Comment by kelas

ok, you have a point there. all 53 PDP-1s were "cheap" computers compared to IBM stuff (only $1M, adjusted) and used paper drum instead of punch cards. that was a nightmare to deal with, so people were buying IBM M typewriters to punch stuff in. Although Deutsch and Berkeley's LISP was in large part a copycat of IBM's LISP, people were indeed typing in LISP expressions in a REPL'ish manner. But if you ever saw a line of LISP, you can imagine what kind of "REPL" that was. "Miss one paren" comes to mind :)

APL\360 used a much more advanced selectric with a dedicated typeball, was designed for a machine of a totally different class, and could not be compared to literally kilometers of paper containing mostly mistyped parentheses. it was TRULY terse, expressive and interactive.

but yeah, PDP-1 hackers technically got there first - they had no choice :) check this out:

https://s3data.computerhistory.org/pdp-1/DEC.pdp_1.1964.1026...

6-7 Input and Output, System Operation is where the READ-EVAL-PRINT is indeed mentioned. but if you read the entire paragraph, and the next one ("if the system drops dead" lol) you'll agree that PDP-1 "REPL" was hell on earth, at the very end of the manual there are some really juicy REPL expressions :)

LISP was a torture compared to short and powerful APL notation.

less code less bug.