Ah, contains?… supposedly one of the top five FAQs re: Clojure. It does not check whether a collection contains a value; it checks whether an item could be retrieved with get or, in other words, whether a collection contains a key. This makes sense for sets (which can be thought of as making no distinction … Read more
Yes, here is main project I am aware of: https://github.com/remvee/clojurehelloandroid And here is a little tutorial http://riddell.us/ClojureAndAndroidWithEmacsOnUbuntu.html though I would not be surprised if this tutorial is outdated, as it was over a year ago when I played with the code following this tutorial, and remvee’s code has since been updated. EDIT: see the update … Read more
1.: The reason this doesn’t work is (more or less) given on the page you linked: It is an error if there is no global var named by the symbol […] And: […] A lookup is done in the current namespace to see if there is a mapping from the symbol to a var. If … Read more
Let me move the whitespace in your code so it’s obvious to you what is wrong: (defn factors [x] ((loop [n x i 2 acc []] (if (prime? n) (conj acc n) (if (zero? (mod n i)) (recur (/ n i) 2 (conj acc i)) (recur n (inc i) acc)))))) You see that weird (( … Read more
Here’s my take on it. I made a point of only using Clojure data structures to see how that would work out. Note that it would have been perfectly usual and idiomatic to take a blocking queue from the Java toolbox and use it here; the code would be easy to adapt, I think. Update: … Read more
Just use the ones in Clojure directly. While obviously you might not want to use the language it’s self, you can still use the persistent collections directly as they are all just Java classes. import clojure.lang.PersistentHashMap; import clojure.lang.IPersistentMap; IPersistentMap map = PersistentHashMap.create(“key1”, “value1”); assert map.get(“key1”).equals(“value1”); IPersistentMap map2 = map.assoc(“key1”, “value1”); assert map2 != map; assert … Read more
I normally call (keys (ns-publics ‘foo)) to list Vars exported by the namespace foo; e.g. for clojure.contrib.monads this returns (defmonad censor m-when-not m+write+m maybe-m maybe-t …) (the … stands for quite a lot more). More generally, there’s a bunch of functions whose names start in ns- which list Vars by namespace, with certain additional criteria … Read more
doall is all you need. Just because the seq has type LazySeq doesn’t mean it has pending evaluation. Lazy seqs cache their results, so all you need to do is walk the lazy seq once (as doall does) in order to force it all, and thus render it non-lazy. seq does not force the entire … Read more
I like your reduce version just fine. I think it’s idiomatic. Here’s a version using list comprehension anyways. (defn foo [m f] (into {} (for [[k v] m] [k (f v)])))
Your problem statement seems a little vague, so I’ll solve a simplified version of the problem. Keep in mind that a macro is a code-translation mechanism. That is, it translates the code that you wish you could write into something that is acceptable by the compiler. In this way, it is best to think of … Read more