To allow people to cherry-pick just a subset of them if other code
defines literals that may conflict. I first did that the same way as
STL (so both namespaces inline), only to subsequently discover the
horror that all literals are implicitly available in the enclosing
Math namespace, thus preventing no conflicts at all. So the Literals
namespace isn't getting inline, only the inner ones.
This is also in preparation for introduction of
Literals::ConstexprColorLiterals that would provide a constexpr variant
of the _srgbf literals at the expense of having a large LUT in a header
file.
I did this back in 2010 because it "felt like the right thing to do",
given that all of Magnum depended on Math and not vice versa. But,
strictly speaking, Math already uses typedefs from Magnum/Types.h so why
it couldn't also bring in the Corrade namespace, and the
Debug/Warning/Error names too. Having to type out Corrade:: in all these
was really just a waste of time, weird inconsistency in docs and an
extra roadblock for whoever might want to contribute anything there.
The old one is deprecated, and will be removed in a future release.
Unfortunately, to avoid deprecation warnings, all use of NoInit in the
Math library temporarily have to be Magnum::NoInit This will be cleaned
up when the deprecated alias is removed.