Pprintast

`sig
type space_formatter = (unit, Stdlib.Format.formatter, unit) Stdlib.format
val longident : Stdlib.Format.formatter -> Longident.t -> unit
val expression : Stdlib.Format.formatter -> Parsetree.expression -> unit
val string_of_expression : Parsetree.expression -> string
val pattern : Stdlib.Format.formatter -> Parsetree.pattern -> unit
val core_type : Stdlib.Format.formatter -> Parsetree.core_type -> unit
val signature : Stdlib.Format.formatter -> Parsetree.signature -> unit
val structure : Stdlib.Format.formatter -> Parsetree.structure -> unit
val string_of_structure : Parsetree.structure -> string
val toplevel_phrase :
Stdlib.Format.formatter -> Parsetree.toplevel_phrase -> unit
val top_phrase :
Stdlib.Format.formatter -> Parsetree.toplevel_phrase -> unit
val tyvar : Stdlib.Format.formatter -> string -> unit
end`