To add to this, a quote from an article about the editor ed:

It’s important to realize that in ed you were usually editing a file you had already printed beforehand. If you only wanted to fix a few small things in a multi-page listing, you simply entered the corrections in ed on the relevant lines, added something here and there, and at the same time you would just write the simple minor fixes directly into the printout by hand-without having to tediously retype everything.

You had the files on paper, which is a very pleasant and ergonomic medium for reading. You can literally surround yourself with it, cover your desk, and easily move your eyes between dozens of functions. If you learn to keep order and stay oriented in that mountain of paper, you can be very effective.

Moreover, from an ergonomic point of view you wouldn’t be doing badly at all. Printed paper in natural light is definitely easier on the eyes than low-refresh-rate screens in the years that followed. Paper lets you quickly add notes, sketch a little graph, basically work in a very natural way - one people were used to back then from the moment they first held a crayon.

Most of the time a programmer isn’t writing code but reading it. In that respect, people back then may actually have had it better than we do today. When it did come to writing, the only truly more complicated part was essentially making corrections. The history of everything you’d done was right there on paper. I don’t want to idealize the way they worked back then, but all of this explains how they were able to work effectively even with such primitive tools.

> You had the files on paper, which is a very pleasant and ergonomic medium for reading. You can literally surround yourself with it, cover your desk, and easily move your eyes between dozens of functions. If you learn to keep order and stay oriented in that mountain of paper, you can be very effective.

That only works if your printouts aren’t too long, and contain the majority of the logic in your programs.

Today, the latter rarely is the case. Maybe, we need a way to print code with t selected documentation of called functions added?

That ‘selected’ would be a tricky problem, though. What I need to understand the code may not be what you need, or what I need a month from now.

This is why a lot of people like Vim.When you can target precisely where you want to edit, it becomes effortless instead of being a chore. With windows (panes), you can easily arrange buffer (contents of files mostly) spatially like you would on a desk. Even with vi (which lacks windows), you can make do with marks (bookmarks on lines)

Same with Emacs. You bring a whole toolset for each buffer (major and minor modes). And then you got to editing. Like imenu for automatically finding interesting places like functions, structure,… declarations, outline mode that use regex to provide an outline tree that you can then edit, view-mode that adapt the keybinds for scrolling,…