Demo for custom 'read' function and versioning of torch objects.

torch_obj_versioning.lua

--
local Foo, parent = torch.class('Foo')
Foo.__version = 1

function Foo:__init()
  parent.__init(self)
end

-- serialize 'old' object
old = Foo.new()
s = torch.serialize(old)

-- simulate addition of 'newField':
Foo.__version = 2  -- only to show how to specify a version (which is serialized with the obj)

function Foo:__init()
  parent.__init(self)
  self.newField = 101
end

function Foo:restore(version)
  self.newField = self.newField or 101
end

function Foo.read(obj, file, version)
  local var = file:readObject()
  for k,v in pairs(var) do
     obj[k] = v
  end
  obj:restore(version)
  return obj
end

-- deserialize old obj and check upgrade done by restored()
restored = torch.deserialize(s)
print(restored.newField)