Index: /trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding.Views/3.3/SymbolicExpressionView.Designer.cs
===================================================================
--- /trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding.Views/3.3/SymbolicExpressionView.Designer.cs	(revision 5415)
+++ /trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding.Views/3.3/SymbolicExpressionView.Designer.cs	(revision 5416)
@@ -46,21 +46,52 @@
     private void InitializeComponent() {
       this.textBox = new System.Windows.Forms.TextBox();
+      this.formattersComboBox = new System.Windows.Forms.ComboBox();
+      this.formatterLabel = new System.Windows.Forms.Label();
       this.SuspendLayout();
       // 
       // textBox
       // 
-      this.textBox.Dock = System.Windows.Forms.DockStyle.Fill;
-      this.textBox.Location = new System.Drawing.Point(0, 0);
+      this.textBox.Anchor = ((System.Windows.Forms.AnchorStyles)((((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Bottom)
+                  | System.Windows.Forms.AnchorStyles.Left)
+                  | System.Windows.Forms.AnchorStyles.Right)));
+      this.textBox.BackColor = System.Drawing.Color.White;
+      this.textBox.Location = new System.Drawing.Point(3, 30);
       this.textBox.Multiline = true;
       this.textBox.Name = "textBox";
-      this.textBox.Size = new System.Drawing.Size(150, 150);
+      this.textBox.ReadOnly = true;
+      this.textBox.ScrollBars = System.Windows.Forms.ScrollBars.Vertical;
+      this.textBox.Size = new System.Drawing.Size(475, 282);
       this.textBox.TabIndex = 0;
       // 
-      // SymbolicExpressionTreeView
+      // formattersComboBox
+      // 
+      this.formattersComboBox.Anchor = ((System.Windows.Forms.AnchorStyles)(((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Left)
+                  | System.Windows.Forms.AnchorStyles.Right)));
+      this.formattersComboBox.DropDownStyle = System.Windows.Forms.ComboBoxStyle.DropDownList;
+      this.formattersComboBox.FormattingEnabled = true;
+      this.formattersComboBox.Location = new System.Drawing.Point(72, 3);
+      this.formattersComboBox.Name = "formattersComboBox";
+      this.formattersComboBox.Size = new System.Drawing.Size(406, 21);
+      this.formattersComboBox.TabIndex = 1;
+      this.formattersComboBox.SelectedIndexChanged += new System.EventHandler(this.formattersComboBox_SelectedIndexChanged);
+      // 
+      // formatterLabel
+      // 
+      this.formatterLabel.AutoSize = true;
+      this.formatterLabel.Location = new System.Drawing.Point(3, 6);
+      this.formatterLabel.Name = "formatterLabel";
+      this.formatterLabel.Size = new System.Drawing.Size(54, 13);
+      this.formatterLabel.TabIndex = 2;
+      this.formatterLabel.Text = "Formatter:";
+      // 
+      // SymbolicExpressionView
       // 
       this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
       this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
+      this.Controls.Add(this.formatterLabel);
+      this.Controls.Add(this.formattersComboBox);
       this.Controls.Add(this.textBox);
-      this.Name = "SymbolicExpressionTreeView";
+      this.Name = "SymbolicExpressionView";
+      this.Size = new System.Drawing.Size(481, 315);
       this.ResumeLayout(false);
       this.PerformLayout();
@@ -71,4 +102,6 @@
 
     private System.Windows.Forms.TextBox textBox;
+    private System.Windows.Forms.ComboBox formattersComboBox;
+    private System.Windows.Forms.Label formatterLabel;
   }
 }
Index: /trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding.Views/3.3/SymbolicExpressionView.cs
===================================================================
--- /trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding.Views/3.3/SymbolicExpressionView.cs	(revision 5415)
+++ /trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding.Views/3.3/SymbolicExpressionView.cs	(revision 5416)
@@ -23,4 +23,7 @@
 using HeuristicLab.MainForm;
 using HeuristicLab.MainForm.WindowsForms;
+using HeuristicLab.PluginInfrastructure;
+using System.Collections.Generic;
+using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding.Formatters;
 
 namespace HeuristicLab.Encodings.SymbolicExpressionTreeEncoding.Views {
@@ -28,5 +31,6 @@
   [Content(typeof(SymbolicExpressionTree), false)]
   public partial class SymbolicExpressionView : AsynchronousContentView {
-    private SymbolicExpressionTreeStringFormatter treeFormatter;
+
+    List<ISymbolicExpressionTreeStringFormatter> treeFormattersList = new List<ISymbolicExpressionTreeStringFormatter>();
 
