CODEWITHSUNDEEP
clojure
swille
swille

Reputation: 841

Abstract structure of Clojure

I've been learning Clojure and am a good way through a book on it when I realized how much I'm still struggling to interpret the code. What I'm looking for is the abstract structure, interface, or rules, Clojure uses to parse code. I think it looks something like:

(some-operation optional-args)

optional-args can be nearly anything and that's where I start getting confused.

(operation optional-name-string [vector of optional args]) would equal (defn newfn [argA, argB])

I think this pattern holds for all lists () but with so much flexibility and variation in Clojure, I'm not sure. It would be really helpful to see the rules the interpreter follows.

Upvotes: 2

Views: 113

Answers (2)

Phil Cooper
Phil Cooper

Reputation: 5877

You are not crazy. Sure it's easy to point out how "easy" ("simple"? but that another discussion) Clojure syntax is but there are two things for a new learner to be aware of that are not pointed out very clearly in beginning tutorials that greatly complicate understanding what you are seeing:

  1. Destructuring. Spend some quality time with guides on destructuring in Clojure. I will say that this adds a complexity to the language and is not dissimilar from "*args" and "**kwargs" arguments in Python or from the use of the "..." spread operator in javascript. They are all complicated enough to require some dedicated time to read. This relates to the optional-args you reference above.

  2. macros and metaprogramming. In the some-operation you reference above, you wish to "see the rules the interpreter follows". In the majority of the cases it is a function but Clojure provides you no indication of whether you are looking at a function or a macro. In the standard library, you will just need to know some standard macros and how they affect the syntax they headline. (e.g. if, defn etc). For included libraries, there will typically be a small set of macros that are core to understanding that library. Any macro will to modify, dare I say, complicate the syntax in the parens you are looking at so be on your toes.

Clojure is fantastic and easy to learn but those two points are not to be glossed over IMHO.

Upvotes: 2

Maziyar Gerami
Maziyar Gerami

Reputation: 313

Before you start coding with Clojure, I highly recommend studying functional programming and LISB. In Clojure, everything is a prefix, and when you want to run and specific function, you will call it and then feed it with some arguments. for example, 1+2+3 will be (+ 1 2 3) in Clojure. In other words, every function you call will be at the start of a parenthesis, and all of its arguments will be follows the function name. If you define a function, you may do as follow:

(defn newfunc [a1 a2]
(+ 100 a1 a2))

Which newfunc add 100 and a1 and a2. When you call it, you should do this:

(newfunc 1 2)

and the result will be 103. in the first example, + is a function, so we call it at the beginning of the parenthesis. Clojure is a beautiful world full of simplicity. Please learn it deeply.

Upvotes: 1

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