I'm working on http://mathdown.net (https://github.com/cben/mathdown).
Open, except for using Firebase.
Very much alpha at this stage - unsecure, sub-par highlighting, doesn't help with formatting, slow math rendering, if you don't bookmark all your documents you lose them...
I'm not hiding markup like Mango, except for latex formulas which I'm replacing with mathjax rendering - but they turn back into source the moment the cursor enters them.
It's inspired by emacs' auctex and more directly by https://play.google.com/store/apps/details?id=com.jamesmc.wr... (gratis but closed).
I'm also surprised almost nobody is taking the syntax-highlight-IS-the-preview approach to markdown editing.
I've heard the "plain markdown lets me focus on content and ignore formatting" idea, but I don't see how e.g. bigger font for headings is undesirable. It's not that variable fonts are hard to implement - CodeMirror already solved this: http://codemirror.net/demo/variableheight.html
(Variable fonts are not a pure win. They screw up indentation => I'm planning to use monospace for all leading spaces, as well as list bullets/numbers.)
I'm not hiding markup like Mango, except for latex formulas which I'm replacing with mathjax rendering - but they turn back into source the moment the cursor enters them. It's inspired by emacs' auctex and more directly by https://play.google.com/store/apps/details?id=com.jamesmc.wr... (gratis but closed).
I'm also surprised almost nobody is taking the syntax-highlight-IS-the-preview approach to markdown editing. I've heard the "plain markdown lets me focus on content and ignore formatting" idea, but I don't see how e.g. bigger font for headings is undesirable. It's not that variable fonts are hard to implement - CodeMirror already solved this: http://codemirror.net/demo/variableheight.html (Variable fonts are not a pure win. They screw up indentation => I'm planning to use monospace for all leading spaces, as well as list bullets/numbers.)