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I was going to say I had heard that this was the intention of Lisp's creators, then I thought I had better check, and immediately found this: Lisp had assignme

I was going to say I had heard that this was the intention of Lisp's creators, then I thought I had better check, and immediately found this: Lisp had assignments and goto before it had recursion, and started as a dialect of Fortran! It was only later that Lisp programmers investigated the benefits of pure functions. Lisp was not based on lambda calculus, but rather Kleene's work on recursive functions. At the time, McCarthy had heard of lambda calculus but had not yet studied it! https://crypto.stanford.edu/~blynn/lambda/lisp.html https://crypto.stanford.edu/~blynn/lambda/lisp.html

kazinator 4y ago
The list processing in Lisp was inspired by FLPL: Fortran List Processing Language. This was more like a library of Fortran routines than a language, but in 1958 the term library for routines of code didn't even exist. Making new words of any kind was language development. FLPL already used the CAR and CDR terminology in its naming, with extra characters: XCARF and XCDRF (and others). The "extract CAR function" and "extract CDR function".
bmitc 4y ago
As far as I understand, McCarthy was into Godel, recursive functions, mathematics, and AI in trying to create Lisp to study these, not so much computability and the like. I think that's at least one line of thinking that causes people to say that McCarthy discovered Lisp instead of inventing it.