There was once a post here on HN (long enough ago that I couldn't find it just now) that was a text editor that didn't allow anything other than adding text. Yo

There was once a post here on HN (long enough ago that I couldn't find it just now) that was a text editor that didn't allow anything other than adding text. You couldn't go back, delete, etc. And its purpose was exactly what you are asking for - a productivity tool that let you get your ideas written out without getting sidetracked by tweaking, and you could then use another editor at another time to polish it up. At the time, I thought it would be cool to make that a particular mode in an editor - kinda like running vi in INSERT mode without readline, but additionally without all the ^Control characters showing up whenever you accidentally try to do something other than typing straight ahead. Hopefully my description will jog someone's memory.