Re: is the virtual package <locale>-tanslation correct?

[Phil Blundell <philb@gnu.org>]

On Tue, 2012-04-24 at 17:33 +0100, Richard Purdie wrote:
> On Tue, 2012-04-24 at 11:48 +0100, Phil Blundell wrote:
> > On Tue, 2012-04-24 at 11:45 +0100, Richard Purdie wrote:
> > > On Tue, 2012-04-24 at 10:42 +0100, Phil Blundell wrote:
> > > > Yes, that is the intended behaviour.  This is necessary to support
> > > > dynamically installed language packs.
> > > 
> > > What uses this out of interest?
> > 
> > I'm not entirely sure to be honest.  We used to use it quite heavily in
> > Familiar but I have no idea whether Angstrom does the same.  The systems
> > I'm working on nowadays don't tend to require language packs so I
> > haven't personally used that mechanism for a while.
> 
> How did the system use this? I can imagine querying the list of
> installed packages and then attempting installing xx-locale as a resuilt
> but I'm not sure how this other provider helps?
> 
> As far as I know, opkg doesn't directly support anything like this?

Ipkg did have (and I assume opkg still has, though I haven't checked) a
"greedy depends" mechanism which works exactly like this.  If it sees a
line like:

Recommends: xx-locale*

then it will install all the packages which Provide: xx-locale and whose
dependencies are already satisfied.  The way we used this in Familiar
was that the .ipk containing message catalogs for language CC and
package PN would Provide: PN-locale, CC-translation, and would Depend:
on PN and locale-base-CC.  PN itself would Recommend: PN-locale*, and
there was a language-pack-CC metapackage which would Depend: on
locale-base-cc and Recommend: CC-translation*.  So...

- if you did "ipkg install language-pack-de", it would install
locale-base-de (via the hard Depends) and then install PN-locale-de for
each PN that was already installed (via the Recommends).

- if you did "ipkg install frozen-bubble", it would install the program
itself (obviously) and then install the message catalogs for all the
locale-bases that were already installed.

Likewise, if you subsequently removed locale-base-de or frozen-bubble
then the dependency chain would cause all the corresponding message
catalogs to get ripped out as well.

Obviously this was about a decade ago so my recollection might not be
100% reliable.  But I'm fairly sure that the basic gist of the above is
correct.

p.