CBCL: The Common Business Communication Language

Mon, 12 Dec 2016 23:05:28 +0000

I recently came across McCarthy’s CBCL paper on Hacker News. He presents a Lisp notation as a format for sharing requests between different software on different computers. He calls out

(PLEASE-RESERVE (EPSILON (x) 
  (AND
    (IS-FLIGHT x) 
    (DEPARTS MONDAY) 
    (ARRIVES (BEFORE WEDNESDAY)))))

where $\epsilon x$ is an operator maps a predicate to a value matching the predicate, and considers it an improvement on the “iota” definite description operator, which seems to be an operator that returns the unique value matching the predicate. It seems interesting to me that the unique match operator is not considered as useful as the arbitrary match operator – unique keys actually seem critical to a lot of my work with data models. Even more fascinating, though, is that this looks like an anonymous function!

Reading on traviscj/blog

CBCL: The Common Business Communication Language