Hacker News new | ask | show | jobs
by vilhelm_s 2500 days ago
Oh, I think you're right, Scheme was at least the first lexically scoped Lisp.

Wikipedia says

> The concept of closures was developed in the 1960s for the mechanical evaluation of expressions in the λ-calculus and was first fully implemented in 1970 as a language feature in the PAL programming language to support lexically scoped first-class functions.

> PAL, the Pedagogic Algorithmic Language, is a programming language developed at the Massachusetts Institute of Technology in around 1967 to help teach programming language semantics and design. It is a "direct descendant" of ISWIM and owes much of its philosophy to Christopher Strachey.