${var:+foo "$empty"}

[Stephane Chazelas]

Hi,

$ bash -c 'printf "<%s>\n" ${$:+a "$a"}'
<a>
$ ksh -c 'printf "<%s>\n" ${$:+a "$a"}'
<a>
<>
$ dash -c 'printf "<%s>\n" ${$:+a "$a"}'
<a>
<>
$ bash --version
GNU bash, version 3.00.16(1)-release (i386-pc-linux-gnu)
Copyright (C) 2004 Free Software Foundation, Inc.

Same, when replacing ":+" with -, +, :-.

It's OK when I replace "$a" with "$@", though:

$ bash -c 'printf "<%s>\n" ${$+a "$@"}' - ''
<a>
<>

regards,
Stéphane