Re: pkg/51142: pdksh has occasional issues with empty 'for' loops

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

On Mon, May 16, 2016 at 04:55:01AM +0000, Richard PALO wrote:
> The following reply was made to PR pkg/51142; it has been noted by GNATS.
> 
> From: Richard PALO <richard%netbsd.org@localhost>
> To: gnats-bugs%NetBSD.org@localhost
> Cc: 
> Subject: Re: pkg/51142: pdksh has occasional issues with empty 'for' loops
> Date: Mon, 16 May 2016 06:52:36 +0200
> 
>  Le 15/05/16 19:30, Joerg Sonnenberger a écrit :
>  >  That's not a shell bug, but a "feature" of the standard. A common
>  >  pattern found e.g. in mk/ is to explicit append '' (empty string) and
>  >  short cut with [ -n "$i" ] || break
>  >  
>  >  Joerg
>  
>  Indeed! 
>  http://pubs.opengroup.org/onlinepubs/009604499/utilities/xcu_chap02.html#tag_02_14
>  does say:
>  > The format for the for loop is as follows:
>  > 
>  >     for name [ in [word ... ]]do
>  >         compound-list
>  > 
>  > 
>  >     done

Actually, you are looking at a too-new version. Try SUSv2 for example:
http://pubs.opengroup.org/onlinepubs/7908799/xcu/chap2.html#tag_001_009_004_002

    for name [ in word ... ]
    do
        compound-list
    done

...and that has been interpreted historically by some shells (this one
included) to mean that after the "in" something must be found. The BNF
grammar is similar problematic. I'm not really objecting to fixing this
is pdksh, but be careful to call it a bug.

Joerg