"Context" manipulation is one of big topic and there are many related terminologies (academic, language/implementation specific, promotion terminologies). In fact, there is confusing. In few minutes I remember the following related words and it is good CS exam to describe each :p Thread (Ruby) Green thread (CS terminology) Native thread (CS terminology) Non-preemptive thread (CS terminology) Preemptive thread (CS terminology) Fiber (Ruby/using resume/yield) Fiber (Ruby/using transfer) Fiber (Win32API) Generator (Python/JavaScript) Generator (Ruby) Continuation (CS terminology/Ruby, Scheme, ...) Partial continuation (CS terminology/ functional lang.) Exception handling (many languages) Coroutine (CS terminology/ALGOL) Semi-coroutine (CS terminology) Process (Unix/Ruby) Process (Erlang/Elixir) setjmp/longjmp (C) makecontext/swapcontext (POSIX) Task (...)

Generator based control flow goodness for nodejs and the browser, using promises, letting you write non-blocking code in a nice-ish way.

you can use whatever control flow block you like instead of return (e.g. an if, or throw, etc)

Throw it's a more elegant way to use an exception-like system as a control flow.

Each step receives the return value of its predecessor. The return value decides about what next step is called.

While you could program this little piece of logic and flow yourself using a bunch of Ruby methods along with a considerable amount of ifs and elses, and maybe elsif, if you’re feeling fancy, a Trailblazer activity provides you a simple API for creating such flow without having to write and maintain any control code. It is an abstraction.

found that using only the Pascal-provided control structures, the correct solution was given by only 20% of the subjects, while no subject wrote incorrect code for this problem if allowed to write a return from the middle of a loop.

Better control over flow of our application: more ways to add branching

The DSL has a weaker control over the program’s flow — we can’t have conditions unless we add a special step

Here, when x is a Boolean value then the section tag acts like an if conditional, but when x is an array then it acts like a foreach loop.