cc: [EMAIL PROTECTED]
Subject: Re: [ast-developers] Expanding empty arrays
--------
> I just stumbled across a discrepancy when quoting empty variables.
>
> set -- ""; print $# # prints 1
> unset x; set -- "$x"; print $# # prints 1
>
> But:
>
> unset x; set -- "[EMAIL PROTECTED]"; print $# # prints 0
> typeset x; set -- "[EMAIL PROTECTED]"; print $# # prints 0
>
> I find this a little confusing. I always thought that any expression in
> double quotes which evaluates to nothing counts as one word.
>
The behavior is correct. The behavior of "$@" and "[EMAIL PROTECTED]"
expands to nothing if there are no arguments or array elements.
For "$@" this behavior is specified in POSIX and differs from the
Bourne shell. It makes things like
for i in "$@"
do...
done
behave as one would expect.
> Interestingly, bash exhibits a similar, though slightly more
> inconsistent behavior:
>
> unset a; set -- "[EMAIL PROTECTED]"; echo $# # prints 0
> typeset a; set -- "[EMAIL PROTECTED]"; echo $# # prints 1
>
> I asked for that on the bash list and got an answer from Chet Ramey:
>
> > ... Bash
> > has traditionally treated `typeset a' as equivalent to `typeset a=""'
> > instead of creating a `placeholder' variable that exists in a sort of
> > limbo. That's different from things like `export a' or `readonly a',
> > and probably inconsistent enough to be worth changing for bash-4.0.
>
> How is the situation in ksh? Is this behavior intended or will it also
> change some day?
If no attribues are specified, then typeset creates an unset variable.
So this is a difference.
>
> Regards,
> Bernd
>
> --
> Bernd Eggink
> [EMAIL PROTECTED]
> http://sudrala.de
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>
David Korn
[EMAIL PROTECTED]
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