Parser question + Markdown "wysiwyg"

[Bodhi]

Hi all

I've started writing an OS X Markdown "editor"[1] that semi-formats your markdown document as you write it. I just wanted to put something together, so went with a regexp-based setup for parsing -- Not ideal! I'd really like to use an existing parser, but I need to get access to the parse-tree *with* character offets, rather than just html output, as I'm adding attributes to the string so it renders in a wyswig-esque manner, rather than actually transforming it.

I've looked briefly at discount and peg-markdown -- I'd prefer a C-based parser as the app is Objective-C -- but I'm not sure if it's possible to get a detailed parse-tree out of either of them? I thought I'd ask before digging around and hacking up either of them...

Bodhi

[1] http://keshiki.net/markdown-editor