Selective (preface.Preface

module type LAWS = sig ... end

module type LAWS_RIGID = sig ... end

module For (S : Preface_specs.SELECTIVE) : LAWS with type 'a t := 'a S.t

module For_rigid
  (S : Preface_specs.SELECTIVE) : 
  LAWS_RIGID with type 'a t := 'a S.t