In clojure terms, destructuring is taking apart a sequence and putting the pieces you care about into variables you can more easily work with. Destructuring involves square brackets that make it look like a vector, but it is really binding a variable from a given seq to a new variable. Let’s look at an example involving a function in Clojure.
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(defn request-printer [[site page user]] (println (str "site=>" site "\npage=>" page "\nuser=>" user))) (defn -main [& args] (request-printer ["example.com" "clojure.html" "clojure dude"])) |
Notice the -main function has three variables in a vector: a site address, a web page, and a user name. It is much easier in the new function to unpackage these variables form the vector and bind them to variables that have meaningful names, and then use the names.
The result is as follows.
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site=>example.com page=>clojure.html user=>clojure dude |
What if we have more values in the seq than values we intend to bind to? For example, below we added an additional index with the words “random stuff”.
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(defn request-printer [[site page user]] (println (str "site=>" site "\npage=>" page "\nuser=>" user))) (defn -main [& args] (request-printer ["example.com" "clojure.html" "clojure dude" "random stuff"])) |