Re: No word splitting for assignment-like expressions in compound assignment

[Alexey Izbyshev]

On 2020-07-27 10:06, Lawrence Velázquez wrote:
> > On Jul 27, 2020, at 1:31 AM, Dale R. Worley <worley@alum.mit.edu> 
> > wrote:
> > Interesting.  The documentation for 4.2.53(1) says this about 
> > parameter
> > assignments generally, with no special rules for compound assignments:
> >
> >       All
> >       values undergo tilde expansion, parameter and variable 
> > expansion,  com-
> >       mand  substitution, arithmetic expansion, and quote removal (see 
> > EXPAN-
> >       SION below).  ...  Word  splitting  is  not
> >       performed,  with the exception of "$@" as explained below under 
> > Special
> >       Parameters.  Pathname expansion is not  performed.
> >
> > So it seems like the word splitting in "A=(X$Z)" is incorrect.  So is
> > pathname expansion in that context.
>
>
> If word splitting were not performed in compound assignments, this...
>
>     foo=(a b c)
>
> ...would not work. If pathname expansion were not performed in compound
> assignments, this...
>
>     foo=(*)
>
> ...would not work. Arrays would become significantly less usable if
> word splitting and pathname expansion were not allowed in compound
> assignments.
To be clear, I don't consider word splitting and expansions in compound 
assignments to be a problem: this is well-known and long-standing 
behavior, even though it doesn't seem to be explicitly documented. In 
particular, I expect word splitting to happen in "A=(X$Z)" case. But I 
expect it to happen in "A=(X=$Z)" too, and the lack of it seems 
unintentional to me.

Alexey