Add the equations defined by the function g to the definition of this
attribute after the existing definitions.
Remove the function g from the definitions of this attribute.
Remove the function g from the definitions of this attribute. If
g was not previously added to the definitions, do nothing.
Obtain the attribute value.
Obtain the attribute value.
Return the function defining this attribute as ComposedPartialFunction.
Return the function defining this attribute as ComposedPartialFunction.
Is the attribute defined at the node t?
Is the attribute defined at the node t?
Immediately reset this attribute's memoisation cache.
A dynamic atribute defined initially by the function
f.