--- a/excel.py	Mon Jun 26 18:08:25 2017 +0100
+++ b/excel.py	Wed Jun 28 19:08:30 2017 +0100
@@ -1,11 +1,16 @@
 #!/usr/bin/python3
 '''Class model for analysis of Excel spreadsheets'''
 from jsonweb.encode import to_object, dumper
+from jsonweb.decode import from_object, loader
+import json
+import eDecoder
+
 try:
   string_types=basestring
 except NameError:
   string_types=str
 
+@from_object()
 @to_object(exclude_nulls=True)
 class Book(object):
   def __init__(self,source,sheets=[],formats=[]):
@@ -21,15 +26,14 @@
     assert(isinstance(sheet,Sheet))
     self.sheets.append(sheet)
 
+@from_object()
 @to_object(exclude_nulls=True,suppress=["book"])
 class Sheet(object):
-  def __init__(self,name,book,tables=[],docs=[],misc=[]):
+  def __init__(self,name,book=None,tables=[],docs=[],misc=[]):
     assert(isinstance(name,string_types))
     self.name=name
-    assert(isinstance(book,Book))
-    self.book=book
     tables=list(tables)
-    assert(all(isinstance(s,Region) for s in tables))
+    assert(all(isinstance(s,Table) for s in tables))
     self.tables=tables
     docs=list(docs)
     assert(all(isinstance(s,Region) for s in docs))
@@ -37,22 +41,68 @@
     misc=list(misc)
     assert(all(isinstance(s,Region) for s in misc))
     self.misc=misc
-    book.addSheet(self)
+    if book is not None:
+      assert(isinstance(book,Book))
+      book.addSheet(self)
+    self.book=book
 
   def addTable(self,table):
     assert(isinstance(table,Region))
     self.tables.append(table)
 
-@to_object(exclude_nulls=True,suppress=["sheet"])
+@from_object()
+@to_object(exclude_nulls=True,suppress=["parent"])
 class Region(object):
-  def __init__(self,name,sheet=None,ranges=[]):
-    if sheet is not None:
-      assert(isinstance(sheet,Sheet))
-    self.sheet=sheet
+  def __init__(self,name,parent=None,ranges=[],content=[]):
+    if parent is not None:
+      assert(isinstance(parent,(Region,Sheet)))
+    self.parent=parent
     ranges=list(ranges)
     assert(all(isinstance(s,Range) for s in ranges))
     self.ranges=ranges
+    content=list(content)
+    assert(all(isinstance(s,(Region,string_types)) for s in content))
+    self.content=content
     assert(isinstance(name,string_types))
     self.name=name
+    if parent is not None:
+      parent.addRegion(self)
+
+  def addRegion(self,content):
+    assert(isinstance(content,(Region,string_types)))
+    self.content.append(content)
+
+@from_object()
+@to_object(exclude_nulls=True,suppress=["sheet"])
+class Table(Region):
+  def __init__(self,name,sheet=None,ranges=[],labels=[],data=[]):
+    super(Table,self).__init__(name,sheet,ranges)
+    labels=list(labels)
+    assert(all(isinstance(s,Label) for s in labels))
+    self.labels=labels
+    data=list(data)
+    assert(all(isinstance(s,Region) for s in data))
+    self.data=data
     if sheet is not None:
+      assert(isinstance(sheet,Sheet))
       sheet.addTable(self)
+    self.sheet=sheet
+
+  def addLabel(self,label):
+    assert(isinstance(label,Label))
+    self.labels.append(label)
+
+  def addData(self,data):
+    assert(isinstance(data,Data))
+    self.data.append(data)
+
+  def addRegion(self,region):
+    assert(isinstance(region,(Label,Data)))
+    if isinstance(region,Label):
+      self.addLabel(region)
+    else:
+      self.addData(region)
+
+def lt(filename):
+  with open(filename,'r') as js:
+    return json.loads(js.read(),cls=eDecoder.eDecoder)