For a while, I've been envious of some of the project and file navigation features in emacs for browsing bigger projects/programs, things like imenu and tags have always seems awesome but given that I spend most of time editing restructured text and markdown files (I'm a technical writer), these tools have been distant and not a part of my day to day work.

It's not that it would be impossible to write interfaces for imenu or etags, for the formats I use regularly, but more that I've never gotten around to it until now.

We're still a ways away on the question of etags, but it turns out that when I wasn't looking rst mode got imenu support, and with the following little bit of elisp you can get imenu for markdown.

(setq markdown-imenu-generic-expression
   '(("title"  "^\\(.*\\)[\n]=+$" 1)
     ("h2-"    "^\\(.*\\)[\n]-+$" 1)
     ("h1"   "^# \\(.*\\)$" 1)
     ("h2"   "^## \\(.*\\)$" 1)
     ("h3"   "^### \\(.*\\)$" 1)
     ("h4"   "^#### \\(.*\\)$" 1)
     ("h5"   "^##### \\(.*\\)$" 1)
     ("h6"   "^###### \\(.*\\)$" 1)
     ("fn"   "^\\[\\^\\(.*\\)\\]" 1)
))

(add-hook 'markdown-mode-hook
   (lambda ()
      (setq imenu-generic-expression markdown-imenu-generic-expression)))

Pretty awesome! I hope it helps you make awesome things.