The Reynolds paper is one of my favorites. It was re-typeset in 1998 making it a lot easier to follow the math [0]. It's fun to compare it to a copy of the original from 1972 [1].

Philip Wadler had this to say about the paper: "Certain papers change your life. McCarthy's 'Recursive Functions of Symbolic Expressions and their Computation by Machine (Part I)' (1960) changed mine, and so did Landin's 'The Next 700 Programming Languages' (1966). And I remember the moment, halfway through my graduate career, when Guy Steele handed me Reynolds's 'Definitional Interpreters for Higher-Order Programming Languages' (1972)."[2] This is how I discovered it I believe.

The paper is exceedingly approachable. It was so well written that I immediately purchased a used copy of Reynolds' book on programming languages (which I did not have as easy time with compared to the paper - and still remains unfinished on my bookshelf).

When they republished the paper in 1998, Reynolds wrote about how the paper came to be [3], and I believe about the discoveries of continuations [4].

I recently implemented Reynold's meta-circular interpreter in TypeScript and serialized the abstract syntax into JSON. Coincidentally, a few days later I saw a post on HN something about "executable JSON" or some such "programming language" that the creator was very proud of making it into a product of sorts. (found it... JSON Logic: https://news.ycombinator.com/item?id=27306263). Queue Greenspun's tenth rule. I chuckled as I looked at the JSON Logic syntax knowing that a little Reynold's interpreter with its AST serialized to JSON is infinitely more powerful and extensible (allowing higher-order functions and such). I highly recommend anyone reading this to write the 50 or so lines of TypeScript necessary to implement Reynold's meta-circular interpreter (EXTREMELY EASY and nearly identical line-for-line to the 1998 paper, only in TypeScript instead of lambda calculus).

Good stuff.

[0] [PDF] https://surface.syr.edu/cgi/viewcontent.cgi?article=1012&con...

[1] [PDF] https://homepages.inf.ed.ac.uk/wadler/papers/papers-we-love/...

[2] https://homepages.inf.ed.ac.uk/wadler/topics/history.html#de...

[3] [PDF] https://homepages.inf.ed.ac.uk/wadler/papers/papers-we-love/...

[4] [PDF] https://homepages.inf.ed.ac.uk/wadler/papers/papers-we-love/...