Menu-spec update (Was: [Patch] Update 'How to' to clarify computation of datadir)

[Jeremy White]

>   ./install-some-software.sh --prefix=/mnt/shared
> 
> (or PREFIX=/mnt/shared ./install-some-software.sh, if you prefer).

Um, you've just added  '--prefix' to the mix; that does
not exist in any specification.  You're saying that all application
installers must respect an environment variable of PREFIX
or a flag of --prefix?

And I'm fully aware that there are other ways that a system
admin could get this basic job done; many of them are a PITA,
but doable.

My point was more to illustrate the value of flexibility and
(by implication) the evil of hard coding.

> 
> XDG_DATA_DIRS is a directive for reading (and coalescing) multiple
> source locations. But that should not be mixed with install-prefix
> directives, which always should unambiguously name a single directory.
> So whatever mechanism an installer uses to identify the prefix to
> install to, it should *not* be XDG_DATA_DIRS.

That strikes me as a legitimate point.

In fact, reading this page:
  http://standards.freedesktop.org/basedir-spec/latest/ar01s02.html

makes it glaringly obvious to me that there is a clear specification
as to where user specific changes are to be written, and a clear
spec as to where things should be read from.  But there is no clear
spec as to where system level things should be written.

I'm not opposed to the addition of a XDG_WRITE_DATA_DIRS specification
addition to the basedir-spec.  In fact, I would assert that Waldo
is essentially saying that XDG_WRITE_DATA_DIRS exists and is
always hard coded to /usr/share:/usr/local/share.

I still feel that having XDG_DATA_DIRS be both read and write can
be a reasonable spec, but I can see rational arguments against.

Cheers,

Jeremy