diff --git a/lib/salama-object-file.rb b/lib/salama-object-file.rb
index d805ad9..1234380 100644
--- a/lib/salama-object-file.rb
+++ b/lib/salama-object-file.rb
@@ -1,3 +1,7 @@
+# Most of the external functionality is in the writer
+
+# if you want some attributes not written also check volotile
+
 require_relative "sof/util"
 require_relative "sof/node"
 require_relative "sof/simple_node"
diff --git a/lib/sof/array.rb b/lib/sof/array.rb
index b9ef85b..935cd36 100644
--- a/lib/sof/array.rb
+++ b/lib/sof/array.rb
@@ -1,13 +1,39 @@
+# If a class defines to_sof_node it tells the write that it will generate Nodes itself
+# this delegates to array_to_sof_node
+Array.class_eval do
+  def to_sof_node(writer , level , ref )
+    Sof.array_to_sof_node(self , writer , level , ref )
+  end
+end
+
 module Sof
+  # Creates a ArrayNode (see there) for the Array.
+  # This mainly involves creating nodes for the children
+  def self.array_to_sof_node(array , writer , level , ref )
+    node = Sof::ArrayNode.new(ref)
+    array.each do |object|
+      node.add writer.to_sof_node( object , level + 1)
+    end
+    node
+  end
+
+  # A ArrayNode is a Node for a Array. See Node for when and how nodes are used in Sof.
+  # A ArrayNode has a list of children that hold the value node representations for
+  # the arrays values.
+  #
   class ArrayNode < Node
     def initialize ref
       super(ref)
       @children = []
     end
     attr_reader  :children
+
     def add c
       @children << c
     end
+
+    # The output of a Array can be a long or a short format
+    # The short is used for 7 or less SimpleNodes
     def out io , level = 0
       super
       short = true
@@ -22,6 +48,8 @@ module Sof
     end
 
