Re: [PATCH] Generic mechanism to detect shell features

[Eric Sunshine]

On Tue, 13 Jan 2004 00:12:56 +0100, Paolo Bonzini wrote:
> > Ideally we'd see a single proposal that does both.
> I'd agree with applying Eric's patch and working incrementally from there.
> What follows is a brief review:
> +AS_IF([test $as_fn_exitcode -eq 0],
> +  m4_ifval([$1], [$1], [:]),
> +  m4_ifval([$2], [$2], [:]))
> +])# _AS_SHELL_FN_WORKS
> The idea of AS_IF is to avoid those m4_ifvals, just do AS_IF([...], [$1],
> [$2]).

Indeed, this is an obvious simplification.

> Use _AS_SHELL_FN_SUPPORTED_FOR_SHELL([$SHELL]) in case the syntax is not
> supported, and drop _AS_SHELL_FN_SUPPORTED.

...{snipped a number of invalid comments based upon flawed assumption that  
SHELL is the currently running shell}...

> Otherwise looks great.

Your proposal for a generic detection mechanism is a good one.  If you can  
fix the fatal flaws which I discovered in your patch (such as assuming that  
SHELL is the running shell), then it would make more sense to just go ahead  
with generic mechanism rather than bothering with my patch.

-- ES