As I write this, word has it that John McCarthy passed away yesterday. Tech Crunch is reporting this as fact, citing Hacker News, which in turn cites a single tweet as the ultimate source. So the only authority we have, for now, is one person on Twitter, and we don’t know what relation she has to McCarthy.
[Update: More recent comments on Hacker News corroborate the story. Also, the twitterer cited above, Wendy Grossman, said McCarthy's daughter called her.]
I also have an unsubstantiated story about John McCarthy. I believe I read the following some time ago, but I cannot remember where. If you know of a reference, please let me know. [Update 2: Thanks to Leandro Penz for leaving a link to this article by Paul Graham in the comments below.]
As I recall, McCarthy invented Lisp to be a purely theoretical language, something akin to lambda calculus. When his graduate student Steve Russell spoke of implementing Lisp, McCarthy objected that he didn’t intend Lisp to actually run on a physical computer. Russell then implemented a Lisp interpreter and showed it to McCarthy.
Steve Russell is an unsung hero who deserves some of the credit for Lisp being an actual programming language and not merely a theoretical construct. This does not diminish McCarthy’s achievement, but it does mean that someone else also deserves recognition.