     private
+    # This defines the short output which is basically what you would write in ruby
+    # ie [ value1 , value2 , ...]
     def short_out(io,level)
       io.write("[")
       @children.each_with_index do |child , i|
@@ -30,6 +58,9 @@ module Sof
       end
       io.write("]")
     end
+
+    # Arrays start with the minus on each line "-"
+    # and each line has the value
     def long_out io , level
       indent = " " * level
       @children.each_with_index do |child , i|
@@ -39,18 +70,4 @@ module Sof
       end
     end
   end
-
-  def self.array_to_sof_node(array , writer , level , ref )
-    node = Sof::ArrayNode.new(ref)
-    array.each do |object|
-      node.add writer.to_sof_node( object , level + 1)
-    end
-    node
-  end
-
-end
-Array.class_eval do
-  def to_sof_node(writer , level , ref )
-    Sof.array_to_sof_node(self , writer , level , ref )
-  end
 end
diff --git a/lib/sof/hash.rb b/lib/sof/hash.rb
index 6b1e725..a52fe05 100644
--- a/lib/sof/hash.rb
+++ b/lib/sof/hash.rb
@@ -1,13 +1,41 @@
+Hash.class_eval do
+  # If a class defines to_sof_node it tells the write that it will generate Nodes itself
+  # this delegates to hash_to_sof_node
+  def to_sof_node(writer , level , ref)
+    Sof.hash_to_sof_node( self , writer , level , ref)
+  end
+end
+
 module Sof
+  # Creates a HashNode (see there) for the Hash.
+  # This mainly involves creating nodes for key value pairs
+  def self.hash_to_sof_node(hash,writer , level , ref)
+    node = Sof::HashNode.new(ref)
+    hash.each do |key , object|
+      k = writer.to_sof_node( key ,level + 1)
+      v = writer.to_sof_node( object ,level + 1)
+      node.add(k , v)
+    end
+    node
+  end
+
+  # A HashNode is a Node for a Hash. See Node for when and how nodes are used in Sof.
+  # A HashNode has a list of children that hold the key/value node representations for
+  # the hashes keys and values.
+
   class HashNode < Node
     def initialize ref
       super(ref)
       @children = []
     end
     attr_reader  :children
+
     def add key , val
       @children << [key,val]
     end
+
+    # The output of a Hash can be a long or a short format
+    # The short is used for 7 or less SimpleNodes
     def out io , level = 0
       super
       short = true
@@ -21,6 +49,10 @@ module Sof
         long_out(io , level)
       end
     end
+
+    private
+    # This defines the short output which is basically what you would write in ruby
+    # ie { key1 => value1 , ... }
     def short_out(io,level)
       io.write("{")
       children.each_with_index do |child , i|
@@ -32,6 +64,10 @@ module Sof
       end
       io.write("}")
     end
+
+    # The long output is like an array of associations.
+    # Arrays start with the minus on each line "-"
+    # and each line has the association key => value, same as used for the {} syntax
     def long_out io , level
       indent = " " * level
       children.each_with_index do |child , i|
@@ -44,20 +80,4 @@ module Sof
       end
     end
   end
-
-  def self.hash_to_sof_node(hash,writer , level , ref)
-    node = Sof::HashNode.new(ref)
-    hash.each do |key , object|
-      k = writer.to_sof_node( key ,level + 1)
-      v = writer.to_sof_node( object ,level + 1)
-      node.add(k , v)
-    end
-    node
-  end
-end
-
-Hash.class_eval do
-  def to_sof_node(writer , level , ref)
-    Sof.hash_to_sof_node( self , writer , level , ref)
-  end
 end
diff --git a/lib/sof/members.rb b/lib/sof/members.rb
index 13e5c30..16a4fb4 100644
--- a/lib/sof/members.rb
+++ b/lib/sof/members.rb
@@ -1,24 +1,40 @@
 module Sof
-  
+
+  # Members are members of the graph to be written
+  # The class collects all reachable objects into a hash for further transformation
+
   class Members
     include Util
-    
+
+    # initialize with the "root" object
+    # any object really that then becomes the root.
+    # the result is easier to read if it really is a root
+    # All reachable objects are collected into "objects" hash
+    # The class keeps a counter for references encountered and creates unique
+    # occurences for each object based on object_id (not == or ===)
     def initialize root
       @root = root
       @counter = 1
       @objects = {}
-      @referenced = false
       add(root , 0)
     end
-    attr_reader :objects , :root , :referenced
-    
+    attr_reader :objects , :root
+
+    private
+    # recursively add reachable objects from this object
+    # this is called from the initialize and is private
     def add object , level
+      # not storing simple (value) objects
       return if is_value?(object)
+
+      # see if we we came accross this before
       if( occurence = @objects[object.object_id] )
         #puts "reset level #{level} at #{occurence.level}"
         if occurence.level > level
-          occurence.level = level 
+          #always store the most shallow level
+          occurence.level = level
         end
+        # and only one Occurence for each object, create a reference for the second occurence
         unless occurence.referenced
           #puts "referencing #{@counter} , at level #{level}/#{occurence.level} "
           occurence.set_reference(@counter)
@@ -26,18 +42,24 @@ module Sof
         end
         return
       end
+
+      # if first time see, create and store Occurence
       o = Occurence.new( object , level )
       @objects[object.object_id] = o
+
+      # and recursively add attributes
       attributes = attributes_for(object)
       attributes.each do |a|
         val = get_value( object , a)
         add(val , level + 1)
       end
+      # and array values
       if( object.is_a? Array )
         object.each do |a|
           add(a , level + 1)
         end
       end
+      # and hash keys/values
       if( object.is_a? Hash )
         object.each do |a,b|
           add(a , level + 1)
@@ -46,4 +68,6 @@ module Sof
       end
     end
   end
+  # TODO, since this class only has one function, and one instance
+  #  it could be merged as class functions to Occurence
 end
diff --git a/lib/sof/node.rb b/lib/sof/node.rb
index c706be0..0f745cf 100644
--- a/lib/sof/node.rb
+++ b/lib/sof/node.rb
@@ -1,22 +1,37 @@
 # We transform objects into a tree of nodes
 
