Question

I frequently open whole sets of file at once from inside MacVim. To do this, I typically use the commands:

args *PATTERN*
argdo tabedit

This loads all files in the working directory that match the pattern into the argument list, and then opens them all in separate tabs. Syntax highlighting is not automatically turned on when I do this and I have to set it manually. How can I fix this?

Answer 1

I had already posted a workaround for :bufdo in a similar question; here is an extended version that handles your use case, too. Working around the automatic setting of 'eventignore' is quite tricky, therefore it’s amply commented:

" Enable syntax highlighting when buffers are displayed in a window through
" :argdo and :bufdo, which disable the Syntax autocmd event to speed up
" processing.
augroup EnableSyntaxHighlighting
    " Filetype processing does happen, so we can detect a buffer initially
    " loaded during :argdo / :bufdo through a set filetype, but missing
    " b:current_syntax. Also don't do this when the user explicitly turned off
    " syntax highlighting via :syntax off.
    " The following autocmd is triggered twice:
    " 1. During the :...do iteration, where it is inactive, because
    " 'eventignore' includes "Syntax". This speeds up the iteration itself.
    " 2. After the iteration, when the user re-enters a buffer / window that was
    " loaded during the iteration. Here is becomes active and enables syntax
    " highlighting. Since that is done buffer after buffer, the delay doesn't
    " matter so much.
    " Note: When the :...do command itself edits the window (e.g. :argdo
    " tabedit), the BufWinEnter event won't fire and enable the syntax when the
    " window is re-visited. We need to hook into WinEnter, too. Note that for
    " :argdo split, each window only gets syntax highlighting as it is entered.
    " Alternatively, we could directly activate the normally effectless :syntax
    " enable through :set eventignore-=Syntax, but that would also cause the
    " slowdown during the iteration Vim wants to avoid.
    " Note: Must allow nesting of autocmds so that the :syntax enable triggers
    " the ColorScheme event. Otherwise, some highlighting groups may not be
    " restored properly.
    autocmd! BufWinEnter,WinEnter * nested if exists('syntax_on') && ! exists('b:current_syntax') && ! empty(&l:filetype) && index(split(&eventignore, ','), 'Syntax') == -1 | syntax enable | endif

    " The above does not handle reloading via :bufdo edit!, because the
    " b:current_syntax variable is not cleared by that. During the :bufdo,
    " 'eventignore' contains "Syntax", so this can be used to detect this
    " situation when the file is re-read into the buffer. Due to the
    " 'eventignore', an immediate :syntax enable is ignored, but by clearing
    " b:current_syntax, the above handler will do this when the reloaded buffer
    " is displayed in a window again.
    autocmd! BufRead * if exists('syntax_on') && exists('b:current_syntax') && ! empty(&l:filetype) && index(split(&eventignore, ','), 'Syntax') != -1 | unlet! b:current_syntax | endif
augroup END