Using threading macros

Threading macros are the cherry on the pie of your Clojure code. We use them all the time, and for one very simple reason: they make your code more readable. We can think of threading macros as a way to directly see how the data flows through our well-crafted functions.

Threading macros, as the name suggests, are macros. The code you write is being rearranged before being compiled and evaluated.

In this short section, we will see how to use the two threading macros, -> and ->>, so that you can use and abuse them while having some Clojure fun.

This will also be used as a bridge to learn how to write our own macros in the following two recipes.

Finally, we will also see how this is used in context for a full-fledged Apache Spark integration.

Getting ready

For this recipe, nothing but a plain Clojure REPL is needed.

How to do it...

In this short section, we will review the main threading macros of the Clojure language.

Introducing the -> macro

In pseudo-code, we can...