Re: FYI: fix m4_cdr

[Ralf Wildenhues]

* Ralf Wildenhues wrote on Wed, Jun 08, 2005 at 10:07:31AM CEST:
> * Stepan Kasal wrote on Mon, Jun 06, 2005 at 10:45:23AM CEST:
> >   I fixed m4_cdr.  It returned [[]] where it should have returned an
> > empty list.  m4_foreach, which also confused these two, was fixed, too.
> > 
> > These changes could break code which depended on this misbehaviour;
> > but I don't expect to see this in practice.
> 
> This patch breaks bootstrapping of Libtool (at least; tested with CVS HEAD)
> when GNU m4 1.4.1 is used:

Could this interface (m4_car/m4_cdr) be published?
For now, Libtool employs a copy of it so it can cope with both 2.59 and
CVS HEAD.  But I'd like to remove that eventually again (after 2.60 is
out) and be sure not to fall on the ground again.  :)

Cheers,
Ralf

> > 2005-06-06  Stepan Kasal  <address@hidden>
> > 
> >     m4_cdr of one-member list was [[]] (one-member list containing an
> >     empty string) instead of [] (an empty list.  Callers were skewed to
> >     match this misbehaviour.  As a consequence of this:
> >      - m4_foreach([x], [], [foo]) expanded to `foo', while
> >      - the expansion of m4_foreach([x], [[]], [foo]) was empty.
> >     I fixed this bug.
> > 
> >     * lib/m4sugar/m4sugar.m4 (m4_cdr): If only one argument is given,
> >       expand to an empty string; print error msg if called without
> >       an argument list.
> >     (m4_foreach, m4_map, m4_map_sep): Don't expect the previous
> >       misbehaviour; handle [] and [[]] correctly.