The Lisp Implementafion for the PDP-1 Computer [pdf]

Peter Deutsch finished this when he was 17 years old.<p><a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;L._Peter_Deutsch" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;L._Peter_Deutsch</a>

Some more info about the PDP-1 asm here. <a href="https:&#x2F;&#x2F;www.masswerk.at&#x2F;spacewar&#x2F;inside&#x2F;pdp1-instructions.html" rel="nofollow">https:&#x2F;&#x2F;www.masswerk.at&#x2F;spacewar&#x2F;inside&#x2F;pdp1-instructions.ht...</a>

Note that, cf. a recent discussion about REPLs, this may be the first known (at least published) REPL.

Pg. 4: “Doing CDR of an atom is permissible and will get the atom’s property list. Doing a CAR of an atom may very easily wreck the system.” :-)