generators - The Rust Unstable Book

generators The tracking issue for this feature is: #43122 The generators feature gate in Rust allows you to define generator or coroutine literals. A generator is a "resumable function" that syntactically resembles a closure but compiles to much different semantics in the compiler itself. The primary feature of a generator is that it can be suspended during execution to be resumed at a later date.

[tanakh]

ひとまずnightlyに実装が入ったらしい