Update .po and strip down untranslated entries.

[omasanori]

This work is done by execute these commands manually:

$ po4a --copyright-holders="The Rust Project Developers" \
    --package-name="Rust" \
    --package-version="0.10-pre" \
    -M UTF-8 -L UTF-8 \
    doc/po4a.conf
$ for f in doc/po/**/*.po; do
>   msgattrib --untranslated $f -o $f.strip
>   if [ -e $f.strip ]; then
>       mv $f.strip $f
>   else
>       rm $f
>   fi
> done

It should be managed by the build system automatically to use in our
translation workflow, but I've not yet done that.

At least one mostly-translated (over 80% translation rate) document is needed to test the translation workflow, so I'll working on Japanese translation.

[alexcrichton]

This looks nice! Is this procedure documented anywhere in the translation files? I just want to make sure that this isn't the only location that this is written down.

[omasanori]

@alexcrichton Not yet.

The instruction is also in the commit log, but certainly it's better to write current hacky way to anywhere until a better way is available. Please wait.

[alexcrichton]

Do you plan on making a nicer way soon? If so I'll go ahead and r+ this, but if making it work in the near future won't happen then I'm hesitant to merge.

[omasanori]

I can't promise because the current Makefile doesn't work well for translation and testing it requires mostly translated documents. The best translation rate is 33.92% (tutorial.md) now. I have to increase this to 80+% first.

I can wrap these long commands in a few of shell scripts to make it easy now. Is it enough for a while?

[alexcrichton]

Can you add these in a comment to doc/po4a.conf?

[omasanori]

Well, what is "these"?

[brson]

@omasanori Thank you for continuing to improve our translation, and sorry we're not giving you more help (I still don't know anything about translation). If you think we need changes to the build system to improve our translation workflow that's probably something we can help with pretty easily. Keep filing issues and submitting PRs!

[omasanori]

@brson You're welcome.

At least in Japan, there are people that want a translation of official docs. I appreciate all efforts to keep up-to-date and improve the docs.

The problem is, po4a takes multiple file paths via po4a.conf and puts multiple outputs to the paths that are declared in po4a.conf, so it is difficult to track dependencies from make. I think the localization part of mk/docs.mk needs more considerations. For now, make docs-l10n does nothing even if some files related to translation have been updated.

[omasanori]

I've rebased to keep up with latest changes, fixed some critical typos and added more notes. I didn't grasp what @alexcrichton means "these in a comment", so I think it is not ready for merge.

[alexcrichton]

Sorry for being a little unclear, but I was just referring to the documentation that you added to README.md, that's great, thanks!