@vidak I added a ‘text editor’ to Radio Shack BASIC. That is, you could get back the previous input line and edit it, like you can with history in a modern shell.

My Trash-80 had a homebrew lowercase modification, too. We took a chance my design would work, and it did. Largely using spare gates that were on the board.

The text editor I used was one I adapted from 8080 code in Byte or Dr. Dobbs magazine. It worked by a cursor gap. So did my BASIC line editor (implemented in Z80).