module type S = sig .. end
type
type
type
A state consists of a partition of the items (or, in other words,
of an equivalence relation over items), together with a total
mapping of the partition blocks (or, in other words, of the
equivalence classes) to descriptors.
type
In the initial state, each item forms its own block, and each
block is mapped to the default descriptor.
val initial : state
representative maps each item to a representative member of its
block.
val representative : item -> state -> item
equivalent tells whether two items are members of the same
block.
val equivalent : item -> item -> state -> bool
descriptor maps (items to) blocks to descriptors.
val descriptor : item -> state -> descriptor
set changes the descriptor associated with a block.
val set : item ->
descriptor -> state -> state
union merges two blocks. The new block's descriptor is obtained
as the union of the two original descriptors. Computing the union
of two descriptors can have side effects, reflected via the
accumulator monad.
val union : item ->
item ->
state ->
accumulator -> state * accumulator
val domain : state -> item list