 module Sof
-  # abstract base class for nodes in the tree
-  # may be referenced (should be a simple name or number)
+
+  # Before writing the objects are transformed into a tree of nodes.
+  # as the Members (all objects) are a graph (not tree) this is achieved by referencing
+  #
+  # There are only two subclasses, SimpleNode and ObejctNode, for simple or not
+  # The base class only holds the referenced flag
+  # Also nodes must implement the out function
+
   class Node
     include Util
+    # only has one attribute, the referenced flag
+    # This could be anything, but we use a simple number counter which is handled in the Members
+    #   class during construction of the occurrence hash
     def initialize ref
+      #puts "node has ref #{self.class}:#{ref}" if ref
       @referenced = ref
     end
+    attr_reader :referenced
+
     # must be able to output to a stream
+    # This function must be called as super as it handles possible reference marker "& num"
     def out io ,level
       io.write "&#{@referenced} " if @referenced
     end
+
+    # helper function to return the output as a string
+    # ie creates stringio, calls out and returns the string
     def as_string(level)
       io = StringIO.new
       out(io,level)
       io.string
     end
-    attr_reader :referenced
   end
 end
diff --git a/lib/sof/object_node.rb b/lib/sof/object_node.rb
index 0b5c2da..f1c7e9a 100644
--- a/lib/sof/object_node.rb
+++ b/lib/sof/object_node.rb
@@ -2,18 +2,27 @@
 module Sof
 
   # ObjectNode means node with structure
-  # ie arrays and hashes get transformed into these too
+  # ie arrays and hashes get transformed into these too, as well as objects with attributes
 
   class ObjectNode < Node
+
+    # init with a string, much like a simple node
+    # structure is added after construction and kept in a children array
     def initialize data , ref
       super(ref)
       @data = data
       @children = []
     end
     attr_reader   :children ,  :data
+
+    # children array hold key value pairs
     def add k , v
       @children << [k,v]
     end
+
+    # write out at the given level
+    # level determines the indentation (level * space)
+    # write out the data and then the children (always key value on one line) 
     def out io , level = 0
       super
       io.write(@data)
diff --git a/lib/sof/occurence.rb b/lib/sof/occurence.rb
index 225cde9..c208e36 100644
--- a/lib/sof/occurence.rb
+++ b/lib/sof/occurence.rb
@@ -1,5 +1,9 @@
 module Sof
 
+  # simple struct like class to wrap an object and hold additionally
+  #  - the shallowest level at which it was seen
+  #  - A possible reference
+  #  - the fact if it has been written (for referenced objects)
   class Occurence
     def initialize object , level
       @object = object
diff --git a/lib/sof/simple_node.rb b/lib/sof/simple_node.rb
index acc43bc..b915503 100644
--- a/lib/sof/simple_node.rb
+++ b/lib/sof/simple_node.rb
@@ -1,19 +1,25 @@
-# We transform objects into a tree of nodes
-
 module Sof
 
   # What makes a node simple is that it has no further structure
   #
+  # This may mean number/string/symbol, but also tiny arrays or objects with
+  # very little attributes. In other words simple/object is not the same distinction
+  # as value/not value
+
   class SimpleNode < Node
+
+    # data is a string that is written out in "out" function
     def initialize data , ref = nil
       super(ref)
       @data = data
     end
     attr_reader :data
+
+    # just write the data given in construcor. simple. hence the name.
     def out io , level
       super(io,level)
       io.write(data)
     end
   end
-  
+
 end
diff --git a/lib/sof/util.rb b/lib/sof/util.rb
index abd9367..4cd5dfe 100644
--- a/lib/sof/util.rb
+++ b/lib/sof/util.rb
@@ -1,5 +1,10 @@
 module Sof
+
+  # module for a couple of helpers that are needed in Members and Writer
+
   module Util
+    # "value" is a property meaning simple/ not further structure
+    # hence int/bool/string etc are values
     def is_value? o
       return true if [true , false ,  nil].include?(o)
       return true if [Fixnum, Symbol, String].include?(o.class)
@@ -9,13 +14,22 @@ module Sof
       return false
     end
 
+    # extract an attribute by the given name from the object
+    # done with instance_variable_get
     def get_value(object,name)
       object.instance_variable_get "@#{name}".to_sym
     end
 
