Adding documentation functionality on the nodes.

public virtual string documentationURL()   has been added to AbstractMaterialNode
Pressing F1 will take you to the documentation if it exists.
Right clicking on a node gives you the context menu item See Documentation that also takes you to the documentation if it exists.

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/AbstractMaterialNode.cs

             set { m_Name = value; }
         }
 
+        public virtual string documentationURL
+        {
+            get { return null; }
+        }
+
         public virtual bool canDeleteNode
         {
             get { return true; }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Math/Advanced/AbsoluteNode.cs

             name = "Absolute";
         }
 
+        public override string documentationURL
+        {
+            get { return "https://github.com/Unity-Technologies/ShaderGraph/wiki/Absolute-Node"; }
+        }
+
         protected override MethodInfo GetFunctionToConvert()
         {
             return GetType().GetMethod("Unity_Absolute", BindingFlags.Static | BindingFlags.NonPublic);

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Math/Advanced/ExponentialNode.cs

             name = "Exponential";
         }
 
+        public override string documentationURL
+        {
+            get { return "https://github.com/Unity-Technologies/ShaderGraph/wiki/Exponential-Node"; }
+        }
+
         [SerializeField]
         private ExponentialBase m_ExponentialBase = ExponentialBase.BaseE;
 

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Math/Advanced/LengthNode.cs

             name = "Length";
         }
 
+        public override string documentationURL
+        {
+            get { return "https://github.com/Unity-Technologies/ShaderGraph/wiki/Length-Node"; }
+        }
+
         protected override MethodInfo GetFunctionToConvert()
         {
             return GetType().GetMethod("Unity_Length", BindingFlags.Static | BindingFlags.NonPublic);

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Math/Advanced/LogNode.cs

             name = "Log";
         }
 
+        public override string documentationURL
+        {
+            get { return "https://github.com/Unity-Technologies/ShaderGraph/wiki/Log-Node"; }
+        }
+
         [SerializeField]
         private LogBase m_LogBase = LogBase.BaseE;
 

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Math/Advanced/ModuloNode.cs

             name = "Modulo";
         }
 
+        public override string documentationURL
+        {
+            get { return "https://github.com/Unity-Technologies/ShaderGraph/wiki/Modulo-Node"; }
+        }
+
         protected override MethodInfo GetFunctionToConvert()
         {
             return GetType().GetMethod("Unity_Modulo", BindingFlags.Static | BindingFlags.NonPublic);

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Math/Advanced/NegateNode.cs

             name = "Negate";
         }
 
+        public override string documentationURL
+        {
+            get { return "https://github.com/Unity-Technologies/ShaderGraph/wiki/Negate-Node"; }
+        }
+
         protected override MethodInfo GetFunctionToConvert()
         {
             return GetType().GetMethod("Unity_Negate", BindingFlags.Static | BindingFlags.NonPublic);

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Math/Advanced/NormalizeNode.cs

             name = "Normalize";
         }
 
+        public override string documentationURL
+        {
+            get { return "https://github.com/Unity-Technologies/ShaderGraph/wiki/Normalize-Node"; }
+        }
+
         protected override MethodInfo GetFunctionToConvert()
         {
             return GetType().GetMethod("Unity_Normalize", BindingFlags.Static | BindingFlags.NonPublic);

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Math/Advanced/PosterizeNode.cs

             name = "Posterize";
         }
 
+        public override string documentationURL
+        {
+            get { return "https://github.com/Unity-Technologies/ShaderGraph/wiki/Posterize-Node"; }
+        }
+
         protected override MethodInfo GetFunctionToConvert()
         {
             return GetType().GetMethod("Unity_Posterize", BindingFlags.Static | BindingFlags.NonPublic);

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Math/Advanced/ReciprocalNode.cs

             name = "Reciprocal";
         }
 
+        public override string documentationURL
+        {
+            get { return "https://github.com/Unity-Technologies/ShaderGraph/wiki/Reciprocal-Node"; }
+        }
+
         [SerializeField]
         private ReciprocalMethod m_ReciprocalMethod = ReciprocalMethod.Default;
 

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Math/Advanced/ReciprocalSquareRootNode.cs

             name = "Reciprocal Square Root";
         }
 
+        public override string documentationURL
+        {
+            get { return "https://github.com/Unity-Technologies/ShaderGraph/wiki/Reciprocal-Square-Root-Node"; }
+        }
+
         protected override MethodInfo GetFunctionToConvert()
         {
             return GetType().GetMethod("Unity_Rsqrt", BindingFlags.Static | BindingFlags.NonPublic);

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Math/Basic/AddNode.cs

             name = "Add";
         }
 
+        public override string documentationURL
+        {
+            get { return "https://github.com/Unity-Technologies/ShaderGraph/wiki/Add-Node"; }
+        }
+
         protected override MethodInfo GetFunctionToConvert()
         {
             return GetType().GetMethod("Unity_Add", BindingFlags.Static | BindingFlags.NonPublic);

