Re: Changed behaviour of 'split-at' with guilev2

[Thomas Morley]

Am So., 14. Okt. 2018 um 11:56 Uhr schrieb David Kastrup <address@hidden>:
>
> Thomas Morley <address@hidden> writes:
>
> > Hi,
> >
> > I stumbled across different behaviour of 'split-at' in guilev1/2. Doing
> > (define (foo) (write (split-at '(1 2 3) 1)))
> > (foo)
> > returns
> > in guilev1
> > #<values ((1) (2 3))>
> > in guilev2 only
> > (1)
>
> I rather think that Guilev2 just deals a bit differently with multiple
> values, dropping additional values in scheme-only contexts with
> single-value takers like `write'.

It bombed out one of my codings, before I found the culprit.

>
> > (define (buzz-II)
> >   (let-values (((x y) (split-at '(1 2 3) 1)))
> >     (list x y)))
> >
> > Actually we use split-at two times in our source
> > (1) In 'split-at-predicate' from lily-library.scm
> > There the method using call-with-values is already in work.
> > (2) In 'insert-lyrics*!' from song.scm
> > This should probably be fixed as well. Or is it already?
>
> It uses receive, which uses call-with-values.

Good to know.

> > I don't understand what's it's all about there. Ok, we have some
> > regtests about this (and the derived 'festival'), so I my educated
> > guess would be: it has to do with xml...
> > But there is _no_ documentation at all, as far as I can tell.
> > I'm at a loss with this :(
>
> I vaguely seem to remember that it was stuff in/for the toolbox of a
> user with impaired sight, but I haven't really the foggiest in what
> respect.  Maybe it was for having a speech synthesizer sing lyrics from
> a score?  I'd imagine this to be of slightly appalling appeal.

Well, can't judge about it without diving deep into it, for which I
currently neither have the time nor the energy or motivation.
Needless to say, without any docs probably nobody will ever notice or
even improve this coding unless it breaks.

Thanks,
  Harm