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()).