After considering all these options for some time, I have settled with the following solution.
- Set vim to write continuously as I type.
- Run a script in the background to build continuously, refreshing the pdf as it goes. latexmk is nearly good enough, except that it builds in place, which gets reloaded at a bad time in okular (my viewer).
The script is available at https://github.com/pbiggar/texbuild.
Use rubber-info to get the errors and warnings from the log file. The script above saves the log file in t.log. In vim:
autocmd FileType tex set makeprg=rubber-info\ t.log
autocmd FileType tex set errorformat=%f:%l:\ %m
