Re: why format procedure produce error?

[Neil Jerram <neil@ossau.uklinux.net>]

Changying Li <lchangying@gmail.com> writes:

> in the guile manual:
>  -- Scheme Procedure: format dest fmt [args...]
>      Write output specified by the FMT string to DEST.  DEST can be an
>      output port, `#t' for `current-output-port' (*note Default
>      Ports::), a number for `current-error-port', or `#f' to return the
>      output as a string.
>
> what's the meaning of NUMBER?
> I want to write things to error port, so I write
> (format 1 "hello")
>
> standard input:5:1: In procedure simple-format in expression (format 1 "hello"):
> standard input:5:1: Wrong type argument in position 1: 1
> ABORT: (wrong-type-arg)

You need to add (use-modules (ice-9 format)) to your code, to get the
full implementation of `format'.  Then the "number means
current-error-port" thing should work.

At the moment, you're actually using `simple-format'.

> Is there something wrong in the guile manual ?

I don't think so, because the documentation that you cited comes from a
section that begins by saying that

   "This function is available from

     (use-modules (ice-9 format))"

Regards,
        Neil