Provide primitives for manipulating file path structures in the underlying OS IO.

signature OS_PATH =
sig
  exception InvalidArc
  exception Path
  val base : string -> string
  val concat : string * string -> string
  val currentArc : string
  val dir : string -> string
  val ext : string -> string option
  val file : string -> string
  val fromString : string -> {isAbs : bool, vol : string, arcs : string list}
  val fromUnixPath : string -> string
  val getParent : string -> string
  val getVolume : string -> string
  val isAbsolute : string -> bool
  val isCanonical : string -> bool
  val isRelative : string -> bool
  val isRoot : string -> bool
  val joinBaseExt : {base : string, ext : string option} -> string
  val joinDirFile : {dir : string, file : string} -> string
  val mkAbsolute : {path : string, relativeTo : string} -> string
  val mkCanonical : string -> string
  val mkRelative : {path : string, relativeTo : string} -> string
  val parentArc : string
  val splitBaseExt : string -> {base : string, ext : string option}
  val splitDirFile : string -> {dir : string, file : string}
  val toString : {isAbs : bool, vol : string, arcs : string list} -> string
  val toUnixPath : string -> string
  val validVolume : {isAbs : bool, vol : string} -> bool
end