Vim Markdown Folding?

Question

I just realized that VIM 7.3 has built-in support for highlighting Markdown files. Excellent. However, it doesn\'t fold on the headings.

Can any offer suggestions on

Answer 1

Based on Jeromy & Omar's suggestions, I came up with this (for my vimrc) to automatically and unambiguously fold my DokuWiki files (in which top level header is marked by ====== at start of line, down to fourth level header marked by ===):

function! DWTitleLevel()
    let j = len(matchstr(getline(v:lnum), '^=\+'))
    if     j =~ 6 | return ">1"
    elseif j =~ 5 | return ">2"
    elseif j =~ 4 | return ">3"
    elseif j =~ 3 | return ">4"
    endif
endfunction

'^=+' means match from the start of the line any number of contiguous '='s

Then this in a vim modeline makes it work nicely for a DokuWiki file:

foldmethod=expr foldexpr=DWTitleLevel() foldcolumn=5

And for Markdown, I needed to write Omar's code like this:

if empty(j) | return "=" | else | return ">".len(j) | endif