TITLE: Vim fold expression for BibTeX files
DATE: 2019-07-31
AUTHOR: John L. Godlee
====================================================================


I wanted to be able to fold long BibTeX files to display a 
condensed list of the references so I could quickly scan the 
contents of the file. To do this, I created a function in my .vimrc 
which folds .bib files on the @ symbol which prepends each 
reference entry in the file. This is the excerpt from my .vimrc:

    " Set folding function for bibtex entries
    function! BibTeXFold()
        if getline(v:lnum) =~ '^@.*$'
            return ">1"
        endif
        return "="
    endfunction
    au BufEnter *.bib setlocal foldexpr=BibTeXFold()
    au BufEnter *.bib setlocal foldmethod=expr

The final two lines which start with au BufEnter set the method of 
folding to expression and identifies the expression to use 
(BibTeXFold()).