Tuning ValueHolder as I could not find better option to generate the double-underscore methods.

bonobo/util/objects.py

@@ -1,3 +1,7 @@
+import functools
+from functools import partial
+
+
 def get_name(mixed):
     try:
         return mixed.__name__
@@ -27,181 +31,194 @@ class ValueHolder:
     
     """
 
-    def __init__(self, value, *, type=None):
-        self.value = value
-        self.type = type
+    def __init__(self, value):
+        self._value = value
 
-    def __repr__(self):
-        return repr(self.value)
+    @property
+    def value(self):
+        # XXX deprecated
+        return self._value
 
-    def __lt__(self, other):
-        return self.value < other
+    def get(self):
+        return self._value
 
-    def __le__(self, other):
-        return self.value <= other
+    def set(self, new_value):
+        self._value = new_value
+
+    def __bool__(self):
+        return bool(self._value)
 
     def __eq__(self, other):
-        return self.value == other
+        return self._value == other
 
     def __ne__(self, other):
-        return self.value != other
+        return self._value != other
+
+    def __repr__(self):
+        return repr(self._value)
+
+    def __lt__(self, other):
+        return self._value < other
+
+    def __le__(self, other):
+        return self._value <= other
 
     def __gt__(self, other):
-        return self.value > other
+        return self._value > other
 
     def __ge__(self, other):
-        return self.value >= other
+        return self._value >= other
 
     def __add__(self, other):
-        return self.value + other
+        return self._value + other
 
     def __radd__(self, other):
-        return other + self.value
+        return other + self._value
 
     def __iadd__(self, other):
-        self.value += other
+        self._value += other
         return self
 
     def __sub__(self, other):
-        return self.value - other
+        return self._value - other
 
     def __rsub__(self, other):
-        return other - self.value
+        return other - self._value
 
     def __isub__(self, other):
-        self.value -= other
+        self._value -= other
         return self
 
     def __mul__(self, other):
-        return self.value * other
+        return self._value * other
 
     def __rmul__(self, other):
-        return other * self.value
+        return other * self._value
 
     def __imul__(self, other):
-        self.value *= other
+        self._value *= other
         return self
 
     def __matmul__(self, other):
-        return self.value @ other
+        return self._value @ other
 
     def __rmatmul__(self, other):
-        return other @ self.value
+        return other @ self._value
 
     def __imatmul__(self, other):
-        self.value @= other
+        self._value @= other
         return self
 
     def __truediv__(self, other):
-        return self.value / other
+        return self._value / other
 
     def __rtruediv__(self, other):
-        return other / self.value
+        return other / self._value
 
     def __itruediv__(self, other):
-        self.value /= other
+        self._value /= other
         return self
 
     def __floordiv__(self, other):
-        return self.value // other
+        return self._value // other
 
     def __rfloordiv__(self, other):
-        return other // self.value
+        return other // self._value
 
     def __ifloordiv__(self, other):
-        self.value //= other
+        self._value //= other
         return self
 
     def __mod__(self, other):
-        return self.value % other
+        return self._value % other
 
     def __rmod__(self, other):
-        return other % self.value
+        return other % self._value
 
     def __imod__(self, other):
-        self.value %= other
+        self._value %= other
         return self
 
     def __divmod__(self, other):
-        return divmod(self.value, other)
+        return divmod(self._value, other)
 
     def __rdivmod__(self, other):
-        return divmod(other, self.value)
+        return divmod(other, self._value)
 
     def __pow__(self, other):
-        return self.value**other
+        return self._value**other
 
     def __rpow__(self, other):
-        return other**self.value
+        return other**self._value
 
     def __ipow__(self, other):
-        self.value **= other
+        self._value **= other
         return self
 
     def __lshift__(self, other):
-        return self.value << other
+        return self._value << other
 
     def __rlshift__(self, other):
-        return other << self.value
+        return other << self._value
 
     def __ilshift__(self, other):
-        self.value <<= other
+        self._value <<= other
         return self
 
     def __rshift__(self, other):
-        return self.value >> other
+        return self._value >> other
 
     def __rrshift__(self, other):
-        return other >> self.value
+        return other >> self._value
 
     def __irshift__(self, other):
-        self.value >>= other
+        self._value >>= other
         return self
 
     def __and__(self, other):
-        return self.value & other
+        return self._value & other
 
     def __rand__(self, other):
-        return other & self.value
+        return other & self._value
 
     def __iand__(self, other):
-        self.value &= other
+        self._value &= other
         return self
 
     def __xor__(self, other):
-        return self.value ^ other
+        return self._value ^ other
 
     def __rxor__(self, other):
-        return other ^ self.value
+        return other ^ self._value
 
     def __ixor__(self, other):
-        self.value ^= other
+        self._value ^= other
         return self
 
     def __or__(self, other):
-        return self.value | other
+        return self._value | other
 
     def __ror__(self, other):
-        return other | self.value
+        return other | self._value
 
     def __ior__(self, other):
-        self.value |= other
+        self._value |= other
         return self
 
     def __neg__(self):
-        return -self.value
+        return -self._value
 
     def __pos__(self):
-        return +self.value
+        return +self._value
 
     def __abs__(self):
-        return abs(self.value)
+        return abs(self._value)
 
     def __invert__(self):
-        return ~self.value
+        return ~self._value
 
     def __len__(self):
-        return len(self.value)
+        return len(self._value)
 
 
 def get_attribute_or_create(obj, attr, default):