I'm looking for a OS X markdown (or similar) editor that has an edit and a view mode. I want to view the rendered document by default and have an edit mode to change the content. Just in the way most wikis work.
Day One uses edit/view modes but it doesn't let me edit arbitrary text files.
On iOS I found Trunk Notes.
I am not looking for an editor with a preview. I want to see either Markdown or rendering.