From mboxrd@z Thu Jan  1 00:00:00 1970
From: Keisuke Nishida <kxn30@po.cwru.edu>
To: Kalle Olavi Niemitalo <tosi@ees2.oulu.fi>
Cc: guile-emacs@sourceware.cygnus.com
Subject: Re: New module (emacs io)
Date: Mon, 27 Mar 2000 17:48:00 -0000
Message-id: <m3hfdrdfvy.fsf@kei.cwru.edu>
References: <87ln3agfsl.fsf@PC486.Niemitalo.LAN> <m3g0tdblek.fsf@kei.cwru.edu> <87k8ioxysi.fsf@PC486.Niemitalo.LAN>
X-SW-Source: 2000-q1/msg00061.html

Kalle Olavi Niemitalo <tosi@ees2.oulu.fi> writes:

> Do you mean the default output port should be `emacs-port' in
> modules which use (emacs io), and stdout in others?  I don't know
> how that could be done.
> 
> In the current Guile Emacs, the (emacs io) module is loaded when
> it is first used, and at that moment the default ports change in
> all modules.  This is quite bad.  I see two ways around it:
> 
> a) Always load (emacs io), and do that as early as possible.
>    Then there won't be a sudden change later.
> 
> b) Do not change ports when loading (emacs io).  Anything that
>    wants to read or write through Emacs, must do something like:
> 
>      (use-modules (emacs io))
>      (with-output-to-port emacs-port
>        (lambda ()
>          (display "This goes to Emacs.")
> 	 (newline)))
> 
> Which alternative do you prefer?

I see.  a) is probably OK.

> > (I sometimes used display to the terminal for debugging...)
> 
> You could do that even if (emacs io) were always loaded:
> 
> (use-modules (emacs io))
> (with-output-to-port terminal-output-port
>   (lambda ()	
>     (let ((esc (string #\esc)))
>       (display (string-append esc "[32m"
>                               "This goes straight to the terminal."
> 	                      esc "[m")))))

Right.  And I guess I don't need that debugging any more.

> > We will turn this to the default some time later on.
> 
> I think it would be easier to do that now.

OK.  So, we have to think about the default behaviors now and
let the user notice that.  Could you document that?