Fabulous! A friend of mine was given the source of DoomEd by John Romero in order to try and clean it up and make it useful, like this, but unfortunately he ran out of time to do it, so Romero opened up the DoomEd source in its original state instead. I’ve passed this onto $friend who I think will be happy to know this was finally achieved.
For those interested in other Doom map editors, I caretake/maintain “WadC”, a tool for defining doom maps as functional programs, akin to LOGO: https://jmtd.net/wadc/
Very cool! My editor of choice was WadAuthor, and then Doom Builder: