[sstephenson]

It is not impossible. It just takes a lot of time and effort. It took two developers around 18 months to build Trix.

The readme explains how our approach is different from other WYSIWYG editors. (Most others are just toolbars that call execCommand.)

[lobster_johnson]

Did you look at ProseMirror? http://prosemirror.net/

[sstephenson]

Yes, of course we've seen ProseMirror. It looks quite nice.

By the time we first heard of it several months ago, the bulk of Trix had already been written.