Functions Are Things

In the functional programming paradigm, functions are things in their own right. And if functions are things, then they can be passed as input to other functions:

images/fn_input.png

Or they can be returned as the output of a function:

images/fn_output.png

Or they can be passed as a parameter to a function to control its behavior:

images/fn_parameter.png

Treating functions as things opens up a world of possibilities. It’s hard to get your head around at first, but you can already see that even ...

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