bash localization won't work with multilines strings (with strong syntax or through `eval`)

I've played a little bit with this feature and this is what I came up with: you can include the newline verbatim as:

$ echo $"Written by %s.
> "
Écrit par %s.
$ 

In a script:

#!/bin/bash

message=$"Written by %s.
"

printf "$message" Gniourf

This script will output:

Écrit par Gniourf.

Ok, this is not really an answer, but it might help a little bit (at least, we're not using the evil eval).

Personal remark: I find this feature really clunky!

If using eval is bad with arbitrary variables, there is a way to do this only when called/needed, in running eval only on message part:

function lPrintf() {
    local sFormat="$(
        eval 'echo $"'"${1}"'"'.
    )"
    shift
    printf "${sFormat%.}" $@
}

lPrintf "system boot"
démarrage système

lPrintf  $'Written by %s, %s, %s,\nand %s.\n' techno moi lui-même bibi
Écrit par techno, moi, lui-même,
et bibi.

( The dot at end of translated string ensure that whole string, including leading line-break, where passed to variable sFormat. They will be dropped with ${sFormat%.} )

OK I think finally got it right.

iprintf() {
    msg="$2"
    domain="$1"
    shift
    shift
    imsg=$(gettext -ed "$domain" "$msg" ; echo EOF)
    imsg="${imsg%EOF}"
    printf "$imsg" "$@"
}

Usage example:

LANG=fr_CH.utf8 iprintf coreutils "If FILE is not specified, use %s.  %s as FILE is common.\n\n" foo bar