John McCarthy's videos are rare and it's great to see him talking. It's been said that LISP (alternatively J. McCarthy) borrowed the concept of functional closures from APL in mid 60's, that is McCarthy was not the original thinker of closures.
My (probably bad) knowledge of history is that the Lisps didn't do lexical scoping particularly well until Scheme. (Hopefully I don't have a false sense of "closures" vs. "lexical scoping".)
Yes I meant APL, not PAL. By functional closures, I tried to mean functions as first-class objects, i.e. ability to pass them as arguments or store them in data structures, etc.
I had read this in an article about Ruby, AFAIK. It was talking about Ruby (or alternatively "Matz") borrowing many principles from LISP and there the author had mentioned Lisp's functions being first-class objects were adopted from APL. I should find that article to clear the things up.
