Firefly is a new general purpose programming language that tries to achieve convenience and safety at the same time, by using pervasive dependency injection. There is no global access to the file system, the network, other processes or devices. Instead, you access these through a system object that is passed to the main function, which in turn can pass this object to other methods. The idea is to give the programmer fine grained control over which parts of the code can access what (Log4Shell anybody?), without introducing monads or other explicit effect tracking.

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