Re: [gentoo-dev] RFD: EAPI specification in ebuilds

[Rich Freeman <rich0@gentoo.org>]

On Sun, Mar 11, 2012 at 10:03 PM, Brian Harring <ferringb@gmail.com> wrote:
> Pragmatic reality, the eapi function actually would work fine.  As
> pointed out elsewhere, bash parses as it goes- which isn't going to
> change.

Unless the ebuild isn't written in bash...

How do you source the ebuild if you don't know what to use to source
it?  How do you know what to use to source it if you don't know the
EAPI?  Right now all the existing EAPIs use bash, but there is no
reason the file couldn't be xml, or python, or just about anything
else.

If we want to allow for that kind of flexibility, then it might make
sense to go ahead and state that our convention is to stick EAPI=5 in
one of the first few lines of the ebuild, or inside a comment, but
also go a step further and state that the text "EAPI=" cannot appear
elsewhere in the ebuild (or perhaps within the first 10 lines).  Just
about any file format we might use would allow us to make "EAPI="
appear in it, but not all could guarantee that it would occur at the
start of a line, or at the start of a line immediately after a #.

In any case, I can really see the KISS value in a very rigid syntax
that is trivial to parse.  Stuff like this almost makes me wish our
ebuilds already were xml files or such, with bash embedded inside
sections.  Finding a particular tag in an xml file is trivial as the
fundamentals haven't changed in 15 years.

Rich