RE: PATCH: param stuff and was: PATCH: 3.1.5-pws-12: _brace_parameter

[Sven Wischnowsky <wischnow@informatik.hu-berlin.de>]

Andrej Borsenkow wrote:

> > It's actually completely predictable, once you know the rule.
> >
> 
> 'course. What I tried to explain, that there is probably a dozen of people,
> who know these rules :-( (correct me if I'm wrong)
> 
> O.K. Is it intentional?
> 
> itsrm2% foo=(axb cxd)
> itsrm2% print -l ${(s/x/)foo}
> a
> b c
> d
> 
> I won't argue, if this is correct or not. I'd just to point out
> a) if this is intentional, it should be documented
> b) it is very different from word splitting (which is referred to in
> manual). In this case, *every* resulting word is splitted:
> 
> itsrm2% foo=("a b" "c d")
> itsrm2% print -l ${=foo}
> a
> b
> c
> d

The `s' flag just says where to split -- without it is done at the
well known places, with it it is done only at the string given with
the flag.

> The second question is, what is applied first - flags or modifications?
> Again, after soms tests :-)
> 
> itsrm2% foo=(ax1 bx1)
> itsrm2% print -l ${(s/x/)foo%%1*}
> a
>  b
> 
> I don't argue, that it may be predictable. Unfortunately, I simply fail to
> find the rule ...

Modification is done first. Splitting is done at the very end, in this 
case.

So the above does: apply the `%%1*', yielding the two elements `ax'
and `bx'. The `s' flag makes them be joined as usual and then broken at 
the `x's, yielding the three elements `a', ` b', and `'. Since you
didn't enclose it in quotes that last one is removed so you can't see
it. But with `"${(@s/x/)foo%%1*}" you can. And I can almost see you
trying `print -l "${(s/x/)foo%%1*}" now ;-) Perhaps surprisingly this
gives `a' and `', because without the `(@)' flag, the array elements
are first joined and re-separated at the `x's and then the `%%1*' is
applied -- which looks a bit like a bug, but then again, maybe not.

Bye
 Sven


--
Sven Wischnowsky                         wischnow@informatik.hu-berlin.de