Re: [gentoo-devhelp] sci-libs/sympy USE flags

[Peter Volkov]

Generally I tend to name use flags based on features they enable instead
of dependencies they require as this better documents what feature this
use flag enables. But soon (I hope) we'll have better ways to document
USE flags so things could change in near future.


В Срд, 23/01/2008 в 10:37 +0100, Thomas Pani пишет:
> - sympy uses libxml2 and libxslt to generate MathML code. Which USE-flag
> would be more appropriate, `xslt' or `math' (or intruduce `mathml')?
> app-office/abiword-plugins and www-apps/mediawiki both use the math use
> flag to enable math rendering, but as Andrey Grozin pointed out sympy
> provides math rendering via LaTeX, mathml, TeXmacs, so using `math'
> would be ambiguous.

mathml is good choice.

> - Should there be a USE-flag that pulls in TeXmacs? If yes, which one?

If package allows to disable/enable this feature then yes. Call it USE
flag texmacs or latex as you chose.

> - Once again for plotting. Uses pyglet ([2]), which is not yet in
> portage but comes packaged with sympy. Which USE flag? Just `opengl' or
> a new  `plot' flag?

Does potting works without pyglet? Does package works without pyglet? If
this just adds opengl support for plotting then opengl is good choice of
USE flag too.


Generally I think ebuild uses USE flags only for dependencies but it
should also use them to configure package. See:

http://devmanual.gentoo.org/ebuild-writing/functions/src_compile/configuring/index.html

"Often the configure script will try to automatically enable support for
optional components based upon installed packages. This *must not* be
allowed to happen."

So in your case you need to tweak build system somehow to allow package
be built without plot support even if dev-python/pyopengl,
dev-python/imaging and dev-python/ctypes are installed.

-- 
Peter.