I just finised a short stint working on UE4. One of my problems was Emacs. It just isn't scaling for the kind and size of projects that I have to tackle. UE4 is much more decomposed than UE3 and there are dozens and dozens of directories to tag. While Exuberant Ctags is an excellent technology for tagging source, it's slow to run over many, many directories.I need an intelligent daemon that can watch directories for change and re-run ctags as needed.
The second problemis that analysing source isn't the only route to finding semantic information these days: both the JVM and .NET support reflection - and this is the preferred route to find things like type names, function signatures, etc. Some code has to be written that can reflect on assemblies and class files and be fed into a tags database or auto-completion solution so that the class libraries can be discovered interactively.
I'm hoping there are open source projects there that would get me at least halfway to this functionality.
The third problem, which I'm likely to tackle myself is flymake. Flymake is predicated around the assumption that full builds are too expensive to do, and selective builds of a single file, in order to check it are the way to go. This does not fit with many build tools which manage large amounts of dependencies on a big project and build only the one changed file in any case. When flymake originated this was far too an expensive an operation to be performed interactively, but in a world of multi-gigabyte memory, and sixty-four-bit multicore this is no longer true. So I'm going to change that aspect of it.
Any more suggestions welcome.