Make.2-U
A unifier maintains a graph whose vertices are equivalence classes of variables. With each equivalence class, a piece of information of type data
is attached.
type 'a structure = 'a S.structure
The type 'a structure
describes the information that is attached with each class. It is parameterized over a type 'a
of children. In the definition of the type data
, 'a
is instantiated with variable
.
By definition, data
is a synonym for variable structure
. So, the data attached with an equivalence class of variables is a structure whose children are variables.