val option' :
(Stdlib.Format.formatter -> 'a -> unit) ->
Stdlib.Format.formatter ->
'a option ->
unitval via : Stdlib.Format.formatter -> via -> unitval sign : Stdlib.Format.formatter -> sign -> unitval _sig_via : Stdlib.Format.formatter -> (sign * via option) -> unitval body : Stdlib.Format.formatter -> body -> unitval body' : Stdlib.Format.formatter -> body -> unitval message : Stdlib.Format.formatter -> t -> unitval message_short : Stdlib.Format.formatter -> t -> unit