Symmetries in Boolean Scan

What happened

Array languages like APL are famous for using many pretty squiggles for representing built-in functions. These are called "primitives" and are different from user-defined functions, because the interpreters know about them and can do fancy optimizations with them, like recognizing special combinations [ 1 ] .

Summary assembled by rule from the sources below

Timeline

1. 16:12
   First appeared on LobstersLLobsters
2. 02:07
   Discussion started on Hacker NewsHHacker News

Sources