- [ ] Make sure things are at least a little faster again for large files.
   - In a perfect world, we'd only re-highlight the paragraphs that have changed...
   - As a workaround, we could either highlight code blocks asynchronously, or do it when typing stops?
- [ ] Link checker
- [ ] Come up with a good (defined) scheme for fence names
- [ ] Auto-completion/formatting using SourceKitten?
- [ ] "Halt on Error" checkmark menu item that halts when an error happens
- [x] Have a way to mark certain swift blocks as non-executable
- [ ] Have a way to mark a block (or better: a line) as expecting to yield a compiler error.
- [ ] Have multiple "sessions" within a file
- [ ] Search (and replace)
- [ ] Have an (optional?) clickable outline-view of the document on the left-hand-side of the splitview.
- [ ] Parse yaml preamble?
- [ ] Allow for a way to have "rich" results. Maybe we could do something with HTML?
- [ ] Allow for multi-line expressions. Maybe we could simulate the down arrow somehow.
- [ ] Spell checker
- [ ] Highlight nested code blocks (e.g. in blockquotes)
- [x] Have a way to go back to the source code from an error in the console (could be a link)
- [x] Something is wrong with conforming to certain protocols (e.g. list and ExpressibleByArrayLiteral).