> when I finally understood that the half page of code on the bottom of page 13 of the Lisp 1.5 manual was Lisp in itself
Even histories of Lisp often don't emphasize this: Lisp was not, originally, invented as a programming language. It was a notation for describing the mathematics of computation. A variant of lambda calculus that could describe itself compactly.
The fact that eval could actually be implemented, was an accidental discovery. To quote McCarthy:
> 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. But he went ahead and did it. That is, he compiled the eval in my paper into IBM 704 machine code, fixing bugs, and then advertised this as a Lisp interpreter, which it certainly was.
it was developed as a programming language from day one. It just had no such evaluator, until they came up with the idea and implemented it. There were Lisp programs already before that.
Even histories of Lisp often don't emphasize this: Lisp was not, originally, invented as a programming language. It was a notation for describing the mathematics of computation. A variant of lambda calculus that could describe itself compactly.
The fact that eval could actually be implemented, was an accidental discovery. To quote McCarthy:
> 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. But he went ahead and did it. That is, he compiled the eval in my paper into IBM 704 machine code, fixing bugs, and then advertised this as a Lisp interpreter, which it certainly was.
https://web.archive.org/web/20050405213907/http://www8.infor...