     public new SymbolicExpressionTree Content {
@@ -37,13 +41,26 @@
     public SymbolicExpressionView() {
       InitializeComponent();
-      treeFormatter = new SymbolicExpressionTreeStringFormatter();
+      IEnumerable<ISymbolicExpressionTreeStringFormatter> formatters = ApplicationManager.Manager.GetInstances<ISymbolicExpressionTreeStringFormatter>();
+      treeFormattersList = new List<ISymbolicExpressionTreeStringFormatter>();
+      int selectedIndex = -1;
+      foreach (ISymbolicExpressionTreeStringFormatter formatter in formatters) {
+        if (formatter is SymbolicExpressionTreeStringFormatter)
+          selectedIndex = treeFormattersList.Count;
+        treeFormattersList.Add(formatter);
+        formattersComboBox.Items.Add(formatter.Name);
+      }
+      formattersComboBox.SelectedIndex = selectedIndex;
     }
 
     protected override void OnContentChanged() {
       base.OnContentChanged();
-      if (Content == null)
+      UpdateTextbox();
+    }
+
+    private void UpdateTextbox() {
+      if (Content == null || formattersComboBox.SelectedIndex < 0)
         textBox.Text = string.Empty;
       else
-        textBox.Text = treeFormatter.Format(Content);
+        textBox.Text = treeFormattersList[formattersComboBox.SelectedIndex].Format(Content);
     }
 
