We detached this subthread from https://news.ycombinator.com/item?id=14348231 and marked it off-topic. I assume it's in reference to McCarthy being surprised at Steve Russell's implementation of eval, but I'd be shocked if he actually said it was impossible.

He did not say these words, that was indeed what I was referring to.

This has to be the most possible thing I've ever seen labeled impossible. Lisp 1.5 has extensive documentation and we have program listings to test against. Nothing else is really needed.

Edit: This joke flew way over my head. [1]

[1] "Steve Russell said, look, why don't I program this eval..., and I said to him, ho, ho, you're confusing theory with practice, this eval is intended for reading, not for computing." -- McCarthy (http://www.paulgraham.com/icad.html)

My bad, and thanks

Rubbish.

Lisp 1.5 wasn't just a theory, and ran on the PDP-1, thanks to Peter Deutsch.

Here's a copy that can run on an IBM 7094 emulator. [0]

Several people have made interpreters over the years. [1][2][3]

[0] http://www.sonoma.edu/users/l/luvisi/

[1] http://mentallandscape.com/Lisp.htm

[2] https://www.oskarth.com/lisp-interpreter/

[3] https://www.cl.cam.ac.uk/~mom22/tphols09-lisp.pdf

Still not possible.

It isn't possible to write an interpreter for this language... When the canonical form was an interpreter written by a high school kid using the manual for the language ...

You're going to need to explain some more.

You are tense my dear. I know pretty well about this (as one can read on my profile).

ps: but I'm sorry it wasn't clear I was facetious in the first place.

I have written many a Lisp interpreter myself.

Lisp 1.5 uses F-EXPR, quoteval, and the basic forms from LISP. Nothing difficult there.

But again, something that has already been done cannot be labelled as impossible.

If you provide no further proof for your somewhat outrageous claim, then your statements are no more than a tale told by an idiot, full of sound and fury. Signifying nothing.

Edit: Sarcasm has problems translating across textual barriers. Try denoting future comments as such, or to avoid downvotes, avoid them altogether on HN.