+    # return a list of attributes for a given object
+    # attributes may be supressed with Volotile
+    # TODO should be able to specify order too
     def attributes_for object
       Sof::Util.attributes(object)
     end
+
+    # return a list of attributes for a given object
+    # attributes may be supressed with Volotile
+    # TODO should be able to specify order too
     def self.attributes( object )
       atts = object.instance_variables.collect{|i| i.to_s[1..-1].to_sym } # chop of @
       atts - Volotile.attributes(object.class)
diff --git a/lib/sof/volotile.rb b/lib/sof/volotile.rb
index 704a9f8..7226f20 100644
--- a/lib/sof/volotile.rb
+++ b/lib/sof/volotile.rb
@@ -1,11 +1,27 @@
 module Sof
-  class Volotile
+
+  # Volotile module keeps track of attributes that are not menat to be written
+  # The idea being similar to private methods. So not every little detail is relevant
+  # for the object. Some attribuets may be calculated, cached etc,
+  #
+  # There is only one useful call for the user, "add" attributes for a given class
+  #
+  module Volotile
     @@mapping = {    }
-    def self.attributes clazz
-      @@mapping[clazz] || []
-    end
+
+    # Add attributes that are then ommited from the sof writing process
+    # The clazz is the real class object (eg String), and thus the
+    # adding must happen after the class definition, often at the end of the file
+    # attributes are an array of Symbols
     def self.add clazz , attributes
       @@mapping[clazz] = attributes
     end
+
+    private
+    # return the volotile attributes as an array (or empty array)
+    def self.attributes clazz
+      @@mapping[clazz] || []
+    end
+
   end
 end
diff --git a/lib/sof/writer.rb b/lib/sof/writer.rb
index beb82ff..484f2ca 100644
--- a/lib/sof/writer.rb
+++ b/lib/sof/writer.rb
@@ -1,10 +1,29 @@
 module Sof
+
+  # this function writes the object (and all reachable objects) out as sof
+  # and returns a string
+  # For trees or graphs this works best by handing roots
+  # Internally this is done in three steps:
+  # - All reachable objects are collected, these are called Occurences and the Members class does
+  #     the collecting. Members holds a hash of occurences
+  # - A tree of nodes is created from the occurences. Different node classes for different classes
+  # - The nodes are witten to a steam
+  def self.write object
+    writer = Writer.new(Members.new(object) )
+    writer.write
+  end
+
+  # The writer does the coordinating work of the stages (see write function)
   class Writer
     include Util
+
+    # Initialized with the Members (hash of occurences, see there)
     def initialize members
       @members = members
     end
 
+    # main function, creates nodes from the occurences and writes the nodes to a string
+    # returns the sof formatted string for all objects
     def write
       node = to_sof_node(@members.root , 0)
       io = StringIO.new
@@ -12,6 +31,12 @@ module Sof
       io.string
     end
 
+    # create a Node (subclass) for an object at a given level.
+    # Level is mainly needed for the indenting
+    # from the object we get the Occurence and decide wether a reference node is needed
+    # simple objects (with more inner structure) become SimpleNodes
+    # Any structured object bocomes a ObjectNode
+    # Hash and Array create their own nodes via  to_sof_node functions on the classes
     def to_sof_node(object , level)
       if is_value?(object)
         return SimpleNode.new(object.to_sof())
@@ -35,6 +60,10 @@ module Sof
       end
     end
 
+    # create an object node from the object
+    # simple nodes are returned for small objects
+    #   small means only simple attributes and only 30 chars of them
+    # object nodes are basically arrays (see there)
     def object_sof_node( object , level , ref)
       if( object.is_a? Class )
         return SimpleNode.new( object.name , ref )
@@ -55,11 +84,5 @@ module Sof
       end
       node
     end
-
-    def self.write object
-      writer = Writer.new(Members.new(object) )
-      writer.write
-    end
-
   end
 end
diff --git a/test/helper.rb b/test/helper.rb
index 359dfa0..83bb5ea 100644
--- a/test/helper.rb
+++ b/test/helper.rb
@@ -17,7 +17,7 @@ require 'salama-object-file'
 
 module Checker
   def check should
-    out = Sof::Writer.write(@out)
+    out = Sof.write(@out)
     same = (should == out)
     puts "Shouldda\n#{out}" unless same
     assert_equal should , out