external string_of_sv : sv -> string = "perl4caml_string_of_sv"
external sv_of_string : string -> sv = "perl4caml_sv_of_string"
external sv_is_true : sv -> bool = "perl4caml_sv_is_true"
external string_of_sv : sv -> string = "perl4caml_string_of_sv"
external sv_of_string : string -> sv = "perl4caml_sv_of_string"
external sv_is_true : sv -> bool = "perl4caml_sv_is_true"