Re: 'emulate sh -c' and $0

[Richard Hansen <rhansen@bbn.com>]

On 2014-05-31 01:13, Bart Schaefer wrote:
> If we leave FUNCTION_ARGZERO as it is (that is, off by default for sh
> emulation) and add an option POSIX_ARGZERO which exposes the global
> argzero when set (inverting your Option #2) but which is never on by
> default, then bin_emulate can set POSIX_ARGZERO in the -c scope when
> emulating sh/ksh, and it will be sticky for functions defined there.
> 
> We wouldn't even have to build those smarts into bin_emulate; a user
> who wanted the POSIX semantics could explicitly do
> 
>     emulate sh -o POSIX_ARGZERO -c '...'
> 
> The only "magic" necessary is that POSIX_ARGZERO exposes the original
> value of $0 in spite of the current FUNCTION_ARGZERO setting.
> 
> Here are the bits outside bin_emulate, and not yet with doc.  I suppose
> there may be some places where posixzero needs to be saved / changed /
> restored, which this hasn't covered.

Wow, thank you for committing this change to master!  It works well in
my limited testing, except for the documented limitation that
POSIX_ARGZERO stays enabled when calling a non-emulated function from a
function defined in 'emulate <shell> -c'.  I'm not sure how much this
will matter in practice, but if backward compatibility wasn't a concern
it'd be nice if zsh temporarily restored options when invoking a
function outside the 'emulate <shell> -c' boundary.

Although it would be a behavior change, I think it would be best if both
'emulate sh' and 'emulate sh -c' set POSIX_ARGZERO by default:  I
suspect that someone who runs 'emulate sh' cares more about accurate sh
emulation than compatibility with previous sh emulation behavior.  :)

Thanks,
Richard