Re: [Chicken-users] read-line

[Joerg F. Wittenberger]

Felix Winkelmann <address@hidden> writes:

> Joerg F. Wittenberger wrote:
> > Hi,
> > I found read-line working somewhat unexpected on network streams
> 
> > (where the ^M^J or the "apple" line feed rule applies): it inserts
> > empty lines in between the line feed.
> > Anybody who objects this change, which understands any of:
> 
> >  #\newline #\return  #\return #\newline
> 
> >  #\newline
> >  #\return as line delimiter.  Sequences, though, should result in
> > empty lines.
> 
> There is one little problem, though: when reading data
> interactively, and we have normal (1-byte) line-terminators,
> then your solution will have to read the next line from the user,
> before it can process the current line.

true.  hm.  that trap is just ahead.

> I propose to add an optional flag to `read-line' that
> states wether extra line-terminators should be consumed
> or not (defaulting to not).

I would propose a different route:

a) by default read up to #\newline, if the preceeding char in
#\return, don't include it in the result string.

b) a flag to switch the roles of #\newline and #\return from the
default behavior.

This should cover the "apple case" as exception and work just fine for
unix and network convention.

/Jörg

-- 
The worst of harm may often result from the best of intentions.