function translate_var_refs(str, _out, _name) {
    _out = ""
    while (match(str, /%\[[a-zA-Z0-9_]+\]/)) {
        _out  = _out substr(str, 1, RSTART-1)
        _name = substr(str, RSTART+2, RLENGTH-3)
        _out  = _out sprintf("${DATA_%s-%[%s]}", _name, _name)
        str   = substr(str, RSTART + RLENGTH)
    }
    _out = _out str
    return _out
}

function escape_shell(str) {
    gsub(/\\/, "\\\\", str)
    gsub(/'/, "\\'", str)
    gsub(/"/, "\\\"", str)
    gsub(/\$/, "\\$", str)
    return str
}

BEGIN {
    begin=0
}

{
    if (!begin) {
        printf "export FILENAME='%s'\n", FILENAME
        printf ". preproc/lib.sh\n"
        begin=1
    }
}

/^%~/ {
    print substr($0, 3)
}

/^%[a-zA-Z0-9_]+:/ {
    _split = index($0, ":")
    _name  = substr($0, 2, _split-2)
    _value = substr($0, _split+1)
    printf "export DATA_%s='%s'\n", _name, escape_shell(_value)
}

!/^%%|^%~|^%[a-zA-Z0-9_]+:/ {
    printf "printf '%%s\\n' \"%s\"\n", translate_var_refs(escape_shell($0))
}