Re: Expand array into multiple elements per item?

[Peter Stephenson <Peter.Stephenson@xxxxxxx>]

On Tue, 13 Sep 2011 04:15:50 -0400
"Benjamin R. Haskell" <zsh@xxxxxxxxxx> wrote:

> Three questions:
> 
> 1. How can I easily take:
> 
>      somelist=( 'a b' c 'd e' )
> 
> and get back:
> 
>      anotherlist=( -id 'a b' -id c -id 'd e' )

anotherlist=({-id,${^somelist}})

> 2. ...relatedly, I'm confused by the following:
> 
>       $ somelist=( 'a b' c 'd e' )
>       $ print -l - $somelist
>       a b
>       c
>       d e
> (i)  $ print -l - $^somelist(e:'reply=( -id $REPLY )':)
>       zsh: no matches found: a b(e:reply=( -id $REPLY ):)
> (ii) $ print -l - $^somelist(Ne:'reply=( -id $REPLY )':)
>       (...nothing printed...)
>       $
> 
> Why does neither (i) nor (ii) work?

The main problem is that globbing flags rely on globbing; if there's no
matching file, it doesn't work.  You'd probably want "oN" in the
globbing flags to turn off sorting if you did have files.

> 3. I thought I recalled a relatively recent addition to parameter 
> expansion flags for just this use-case.  But I can't seem to find the 
> flag in zsh-4.3.12 patchlevel 1.5346.  Still interested in the answer to 
> the rest, regardless.

You might be thinking of the globbing flag, P.  If you did have files,
*(P:-id:) would have done what you wanted.  But you don't.  The actual
effect is a bit bizarre (turning off nomatch):

-id
a b(P:-id:)
-id
c(P:-id:)
-id
d e(P:-id:)

-- 
Peter Stephenson <pws@xxxxxxx>            Software Engineer
Tel: +44 (0)1223 692070                   Cambridge Silicon Radio Limited
Churchill House, Cambridge Business Park, Cowley Road, Cambridge, CB4 0WZ, UK


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