No, we are not talking about food here.
It is just a fancy way to talk about something simple. It describes the transformation of a method that takes several arguments into a series of function that each take one of those arguments. Simple? Try on the exercise.
See? Simple. Some coding is worth a thousand words!
Writing the code that way has a few advantages.
For instance, you can decompose the function intopartially applied functions, likeadd2in the exercise. This example is simple, but imagine a complex function that takes a database connector and/or configurations. You could set those arguments, and then only reuse thepartially applied functionwhen needed, I like to call it a pre-configured operation.
I also like using it for aesthetics, It allows to use{ }like inr3in the exercise.
And you can have as many arguments chained that way, As well as also combinations, for instance the first block could have 2 arguments and then 1 and then 3 arguments. Use it wisely depending on your needs.