[qohen]

...these things were mostly written(and rewritten till perfection) on paper first and only the near-end program was input into a computer with a keyboard.

Not if you were working in a high-level language with an interpreter, REPL, etc. where you could write small units of code that were easily testable and then integrated into the larger whole.

As with Lisp.

And Prolog.

[kamaal]

Personal computers are a thing from the late 1980s.

Even then PC use in businesses was fairly limited.

Prolog appeared in 1972.

Either way before the PC, Programming was nothing like it is today. It was mostly a Math discipline. Math is done on paper.

[qohen]

The following is from David H.D. Warren's manual for DEC-10 Prolog, from 1979 [0]. It describes how Prolog development is done interactively, by being able to load code in dynamically into an interpreter and using the REPL -- note that the only mention of using paper is if the developer wants to print out a log of what they did during their session:

Interactive Environment Performance is all very well. What the programmer really needs is a good inter-active environment for developing his programs. To address this need, DEC-10 Prolog provides an interpreter in addition to the compiler.

The interpreter allows a program to be read in quickly, and to be modified on-line, by adding and deleting single clauses, or by updating whole procedures. Goals to be executed can be entered directly from the terminal. An execution can be traced, interrupted, or suspended while other actions are performed. At any time, the state of the system can be saved, and resumed later if required. The system maintains, on a disk file, a complete log of all interactions with the user's terminal. After a session, the user can examine this file, and print it out on hard copy if required.

[0] https://softwarepreservation.computerhistory.org/prolog/edin...