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    <p>I've been using Clojure for two years now and the only time I ever used monads was as an exercise to show that it could be done. I've never needed them for "real" code.</p> <p>Monads are much more common in Haskell because:</p> <ul> <li>They are the idiomatic way of handling stateful computations. In Clojure, you typically handle state with <a href="http://clojure.org/refs" rel="noreferrer">managed references</a>, so monads aren't needed nearly as much in Clojure. </li> <li>Likewise for IO: Clojure allows you to do IO directly without declaring it in your type, so you don't need the IO monad.</li> </ul> <p>My suggestion would be to focus on standard functional programming in Clojure. Unless you see that you really <em>need</em> monads then I wouldn't invest too much time in trying to bring them in.</p> <p>Macros are a slightly different issue: they are for compile-time code generation and extensions to the language syntax (which might include DSLs, although DSLs don't necessarily need macros). I use macros when both of the following are true:</p> <ol> <li>I want to extend the language syntax in a way that significantly improves my ability to address a particular problem domain. </li> <li>I <em>can't</em> get the same functionality with normal functions / function composition. Normal functions should be your first choice if possible: they are usually simpler to write and maintain.</li> </ol> <p>P.S. If you are genuinely interested in monads for Clojure, here are two videos I personally found quite good:</p> <ul> <li><a href="http://vimeo.com/20717301" rel="noreferrer">http://vimeo.com/20717301</a> (Brian Marick's excellent visual explanation of monads)</li> <li><a href="http://www.infoq.com/presentations/Monads-Made-Easy" rel="noreferrer">http://www.infoq.com/presentations/Monads-Made-Easy</a></li> </ul>
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    1. POIn clojure, when should we use a monad instead of a macro and vice-versa?
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    1. COJust to add... in clojure monads are implemented using macros. So monads in clojure is just a library where as in other languages they has to be part of the language
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    2. COIn Haskell, the only part of monads that are "part of the language" (as opposed to the standard library) is the convenient do notation, and their use for I/O.
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    3. CO@Ankur, that makes no sense whatsoever. A monad abstraction is fully defined by two functions. If you are using a dynamically typed language, there's nothing stopping you from using this abstraction. If your language is statically and nominally typed, you'll need either higher kinds of first class modules to reliably represent this abstraction.
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