check if variable is array, returns 0 on success, 1 otherwise

is_array.sh

## Check if variable is array
 # @param mixed
 # @return integer   0 on success, 1 otherwise
 #
 # @example
 #  value=("i'm an array" "and that's my 2nd value")
 #  if is_array value; then
 #      echo 'value is an Array'
 #  else
 #      echo 'value is NOT an Array'
 #  fi
is_array () {
    # 1st arg is a null string => false (1)
    [ -z "$1" ] && return 1

    # bash is the runtime; $BASH string is not null
    if [ -n "$BASH" ]; then
        # check for array declaration on 1st arg; disable error output => true (0)
        declare -p ${1} 2> /dev/null | grep 'declare \-a' >/dev/null && return 0
    fi

    # no result => false (1)
    return 1
}