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Math/Basic/DivideNode.cs

             name = "Divide";
         }
 
+        public override string documentationURL
+        {
+            get { return "https://github.com/Unity-Technologies/ShaderGraph/wiki/Divide-Node"; }
+        }
+
         protected override MethodInfo GetFunctionToConvert()
         {
             return GetType().GetMethod("Unity_Divide", BindingFlags.Static | BindingFlags.NonPublic);

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Math/Basic/MultiplyNode.cs

             name = "Multiply";
         }
 
+        public override string documentationURL
+        {
+            get { return "https://github.com/Unity-Technologies/ShaderGraph/wiki/Multiply-Node"; }
+        }
+
         protected override MethodInfo GetFunctionToConvert()
         {
             return GetType().GetMethod("Unity_Multiply", BindingFlags.Static | BindingFlags.NonPublic);

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Math/Basic/PowerNode.cs

             name = "Power";
         }
 
+        public override string documentationURL
+        {
+            get { return "https://github.com/Unity-Technologies/ShaderGraph/wiki/Power-Node"; }
+        }
+
         protected override MethodInfo GetFunctionToConvert()
         {
             return GetType().GetMethod("Unity_Power", BindingFlags.Static | BindingFlags.NonPublic);

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Math/Basic/SquareRootNode.cs

             name = "Square Root";
         }
 
+        public override string documentationURL
+        {
+            get { return "https://github.com/Unity-Technologies/ShaderGraph/wiki/Square-Root-Node"; }
+        }
+
         protected override MethodInfo GetFunctionToConvert()
         {
             return GetType().GetMethod("Unity_SquareRoot", BindingFlags.Static | BindingFlags.NonPublic);

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Math/Basic/SubtractNode.cs

             name = "Subtract";
         }
 
+        public override string documentationURL
+        {
+            get { return "https://github.com/Unity-Technologies/ShaderGraph/wiki/Subtract-Node"; }
+        }
+
         protected override MethodInfo GetFunctionToConvert()
         {
             return GetType().GetMethod("Unity_Subtract", BindingFlags.Static | BindingFlags.NonPublic);

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Views/GraphEditorView.cs

         string m_FloatingWindowsLayoutKey;
         FloatingWindowsLayout m_FloatingWindowsLayout;
 
+        string m_DocumentURL = "https://github.com/Unity-Technologies/ShaderGraph/wiki";
         public Action saveRequested { get; set; }
 
         public Action convertToSubgraphRequested
                 Vector2 screenPoint = m_EditorWindow.position.position + referencePosition;
 
                 graphView.nodeCreationRequest(new NodeCreationContext() { screenMousePosition = screenPoint });
+            }
+            else if (evt.keyCode == KeyCode.F1)
+            {
+                if (m_GraphView.selection.OfType<MaterialNodeView>().Count() == 1)
+                {
+                    var nodeView = (MaterialNodeView)graphView.selection.First();
+                    if(nodeView.node.documentationURL != null)
+                        System.Diagnostics.Process.Start(nodeView.node.documentationURL);
+                    else
+                        Debug.Log("Missing Documentation URL for -> " + System.Diagnostics.Process.Start(m_DocumentURL));
+                }
             }
         }
 

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Views/MaterialGraphView.cs

         public AbstractMaterialGraph graph { get; private set; }
         public Action onConvertToSubgraphClick { get; set; }
 
+        private string m_DocumentURL = "https://github.com/Unity-Technologies/ShaderGraph/wiki";
+
         public override List<Port> GetCompatiblePorts(Port startAnchor, NodeAdapter nodeAdapter)
         {
             var compatibleAnchors = new List<Port>();
                 evt.menu.AppendAction("Convert To Sub-graph", ConvertToSubgraph, ConvertToSubgraphStatus);
                 evt.menu.AppendAction("Convert To Inline Node", ConvertToInlineNode, ConvertToInlineNodeStatus);
                 evt.menu.AppendAction("Convert To Property", ConvertToProperty, ConvertToPropertyStatus);
+                evt.menu.AppendSeparator();
+                evt.menu.AppendAction("See Documentation", SeeDocumentation, SeeDocumentationStatus);
+        }
+
+        void SeeDocumentation(EventBase evt)
+        {
+            var node = selection.OfType<MaterialNodeView>().First().node;
+            if (node.documentationURL != null)
+                System.Diagnostics.Process.Start(node.documentationURL);
+            else
+                Debug.Log("Missing Documentation URL for -> " + System.Diagnostics.Process.Start(m_DocumentURL));
+        }
+
+        ContextualMenu.MenuAction.StatusFlags SeeDocumentationStatus(EventBase eventBase)
+        {
+            if (selection.OfType<MaterialNodeView>().Count() > 1)
+                return ContextualMenu.MenuAction.StatusFlags.Hidden;
+            return ContextualMenu.MenuAction.StatusFlags.Normal;
         }
 
         ContextualMenu.MenuAction.StatusFlags ConvertToPropertyStatus(EventBase eventBase)