Sourceval (^=!) : ('a, 'b) t -> 'b -> 'a -> unit * 'a Pseudo-imperatives
Sourceval (+=!) : ('a, int) t -> int -> 'a -> unit * 'a Sourceval (-=!) : ('a, int) t -> int -> 'a -> unit * 'a Sourceval (@=!) : ('a, 'b list) t -> 'b list -> 'a -> unit * 'a