Opt.FlagsSourceval grammar_extension :
(unit, Libparser.obj, unit, unit, Libparser.obj Dyp.dyplexbuf) Dyp.dyp_action
listval extension :
(module Types.EXPLORATION_STATISTICS) ->
(module Path.S with type t = 'a) ->
(module Types.STATE with type t = 'b) ->
(module Exec.EXTENSION with type path = 'a and type state = 'b) option