#   This program is free software: you can redistribute it and/or modify
#   it under the terms of the GNU General Public License as published by
#   the Free Software Foundation, either version 3 of the License, or
#   (at your option) any later version.
#
#   This program is distributed in the hope that it will be useful,
#   but WITHOUT ANY WARRANTY; without even the implied warranty of
#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#   GNU General Public License for more details.
#
#   You should have received a copy of the GNU General Public License
#   along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
set -- "abc" "def ghi" "jkl"
A=("$@")

IFS=':'

echo 'IFS=: ${var-$*}'
unset var; printf '%s\n' ${var-$*}
printf '%s\n' ${var-${A[*]}}

echo "----"
echo 'IFS=: ${var=$*}'

unset  var; printf '%s\n' ${var=$*}
printf 'var=%s\n' "$var"

unset var; printf '%s\n' ${var=${A[*]}}
printf 'var=%s\n' "$var"

echo "----"
echo 'IFS=: ${var+$*}'

printf '%s\n' ${var+$*}
printf '%s\n' ${var+${A[*]}}

echo "----"
echo 'IFS= ${var-$*}'

IFS=''
unset var; printf '%s\n' ${var-$*}
unset var; printf '%s\n' ${var-${A[*]}}

echo "----"
echo 'IFS= ${var=$*}'

unset var
printf '%s\n' ${var=$*}
printf 'var=%s\n' "$var"

unset var
printf '%s\n' ${var=${A[*]}}
printf 'var=%s\n' "$var"

echo "----"
echo 'IFS= ${var+$*}'

printf '%s\n' ${var+$*}
printf '%s\n' ${var+${A[*]}}