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diff --git a/searchlib/src/main/java/com/yahoo/searchlib/rankingexpression/evaluation/Value.java b/searchlib/src/main/java/com/yahoo/searchlib/rankingexpression/evaluation/Value.java
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+++ b/searchlib/src/main/java/com/yahoo/searchlib/rankingexpression/evaluation/Value.java
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+// Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.searchlib.rankingexpression.evaluation;
+
+import com.yahoo.javacc.UnicodeUtilities;
+import com.yahoo.searchlib.rankingexpression.rule.Function;
+import com.yahoo.searchlib.rankingexpression.rule.TruthOperator;
+import com.yahoo.tensor.MapTensor;
+
+/**
+ * The result of a ranking expression evaluation.
+ * Concrete subclasses of this provides implementations of these methods or throws
+ * UnsupportedOperationException if the operation is not supported.
+ *
+ * @author  <a href="mailto:bratseth@yahoo-inc.com">Jon Bratseth</a>
+ * @since   5.1.5
+ */
+public abstract class Value {
+
+    private boolean frozen=false;
+
+    /** Returns this value as a double, or throws UnsupportedOperationException if it cannot be represented as a double */
+    public abstract double asDouble();
+
+    /** Returns this value as a double value, or throws UnsupportedOperationException if it cannot be represented as a double */
+    public DoubleValue asDoubleValue() {
+        return new DoubleValue(asDouble());
+    }
+
+    /** Returns true if this value can return itself as a double, i.e asDoubleValue will return a value and not throw */
+    public abstract boolean hasDouble();
+
+    /** Returns this value as a boolean. */
+    public abstract boolean asBoolean();
+
+    public abstract Value negate();
+
+    public abstract Value add(Value value);
+
+    public abstract Value subtract(Value value);
+
+    public abstract Value multiply(Value value);
+
+    public abstract Value divide(Value value);
+
+    /** Perform the comparison specified by the operator between this value and the given value */
+    public abstract boolean compare(TruthOperator operator,Value value);
+
+    /** Perform the given binary function on this value and the given value */
+    public abstract Value function(Function function,Value value);
+
+    /**
+     * Irreversibly makes this immutable. Overriders must always call super.freeze() and return this
+     *
+     * @return this for convenience
+     */
+    public Value freeze() {
+        frozen=true;
+        return this;
+    }
+
+    /** Returns true if this is immutable, false otherwise */
+    public final boolean isFrozen() { return frozen; }
+
+    /** Returns this is mutable, or a mutable copy otherwise */
+    public abstract Value asMutable();
+
+    @Override
+    public abstract String toString();
+
+    @Override
+    public abstract boolean equals(Object other);
+
+    @Override
+    public abstract int hashCode();
+
+    /**
+     * Parses the given string to a value and returns it.
+     * Different subtypes of Value will be returned depending on the string.
+     *
+     * @return a mutable Value
+     * @throws IllegalArgumentException if the given string is not parseable as a value
+     */
+    public static Value parse(String value) {
+        if (value.equals("true"))
+            return new BooleanValue(true);
+        else if (value.equals("false"))
+            return new BooleanValue(false);
+        else if (value.startsWith("\"") || value.startsWith("'"))
+            return new StringValue(UnicodeUtilities.unquote(value));
+        else if (value.startsWith("{"))
+            return new TensorValue(MapTensor.from(value));
+        else
+            return new DoubleValue(Double.parseDouble(value));
+    }
+
+}