subprojects/viatra-runtime-localsearch/src/main/java/tools/refinery/viatra/runtime/localsearch/operations/extend/ExpressionEval.java b/subprojects/viatra-runtime-localsearch/src/main/java/tools/refinery/viatra/runtime/localsearch/operations/extend/ExpressionEval.java
new file mode 100644
index 00000000..7186f4ac
--- /dev/null
+++ b/subprojects/viatra-runtime-localsearch/src/main/java/tools/refinery/viatra/runtime/localsearch/operations/extend/ExpressionEval.java
@@ -0,0 +1,104 @@
+/*******************************************************************************
+ * Copyright (c) 2010-2013, Zoltan Ujhelyi, Istvan Rath and Daniel Varro
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-v20.html.
+ * 
+ * SPDX-License-Identifier: EPL-2.0
+ *******************************************************************************/
+package tools.refinery.viatra.runtime.localsearch.operations.extend;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.function.Function;
+
+import tools.refinery.viatra.runtime.localsearch.MatchingFrame;
+import tools.refinery.viatra.runtime.localsearch.matcher.ISearchContext;
+import tools.refinery.viatra.runtime.localsearch.operations.ISearchOperation;
+import tools.refinery.viatra.runtime.localsearch.operations.MatchingFrameValueProvider;
+import tools.refinery.viatra.runtime.matchers.psystem.IExpressionEvaluator;
+
+/**
+ * Calculates the result of an expression and stores it inside a variable for future reference.
+ * 
+ * @author Zoltan Ujhelyi
+ * 
+ */
+public class ExpressionEval implements ISearchOperation {
+
+    private class Executor extends SingleValueExtendOperationExecutor<Object> {
+
+        public Executor(int position) {
+            super(position);
+        }
+        
+        @Override
+        public Iterator<?> getIterator(MatchingFrame frame, ISearchContext context) {
+            try {
+                Object result = evaluator.evaluateExpression(new MatchingFrameValueProvider(frame, nameMap));
+                if (!unwind && result != null){
+                    return Collections.singletonList(result).iterator();
+                } else if (unwind && result instanceof Set<?>) {
+                    return ((Set<?>)result).iterator();
+                } else {
+                    return Collections.emptyIterator();
+                }
+            } catch (Exception e) {
+                context.getLogger().warn("Error while evaluating expression", e);
+                return Collections.emptyIterator();
+            }
+        }
+        
+        @Override
+        public ISearchOperation getOperation() {
+            return ExpressionEval.this;
+        }
+    }
+    
+    private final IExpressionEvaluator evaluator;
+    private final boolean unwind;
+    private final Map<String, Integer> nameMap;
+    private final int position;
+
+    public ExpressionEval(IExpressionEvaluator evaluator, Map<String, Integer> nameMap, int position) {
+        this(evaluator, nameMap, false, position);
+    }
+    
+    /**
+     * @since 2.7
+     */
+    public ExpressionEval(IExpressionEvaluator evaluator, Map<String, Integer> nameMap, boolean unwind, int position) {
+        this.evaluator = evaluator;
+        this.nameMap = nameMap;
+        this.unwind = unwind;
+        this.position = position;
+    }
+    
+    @Override
+    public String toString() {
+        return toString(Object::toString);
+    }
+    
+    @Override
+    public String toString(Function<Integer, String> variableMapping) {
+        return "extend    -"+variableMapping.apply(position)+" = expression "+evaluator.getShortDescription();
+    }
+    
+    @Override
+    public ISearchOperationExecutor createExecutor() {
+        return new Executor(position);
+    }
+
+    @Override
+    public List<Integer> getVariablePositions() {
+        // XXX not sure if this is the correct implementation to get the affected variable indicies
+        List<Integer> variables = new ArrayList<>();
+        variables.addAll(nameMap.values());
+        return variables;
+    }
+    
+}