In functional programming, continuation-passing style (CPS) is a style of programming in which control is passed explicitly in the form of a continuation. This is contrasted with direct style, which is the usual style of programming
A function foo written in CPS style takes a callback bar, and bar is executed as the return value of foo. The callback bar is called a continuation function. The continuation function is a tail call.
Gleam
Gleam has an interesting syntactic sugar around this pattern with the use keyword:
// standard callback
f(a, fn(b) { g(b) })
// with use
use b <- f(a)
g(b)
Sort of an inverted callback. A callback function is a function definition stored in variable for later execution when its arguments have been computed; CPS stores a set of arguments that can be bound to a function, and that function will be executed when the arguments are calculated.