Index: trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/GeneralSymbolicExpressionTreeEvaluator.cs
===================================================================
--- trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/GeneralSymbolicExpressionTreeEvaluator.cs	(revision 3256)
+++ trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/GeneralSymbolicExpressionTreeEvaluator.cs	(revision 3256)
@@ -0,0 +1,52 @@
+﻿#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2010 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
+ *
+ * This file is part of HeuristicLab.
+ *
+ * HeuristicLab is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * HeuristicLab is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
+ */
+#endregion
+
+using System;
+using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
+using HeuristicLab.Core;
+using System.Collections.Generic;
+using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
+using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding.GeneralSymbols;
+
+namespace HeuristicLab.Encodings.SymbolicExpressionTreeEncoding {
+  /// <summary>
+  /// Evaluates FunctionTrees recursively by interpretation of the function symbols in each node.
+  /// Simple unoptimized code, general symbolic expressions only.
+  /// Not thread-safe!
+  /// </summary>
+  [StorableClass]
+  [Item("GeneralSymbolicExpressionTreeEvaluator", "Default evaluator for symbolic expression trees.")]
+  public class GeneralSymbolicExpressionTreeEvaluator : Item {
+    public virtual double Evaluate(SymbolicExpressionTreeNode node) {
+      if (node.Symbol is Addition) {
+        return Evaluate(node.SubTrees[0]) + Evaluate(node.SubTrees[1]);
+      } else if (node.Symbol is Subtraction) {
+        return Evaluate(node.SubTrees[0]) - Evaluate(node.SubTrees[1]);
+      } else if (node.Symbol is Multiplication) {
+        return Evaluate(node.SubTrees[0]) * Evaluate(node.SubTrees[1]);
+      } else if (node.Symbol is Division) {
+        return Evaluate(node.SubTrees[0]) / Evaluate(node.SubTrees[1]);
+      } else {
+        throw new NotSupportedException("Tree contains unknown symbol: " + node.Symbol.Name);
+      }
+    }
+  }
+}
Index: trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding-3.3.csproj
===================================================================
--- trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding-3.3.csproj	(revision 3255)
+++ trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding-3.3.csproj	(revision 3256)
@@ -83,4 +83,5 @@
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="SymbolicExpressionTreeTerminalNode.cs" />
     <Compile Include="Crossovers\SubtreeCrossover.cs" />
     <Compile Include="Interfaces\ISymbolicExpressionGrammar.cs" />
@@ -95,4 +96,11 @@
     <Compile Include="SymbolicExpressionTreeCrossover.cs" />
     <Compile Include="SymbolicExpressionTreeNode.cs" />
+    <Compile Include="Symbols\Addition.cs" />
+    <Compile Include="Symbols\Prog.cs" />
+    <Compile Include="GeneralSymbolicExpressionTreeEvaluator.cs" />
+    <Compile Include="Symbols\StartSymbol.cs" />
+    <Compile Include="Symbols\Division.cs" />
+    <Compile Include="Symbols\Multiplication.cs" />
+    <Compile Include="Symbols\Subtraction.cs" />
   </ItemGroup>
   <ItemGroup>
Index: trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/SymbolicExpressionTreeTerminalNode.cs
===================================================================
--- trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/SymbolicExpressionTreeTerminalNode.cs	(revision 3256)
+++ trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/SymbolicExpressionTreeTerminalNode.cs	(revision 3256)
@@ -0,0 +1,54 @@
+#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2008 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
+ *
+ * This file is part of HeuristicLab.
