sig
val ( // ) : string -> string -> string
val env : string -> string option
val failwithf : ('a, unit, string, 'b) Pervasives.format4 -> 'a
val succeed : string -> unit
val succeedf : ('a, unit, string, unit) Pervasives.format4 -> 'a
val all_files : string -> string list
val read_file : string -> string
val write_file : string -> content:string -> unit
val parse_list_of_substitutions : string -> (string * string) list
end