Introduce static indices _0, _1, _2 as shortcuts for std::integral_constant<std::size_t,0> etc.

These indices have existed in dune-typetree for a while. They are already used extensively in dune-typetree and dune-functions, and they also make working with MultiTypeBlockVector/Matrix from dune-istl much nicer. They work very much like std::placeholders:_1, std::placeholders::_2, etc. We would have like to use that, but there is no std::placeholders_0.

This patch also introduces

template<std::size_t i>
using index_constant = std::integral_constant<std::size_t, i>;

which helps decrease code verbosity a little bit.

Added 13 commits:

• b8e93a09...0d2a9d42 - 9 commits from branch master
• 2d56637e - Rename indicestest.cc to remoteindicestest.cc
• 6cae75f0 - Introduce static indices _0, _1, _2 as shortcuts for std::integral_constantstd::size_t,0 etc.
• db0497d5 - Add unit test for the new static indices
• 9d376cb6 - Remove accidentally added include from typetree

I removed a wrong include and rebased the branch. Works for me now.

Added 1 commit:

• 9159760f - [cleanup] Strip down includes to the minimum

No further comments -- we are merging!

Status changed to merged

mentioned in commit 88cfef67

Mentioned in commit 88cfef67