Index: branches/DataAnalysis.Extensions/HeuristicLab.Problems.DataAnalysis/3.3/HeuristicLab.Problems.DataAnalysis-3.3.csproj
===================================================================
--- branches/DataAnalysis.Extensions/HeuristicLab.Problems.DataAnalysis/3.3/HeuristicLab.Problems.DataAnalysis-3.3.csproj	(revision 4860)
+++ branches/DataAnalysis.Extensions/HeuristicLab.Problems.DataAnalysis/3.3/HeuristicLab.Problems.DataAnalysis-3.3.csproj	(revision 4861)
@@ -198,4 +198,5 @@
     <Compile Include="SupportVectorMachine\SupportVectorMachineUtil.cs" />
     <Compile Include="Symbolic\ArithmeticExpressionGrammar.cs" />
+    <Compile Include="Symbolic\Formatters\SymbolicExpressionTreeSmalltalkStringFormatter.cs" />
     <Compile Include="Symbolic\FullFunctionalExpressionGrammar.cs" />
     <Compile Include="Symbolic\ISymbolicExpressionTreeInterpreter.cs" />
Index: branches/DataAnalysis.Extensions/HeuristicLab.Problems.DataAnalysis/3.3/Symbolic/Formatters/SymbolicExpressionTreeSmalltalkStringFormatter.cs
===================================================================
--- branches/DataAnalysis.Extensions/HeuristicLab.Problems.DataAnalysis/3.3/Symbolic/Formatters/SymbolicExpressionTreeSmalltalkStringFormatter.cs	(revision 4861)
+++ branches/DataAnalysis.Extensions/HeuristicLab.Problems.DataAnalysis/3.3/Symbolic/Formatters/SymbolicExpressionTreeSmalltalkStringFormatter.cs	(revision 4861)
@@ -0,0 +1,163 @@
+﻿#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.Text;
+using HeuristicLab.Core;
+using HeuristicLab.Common;
+using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
+using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding.Symbols;
+using HeuristicLab.Problems.DataAnalysis.Symbolic.Symbols;
+
+namespace HeuristicLab.Encodings.SymbolicExpressionTreeEncoding.Formatters {
+
+  [Item("SymbolicExpressionTreeSmalltalkStringFormatter", "String formatter for string representations of symbolic expression trees in Smalltalk syntax.")]
+  [StorableClass]
+  public class SymbolicExpressionTreeSmalltalkStringFormatter : NamedItem, ISymbolicExpressionTreeStringFormatter {
+
+    [StorableConstructor]
+    protected SymbolicExpressionTreeSmalltalkStringFormatter(bool deserializing) : base(deserializing) { }
+    protected SymbolicExpressionTreeSmalltalkStringFormatter(SymbolicExpressionTreeSmalltalkStringFormatter original, Cloner cloner) : base(original, cloner) { }
+    public SymbolicExpressionTreeSmalltalkStringFormatter()
+        : base() {
+      Name = "Smalltalk String Formatter";
+    }
+
+    public string Format(SymbolicExpressionTree symbolicExpressionTree) {
+      return FormatRecursively(symbolicExpressionTree.Root);
+    }
+
+    private string FormatRecursively(SymbolicExpressionTreeNode node) {
+      StringBuilder stringBuilder = new StringBuilder();
+
+      Symbol symbol = node.Symbol;
+      if (symbol is Addition) {
+        for (int i = 0; i < node.SubTrees.Count; i++) {
+          if (i > 0) stringBuilder.Append("+");
+          stringBuilder.Append("(");
+          stringBuilder.Append(FormatRecursively(node.SubTrees[i]));
+          stringBuilder.Append(")");
+        }
+      } else if (symbol is And) {
+        for (int i = 0; i < node.SubTrees.Count; i++) {
+          if (i > 0) stringBuilder.Append("&");
+          stringBuilder.Append("(");
+          stringBuilder.Append(FormatRecursively(node.SubTrees[i]));
+          stringBuilder.Append(")");
+        }
+      } else if (symbol is Average) {
+        stringBuilder.Append("(1/");
+        stringBuilder.Append(node.SubTrees.Count);
+        stringBuilder.Append(")*(");
+        for (int i = 0; i < node.SubTrees.Count; i++) {
+          if (i > 0) stringBuilder.Append("+");
+          stringBuilder.Append("(");
+          stringBuilder.Append(FormatRecursively(node.SubTrees[i]));
