[gentoo-dev] EAPI-3 draft: slot operator support

[Mart Raudsepp]

Hello,


This thread is for any discussion about the slot operator support item
in EAPI-3 draft.

The premise is good what := and :* allow for, but I'm concerned about
the syntax possibly ending up being suboptimal in relation to the syntax
we come up in the future for covering the cases not covered now.


Such cases are for example:

* A library package has slots 2.4, 2.6 and 2.8. An application works
with either 2.6 or 2.8, but needs a recompile for changed ABI. It does
not work with 2.4 - it has API missing that it needs.
* Same case as previous, but additionally the library has a version with
slot 3.0 - it is a complete redesign and applications working with 2.8
have no chance of working. So need to express a list of acceptable SLOTs
or a minimum and maximum (but slots aren't really guaranteed to be
numeric and versionable).
* Same case as previous (either of them), but if using SLOT 2.6, it
needs to be at least >=libr/ary-2.6.5:2.6 and if SLOT 2.8 at least
>=libr/ary-2.8.3:2.8. A re-compile if switching provider may or may not
be necessary (considering both cases separately)

* A library provides slots 1.2, 1.4 and 1.6. An application can work
with all of them, but needs a recompile if upgrading from being linked
against 1.2 to newer. 1.4 and 1.6 are runtime interchangeable. Very rare
possibility of this though, involving dlopen and more. Probably
acceptable to declare rebuild need for all changes.


Are we sure := and :* is the syntax that makes sense once we try to
cover some of the above with new syntax?

Perhaps some forward thinking is sensible here to not end up with having
to deprecate the := and :* syntax soon after its introduction.



-- 
Mart Raudsepp
Gentoo Developer
Mail: leio@g.o
Weblog: http://planet.gentoo.org/developers/leio