> Right.  The Guile printer has no option of that sort yet.  Quickly I
> would think that this should work:
>
> (use-modules (oop goops))
>
> (define-method (display (bv <bytevector>) port)
>   (format port "#vu8(~{#x~x~})" (bytevector->u8-list bv)))
>
> but I haven't tested it.

Thanks for your help!

I test your code in repl but it looks that procedure "display" is still not
a generic function. If I test `(format port ....)` independently, it
works well.

Anyway, thanks a lot :)

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Zihao