+          stringBuilder.Append(")");
+        }
+        stringBuilder.Append(")");
+      } else if (symbol is Constant) {
+        ConstantTreeNode constantTreeNode = node as ConstantTreeNode;
+        stringBuilder.Append(constantTreeNode.Value);
+      } else if (symbol is Cosine) {
+        stringBuilder.Append(FormatRecursively(node.SubTrees[0]));
+        stringBuilder.Append("cos");
+      } else if (symbol is Division) {
+        for (int i = 0; i < node.SubTrees.Count; i++) {
+          if (i > 0) stringBuilder.Append("/");
+          stringBuilder.Append("(");
+          stringBuilder.Append(FormatRecursively(node.SubTrees[i]));
+          stringBuilder.Append(")");
+        }
+      } else if (symbol is Exponential) {
+        stringBuilder.Append("not yet implemented");
+      } else if (symbol is GreaterThan) {
+        stringBuilder.Append("(");
+        stringBuilder.Append(FormatRecursively(node.SubTrees[0]));
+        stringBuilder.Append(">");
+        stringBuilder.Append(FormatRecursively(node.SubTrees[1]));
+        stringBuilder.Append(")");
+      } else if (symbol is IfThenElse) {
+        stringBuilder.Append("(");
+        stringBuilder.Append(FormatRecursively(node.SubTrees[0]));
+        stringBuilder.Append(" ifTrue: [");
+        stringBuilder.Append(FormatRecursively(node.SubTrees[1]));
+        stringBuilder.Append("] ifFalse: [");
+        stringBuilder.Append(FormatRecursively(node.SubTrees[2]));
+        stringBuilder.Append("] )");
+      } else if (symbol is LaggedVariable) {
+        stringBuilder.Append("not implemented");
+      } else if (symbol is LessThan) {
+        stringBuilder.Append("(");
+        stringBuilder.Append(FormatRecursively(node.SubTrees[0]));
+        stringBuilder.Append("<");
+        stringBuilder.Append(FormatRecursively(node.SubTrees[1]));
+        stringBuilder.Append(")");
+      } else if (symbol is Logarithm) {
+        stringBuilder.Append(FormatRecursively(node.SubTrees[0]));
+        stringBuilder.Append("log");
+      } else if (symbol is Multiplication) {
+        for (int i = 0; i < node.SubTrees.Count; i++) {
+          if (i > 0) stringBuilder.Append("*");
+          stringBuilder.Append("(");
+          stringBuilder.Append(FormatRecursively(node.SubTrees[i]));
+          stringBuilder.Append(")");
+        }
+      } else if (symbol is Not) {
+        stringBuilder.Append("!");
+        stringBuilder.Append(FormatRecursively(node.SubTrees[0]));
+      } else if (symbol is Or) {
+        for (int i = 0; i < node.SubTrees.Count; i++) {
+          if (i > 0) stringBuilder.Append("|");
+          stringBuilder.Append("(");
+          stringBuilder.Append(FormatRecursively(node.SubTrees[i]));
+          stringBuilder.Append(")");
+        }
+      } else if (symbol is Sine) {
+        stringBuilder.Append(FormatRecursively(node.SubTrees[0]));
+        stringBuilder.Append("sin");
+      } else if (symbol is Subtraction) {
+        for (int i = 0; i < node.SubTrees.Count; i++) {
+          if (i > 0) stringBuilder.Append("-");
+          stringBuilder.Append("(");
+          stringBuilder.Append(FormatRecursively(node.SubTrees[i]));
+          stringBuilder.Append(")");
+        }
+      } else if (symbol is Tangent) {
+        stringBuilder.Append(FormatRecursively(node.SubTrees[0]));
+        stringBuilder.Append("tan");
+      } else if (symbol is HeuristicLab.Problems.DataAnalysis.Symbolic.Symbols.Variable) {
+        stringBuilder.Append("not yet implemented");
+      }
+
+      else {
+        stringBuilder.Append("ERROR");
+      }
+
+      return stringBuilder.ToString();
+    }
+
+    public override IDeepCloneable Clone(Cloner cloner) {
+      return new SymbolicExpressionTreeSmalltalkStringFormatter(this, cloner);
+    }
+
+  }
+
+}
