This is a relatively drastic change that should have been done
progressively, but I got carried away in ripping everything out and
putting it back in again.
Reading the documentation for writing a Vim script (:help usr_41.txt), I
am convinced that all of the content that was in the vim/ftplugin
directory and some of the vim/indent directory actually belonged in
vim/after/ftplugin and vim/after/indent respectively.
This is because the section on filetypes makes the distinction between
replacing the core filetype or indent plugins and merely adding to or
editing them after the fact; from :help ftplugin:
> If you do want to use the default plugin, but overrule one of the
> settings, you can write the different setting in a script:
> setlocal textwidth=70
> Now write this in the "after" directory, so that it gets sourced after
> the distributed "vim.vim" ftplugin after-directory. For Unix this
> would be "~/.vim/after/ftplugin/vim.vim". Note that the default
> plugin will have set "b:did_ftplugin", but it is ignored here.
Therefore, I have deleted the user_indent.vim and user_ftplugin.vim
plugins and their documentation that I wrote, and their ftplugin.vim and
indent.vim shims in ~/.vim, in an attempt to make these plugins
elegantly undo-ready, and instead embraced the way the documentation and
$VIMRUNTIME structure seems to suggest.
I broke the ftplugin files up by function and put them under
subdirectories of vim/after named by filetype, as the 'runtimepath'
layout permits. In doing so, I also carefully applied the
* Short-circuiting repeated loads
* Checking for existing mappings using the <Plug> prefix approach
* Avoiding repeated function declarations overwriting each other
* Guarding against 'cpotions' mangling things (by simply
short-circuiting if 'compatible' is set).
I've made the b:undo_ftplugin and b:undo_indent commands less forgiving,
and append commands to it inline with the initial establishment of the
setup they're reversing, including checking that the b:undo_* variable
actually exists in the first place.
For the indentation scripts, however, three of the four files originally
in vim/indent actually do belong there:
1. csv.vim, because it doesn't have an indent file in the core.
2. tsv.vim, because it doesn't have an indent file in the core.
3. php.vim, because it does what ftplugins are allowed to do in
preventing the core indent rules from running at all.
The indent/vim.vim rules, however, have been moved to
after/indent/vim.vim, because the tweaks it makes for two-space
indentation are designed to supplement the core indent rules, not
Finally, I've adjusted Makefile targets accordingly for the above, given
the vim/ftplugin directory is now empty and there are three new
directories in vim/after to install. We wrap these under a single
`install-vim-after` parent target for convenience. The
`install-vim-after-ftplugin` target accommodates the additional level of
filetype directories beneath it.