@@ -53,4 +70,8 @@
       textBox.ReadOnly = ReadOnly;
     }
+
+    private void formattersComboBox_SelectedIndexChanged(object sender, System.EventArgs e) {
+      UpdateTextbox();
+    }
   }
 }
Index: /trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/Formatters/SymbolicExpressionTreeStringFormatter.cs
===================================================================
--- /trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/Formatters/SymbolicExpressionTreeStringFormatter.cs	(revision 5416)
+++ /trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/Formatters/SymbolicExpressionTreeStringFormatter.cs	(revision 5416)
@@ -0,0 +1,80 @@
+﻿#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;
+
+namespace HeuristicLab.Encodings.SymbolicExpressionTreeEncoding.Formatters {
+
+  [Item("SymbolicExpressionTreeStringFormatter", "The default string formatter for symbolic expression trees.")]
+  [StorableClass]
+  public class SymbolicExpressionTreeStringFormatter : NamedItem, ISymbolicExpressionTreeStringFormatter {
+
+    public bool Indent { get; set; }
+
+    [StorableConstructor]
+    protected SymbolicExpressionTreeStringFormatter(bool deserializing) : base(deserializing) { }
+    protected SymbolicExpressionTreeStringFormatter(SymbolicExpressionTreeStringFormatter original, Cloner cloner)
+      : base(original, cloner) {
+      Indent = original.Indent;
+    }
+    public SymbolicExpressionTreeStringFormatter()
+      : base() {
+      Name = "Default String Formatter";
+      Indent = true;
+    }
+
+    public string Format(SymbolicExpressionTree symbolicExpressionTree) {
+      return FormatRecursively(symbolicExpressionTree.Root, 0);
+    }
+
+    private string FormatRecursively(SymbolicExpressionTreeNode node, int indentLength) {
+      StringBuilder strBuilder = new StringBuilder();
+      if (Indent) strBuilder.Append(' ', indentLength);
+      strBuilder.Append("(");
+      // internal nodes or leaf nodes?
+      if (node.SubTrees.Count > 0) {
+        // symbol on same line as '('
+        strBuilder.AppendLine(node.ToString());
+        // each subtree expression on a new line
+        // and closing ')' also on new line
+        foreach (var subtree in node.SubTrees) {
+          strBuilder.AppendLine(FormatRecursively(subtree, indentLength + 2));
+        }
+        if (Indent) strBuilder.Append(' ', indentLength);
+        strBuilder.Append(")");
+      } else {
+        // symbol in the same line with as '(' and ')'
+        strBuilder.Append(node.ToString());
+        strBuilder.Append(")");
+      }
+      return strBuilder.ToString();
+    }
+
+    public override IDeepCloneable Clone(Cloner cloner) {
+      return new SymbolicExpressionTreeStringFormatter(this, cloner);
+    }
+
+  }
+
+}
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 5415)
+++ /trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding-3.3.csproj	(revision 5416)
@@ -126,4 +126,5 @@
     <Compile Include="Crossovers\CrossoverPoint.cs" />
     <Compile Include="Crossovers\SymbolicExpressionTreeCrossover.cs" />
+    <Compile Include="Formatters\SymbolicExpressionTreeStringFormatter.cs" />
     <Compile Include="Interfaces\ISymbolicExpressionTreeAnalyzer.cs" />
     <Compile Include="Interfaces\ISymbolicExpressionTreeArchitectureManipulator.cs" />
@@ -131,4 +132,5 @@
     <Compile Include="Interfaces\ISymbolicExpressionTreeCrossover.cs" />
     <Compile Include="Interfaces\ISymbolicExpressionTreeNode.cs" />
+    <Compile Include="Interfaces\ISymbolicExpressionTreeStringFormatter.cs" />
     <Compile Include="Manipulators\ChangeNodeTypeManipulation.cs" />
     <Compile Include="Interfaces\ISymbolicExpressionTreeManipulator.cs" />
@@ -139,5 +141,4 @@
     <Compile Include="Manipulators\SymbolicExpressionTreeManipulator.cs" />
     <Compile Include="SymbolicExpressionTreeGrammar.cs" />
-    <Compile Include="SymbolicExpressionTreeStringFormatter.cs" />
     <Compile Include="SymbolicExpressionTreeTopLevelNode.cs" />
     <Compile Include="Crossovers\SubtreeCrossover.cs">
Index: /trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/Interfaces/ISymbolicExpressionTreeStringFormatter.cs
===================================================================
--- /trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/Interfaces/ISymbolicExpressionTreeStringFormatter.cs	(revision 5416)
+++ /trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/Interfaces/ISymbolicExpressionTreeStringFormatter.cs	(revision 5416)
@@ -0,0 +1,29 @@
+﻿#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.Core;
+
+namespace HeuristicLab.Encodings.SymbolicExpressionTreeEncoding {
+  public interface ISymbolicExpressionTreeStringFormatter: INamedItem {
+    string Format(SymbolicExpressionTree symbolicExpressionTree);
+  }
+}
Index: unk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/SymbolicExpressionTreeStringFormatter.cs
===================================================================
--- /trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/SymbolicExpressionTreeStringFormatter.cs	(revision 5415)
+++ 	(revision )
@@ -1,62 +1,0 @@
-﻿#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;
-
-namespace HeuristicLab.Encodings.SymbolicExpressionTreeEncoding {
-  
-  public class SymbolicExpressionTreeStringFormatter {
-    
-    public bool Indent { get; set; }
-    
-    public SymbolicExpressionTreeStringFormatter()
-      : base() {
-      Indent = true;
-    }
-
-    public string Format(SymbolicExpressionTree symbolicExpressionTree) {
-      return FormatRecursively(symbolicExpressionTree.Root, 0);
-    }
-
-    private string FormatRecursively(SymbolicExpressionTreeNode node, int indentLength) {
-      StringBuilder strBuilder = new StringBuilder();
-      if (Indent) strBuilder.Append(' ', indentLength);
-      strBuilder.Append("(");
-      // internal nodes or leaf nodes?
-      if (node.SubTrees.Count > 0) {
-        // symbol on same line as '('
-        strBuilder.AppendLine(node.ToString());
-        // each subtree expression on a new line
-        // and closing ')' also on new line
-        foreach (var subtree in node.SubTrees) {
-          strBuilder.AppendLine(FormatRecursively(subtree, indentLength + 2));
-        }
-        if (Indent) strBuilder.Append(' ', indentLength);
-        strBuilder.Append(")");
-      } else {
-        // symbol in the same line with as '(' and ')'
-        strBuilder.Append(node.ToString());
-        strBuilder.Append(")");
-      }
-      return strBuilder.ToString();
-    }
-  }
-}
Index: /trunk/sources/HeuristicLab.Problems.ExternalEvaluation.GP/3.3/SymbolicExpressionTreeStringConverter.cs
===================================================================
--- /trunk/sources/HeuristicLab.Problems.ExternalEvaluation.GP/3.3/SymbolicExpressionTreeStringConverter.cs	(revision 5415)
+++ /trunk/sources/HeuristicLab.Problems.ExternalEvaluation.GP/3.3/SymbolicExpressionTreeStringConverter.cs	(revision 5416)
@@ -25,4 +25,5 @@
 using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
 using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
+using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding.Formatters;
 
 namespace HeuristicLab.Problems.ExternalEvaluation.GP {