+ *
+ * HeuristicLab is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * HeuristicLab is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
+ */
+#endregion
+
+using System;
+using System.Collections.Generic;
+using System.Text;
+using HeuristicLab.Core;
+using System.Xml;
+using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
+using HeuristicLab.Data;
+
+namespace HeuristicLab.Encodings.SymbolicExpressionTreeEncoding {
+  public abstract class SymbolicExpressionTreeTerminalNode : SymbolicExpressionTreeNode {
+    private static List<SymbolicExpressionTreeNode> emptyList = new List<SymbolicExpressionTreeNode>();
+
+    protected SymbolicExpressionTreeTerminalNode(Symbol symbol) : base(symbol) { }
+    protected SymbolicExpressionTreeTerminalNode(SymbolicExpressionTreeTerminalNode original)
+      : base(original) {
+    }
+
+    protected internal override void AddSubTree(SymbolicExpressionTreeNode tree) {
+      throw new NotSupportedException();
+    }
+    protected internal override void InsertSubTree(int index, SymbolicExpressionTreeNode tree) {
+      throw new NotSupportedException();
+    }
+    protected internal override void RemoveSubTree(int index) {
+      throw new NotSupportedException();
+    }
+    public override IList<SymbolicExpressionTreeNode> SubTrees {
+      get {
+        return SymbolicExpressionTreeTerminalNode.emptyList;
+      }
+    }
+  }
+}
Index: trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/Symbols/Addition.cs
===================================================================
--- trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/Symbols/Addition.cs	(revision 3256)
+++ trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/Symbols/Addition.cs	(revision 3256)
@@ -0,0 +1,25 @@
+#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2010 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
+ *
+ * This file is part of HeuristicLab.
+ *
+ * HeuristicLab is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * HeuristicLab is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
+ */
+#endregion
+
+namespace HeuristicLab.Encodings.SymbolicExpressionTreeEncoding.GeneralSymbols {
+  public sealed class Addition : Symbol {
+  }
+}
Index: trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/Symbols/Division.cs
===================================================================
--- trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/Symbols/Division.cs	(revision 3256)
+++ trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/Symbols/Division.cs	(revision 3256)
@@ -0,0 +1,25 @@
+#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2010 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
+ *
+ * This file is part of HeuristicLab.
+ *
+ * HeuristicLab is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * HeuristicLab is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
+ */
+#endregion
+
+namespace HeuristicLab.Encodings.SymbolicExpressionTreeEncoding.GeneralSymbols {
+  public sealed class Division : Symbol {
+  }
+}
Index: trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/Symbols/Multiplication.cs
===================================================================
--- trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/Symbols/Multiplication.cs	(revision 3256)
+++ trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/Symbols/Multiplication.cs	(revision 3256)
@@ -0,0 +1,25 @@
+#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2010 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
+ *
+ * This file is part of HeuristicLab.
+ *
+ * HeuristicLab is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * HeuristicLab is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
+ */
+#endregion
+
+namespace HeuristicLab.Encodings.SymbolicExpressionTreeEncoding.GeneralSymbols {
+  public sealed class Multiplication : Symbol {
+  }
+}
Index: trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/Symbols/Prog.cs
===================================================================
--- trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/Symbols/Prog.cs	(revision 3256)
+++ trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/Symbols/Prog.cs	(revision 3256)
@@ -0,0 +1,25 @@
+#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2010 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
+ *
+ * This file is part of HeuristicLab.
+ *
+ * HeuristicLab is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * HeuristicLab is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
+ */
+#endregion
+
+namespace HeuristicLab.Encodings.SymbolicExpressionTreeEncoding.GeneralSymbols {
+  public sealed class Prog : Symbol {
+  }
+}
Index: trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/Symbols/StartSymbol.cs
===================================================================
--- trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/Symbols/StartSymbol.cs	(revision 3256)
+++ trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/Symbols/StartSymbol.cs	(revision 3256)
@@ -0,0 +1,25 @@
+#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2010 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
+ *
+ * This file is part of HeuristicLab.
+ *
+ * HeuristicLab is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * HeuristicLab is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
+ */
+#endregion
+
+namespace HeuristicLab.Encodings.SymbolicExpressionTreeEncoding.GeneralSymbols {
+  public sealed class StartSymbol : Symbol {
+  }
+}
Index: trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/Symbols/Subtraction.cs
===================================================================
--- trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/Symbols/Subtraction.cs	(revision 3256)
+++ trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/Symbols/Subtraction.cs	(revision 3256)
@@ -0,0 +1,25 @@
+#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2010 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
+ *
+ * This file is part of HeuristicLab.
+ *
+ * HeuristicLab is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * HeuristicLab is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
+ */
+#endregion
+
+namespace HeuristicLab.Encodings.SymbolicExpressionTreeEncoding.GeneralSymbols {
+  public sealed class Subtraction : Symbol {
+  }
+}
