pkg question - Difference pkg vs port

[Gary Palmer]

On Wed, Sep 03, 2014 at 07:32:48PM -0400, Brandon Allbery wrote:
> On Wed, Sep 3, 2014 at 7:24 PM, Michael Ross <gmx at ross.cx> wrote:
> 
> > "Anything that provides" I think is the key to where I started thinking
> > wrong:
> >
> > The dependency is not "Shared libs required" libmysqlclient.so.18,
> > but one specific port that provides libmysqlclient.so.18 - mysql55-client.
> >
> 
> Ports can do "provides library" dependencies. Packages can only depend on
> packages. You can try to force it but you could also confuse your package
> database rather badly.

Why can't packages check to see if the library exists and use it if it
does?  RPM does something like that, although I think they go much
further with that process.

In this case, AFAIK the mysql client library API is stable - the 5.5 and
5.6 library versions should have the same API so the requirement to
install the 5.5 package is a bit silly.

(I'm dreading this e-mail taking us down the RPM path of dozens of
 different packages that make up one program, foo-devel, foo-libs,
 foo-client, etc)

Gary