How to write a Gentoo ebuild file , with LINGUAS support

I wanted to write a ebuild for some binary package , it contains a folder for different languages , its structure is:

ls /path/po:

de  fr  ja  zh_CN  zh_TW

I think it's easy to do it , but the document provided by Gentoo is really limited , how can i filter the unnecessary language files ? I shouldn't be copying all those to /usr/share/locale.

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@Updates:

I discovered a simple method , which examines ${LANGUAS} variable , like the following code:

insinto /usr/share/locale
for x in "${LANGUAS}";do
  if [[ 开发者_如何学C-d "po/${x}" ]];then
    doins "po/${x}"
  else
    einfo "LANGUAGE $x is not supported by this app"
  fi
done

Just wondering if it's official approach.

There isn't an official approach as it is very package dependent. For example, some packages may require additional parameters to be passed to ./configure while others, like your, require a more manual approach.

As for your example above, I believe it to be perfectly acceptable. You haven't provided the whole ebuild so just remember that you need to be adding the acceptable languages into the IUSE var.

e.g.

LANGS="de fr ja zh_CN zh_TW"
for X in ${LANGS} ; do
    IUSE="${IUSE} linguas_${X}"
done

For a more complicated example you could check out the openoffice-bin ebuild