Re: (b)make: selecting every other element from a list

[Joerg Sonnenberger <joerg%britannica.bec.de@localhost>]

On Thu, Sep 03, 2015 at 10:30:00PM +0100, David Laight wrote:
> On Thu, Sep 03, 2015 at 06:37:32PM +0200, Edgar Fu? wrote:
> > Thanks.
> > 
> > > l2:=
> > Any particular reason for using := and not = in this place?
> > 
> > > .for _i _j in $(l)
> > > l2+=$(_i)
> > > .endfor
> >
> > Oops. I was sure this didn't work in older (NetBSD 4.0.1) versions of (b)make, 
> > but I just checked it does work. I (wrongly) remembered this ending up in l2 
> > being ${_i} ${_i} ${_i} after the loop, and subsequent expansion of ${l2} 
> > repeating the last value ${_i}?was set to. Strange.
> 
> It used to be difficult to get the required delayed expansion of the loop
> variables.
> I fixed it a while ago by some magic transformation I can't quite remember.

You changed it into :U${current_value}.

Joerg