Defining a Go iterator is similar to defining a Python decorator that takes an argument. Both involve defining a function that returns another function, with th

Defining a Go iterator is similar to defining a Python decorator that takes an argument. Both involve defining a function that returns another function, with the inner function having another function as its parameter. This isn’t a particularly difficult concept, but manipulating functions in this way does feel unusual in such heavily-procedural languages. This has two downsides: * Programmers who only use those languages are unfamiliar with the concept, and * The languages’ syntaxes aren’t designed to make it particularly clear.