Still, MMD is a nice option at times, and has at least one significant advantage over LaTeX: it is lightweight both in its processing and in its writing, so it is easy to do on any computer. On my Macs, I'm using SubEthaEdit (SEE) to compose and have just purchased Marked to preview. Marked is quite a nice design, intended to work with any editor (in proper Unix philosophy!) and automatically updating the preview whenever the document is saved (pleasantly reminiscent of Latexmk, albeit with a much easier task). Marked is also inexpensive (three bucks!) through the Mac App Store. Unfortunately, Marked 1.1 seems to be a little buggy, but its author has said that he's already fixed the bugs I reported, with the updated version waiting to finish the review process.
While already a pretty elegant combination, I present below a script to streamline the combination of SEE and Marked a little more. You'll need to install the Markdown mode for SEE. Show the package contents and save the script below into the Scripts folder within. While you're there, throw away the silly rot13 script that is included in the mode for some inexplicable reason. Reload modes in SEE, and you'll have a command that opens the current (Multi)Markdown document in Marked.
Amusingly, I inadvertently tried typing several things in this post using Markdown syntax (which Blogger doesn't use). It's very natural!
tell application "SubEthaEdit"
if not (exists path of front document) then
error "You have to save the document first"
set docpath to the path of the front document
set mdFile to POSIX file docpath
ignoring application responses
tell application "Marked" to open mdFile
displayName:"Preview with Marked",
toolbarTooltip:"Preview current document with Marked",
Edit: Made a minor change to the script. For reasons not entirely clear to me, the original form would hang on some files (naturally, none I tested before posting about it!), with SubEthaEdit waiting for a response from Marked. The
ignoring application responsestakes care of that.