Module `Msat_backtrack__.Backtrackable_ref`

Backtrackable ref

type 'a t

val create : ?⁠copy:('a -> 'a) -> 'a -> 'a t

Create a backtrackable reference holding the given value initially.

parameter copy: if provided, will be used to copy the value when push_level is called.

val set : 'a t -> 'a -> unit: Set the reference's current content

val get : 'a t -> 'a: Get the reference's current content

val update : 'a t -> ('a -> 'a) -> unit: Update the reference's current content

val push_level : _ t -> unit: Push a backtracking level, copying the current value on top of some stack. The copy function will be used if it was provided in create.

val n_levels : _ t -> int: Number of saved values

val pop_levels : _ t -> int -> unit

Pop n levels, restoring to the value the reference was storing n calls to push_level earlier.

raises Invalid_argument: if n is bigger than n_levels.