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  1. Backtrackable ref
package msat
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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.