[kelas]

> seems to disagree

no, actually i think Wikipedia got it right:

  "The 1974 Maclisp reference manual by David A. Moon attests "Read-eval-print loop" on page 89, but does not use the acronym REPL.[7]
  Since at least the 1980s, the abbreviations REP Loop and REPL are attested in the context of Scheme.[8][9]"

The first APL interpreter was implemented on System/360 in 1965. Iverson got a Turing in 1979.

[BoiledCabbage]

> In 1964, the expression READ-EVAL-PRINT cycle is used by L. Peter Deutsch and Edmund Berkeley for an implementation of Lisp on the PDP-1.

If you're arguing that "Read-Eval-Print cycle" doesn't count as REPL, then it pretty strongly undercuts your argument that "dialog approach" is.

And 1964 predates APL implementation.

[kelas]

> If you're arguing that "Read-Eval-Print cycle" doesn't count as REPL, then it pretty strongly undercuts your argument that "dialog approach".

no, thankfully, it doesn't, and here's why. as i elucidated above, PDP-1 was indeed a revolutionary "el cheapo" computer, which DEC managed to ship over 50 units of. it gave birth to hacker culture, just because it had to be hacked with all kinds of peg legs in order to be useful. now, to the point:

1. PDP-1 is mostly remembered for Spacewar!, a groundbreaking space combat game invented by a dude who also coincidentally invented large parts of LISP while on IBM payroll.

2. APL, after its debut in 1965-1966, had its first official application to teach formal methods in systems design at NASA Goddard Center.

My point should be obvious, but just in case:

in our line of work (between sessions on Hacker News) we are sometimes faced with the concept of "production" (usually on Friday afternoons). this idea really matters. it makes all the difference between fooling around and the real deal.

therefore, as it must follow, and as i mentioned much earlier, APL was and remains the very first real REPL system, although they didn't really use that terminology. all i meant is that in 21st century people take Chrome's devconsole, ipython, node, zsh for granted. with completions, hints, all that.

(in APL'esque family, by the way, there's hardly anything to hint or auto-complete. mathematics doesn't work that way. by the way, not coincidentally, one of the most successful modern descendants of APL is called Wolfram Mathematica)

are we on the same page?

[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.