On 11.02.2014 20:54, Nicola Gigante wrote:
I’m recently starting to follow the Eigen project and I was
wondering which is the current status
of C++11 features support inside the library. It seems the library
is “compatible” with C++11,
meaning that it compiles and works properly with the new standard,
but does not take
advantage of new features when available.
Generally, we want to keep Eigen C++03 compatible as much as
possible. There are C++11 things implemented which don't jeopardize
that, like move semantics.
https://bitbucket.org/eigen/eigen/src/90f8b868e6e2/Eigen/src/Core/Matrix.h?at=default#cl-220
Things like initializer lists might encourage people to rely on that
and causing trouble when back-porting to C++03. We might allow things
like that if the user explicitly includes something like
<Eigen/CXX11/Core> -- we already had a similar discussion about that
for the tensor module:
http://listengine.tuxfamily.org/lists.tuxfamily.org/eigen/2013/11/msg00000.html
** Addendum after reading the link from Jitse's mail: It appears
initializer lists have much less power than our current
CommaInitializer
I think most other features you suggested are at the moment a bit
risky having still a lot of compilers around without or with
incomplete C++11 support.
IMHO we could consider using features if they give (measurable)
performance improvements, but for now I wouldn't do it "just" for
cleaner code or minor compile time reductions. We'd have to guard it
with #ifdefs anyhow to keep C++03 compatibility, essentially making
the code less clean.
I hope I did not entirely block you from contributing to Eigen. In
the long run we definitely want more C++11 features in Eigen, but for
now we should not risk C++03 compatibility.