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
One difference is that conj accepts any number of arguments to insert into a collection, while cons takes just one: (conj ‘(1 2 3) 4 5 6) ; => (6 5 4 1 2 3) (cons 4 5 6 ‘(1 2 3)) ; => IllegalArgumentException due to wrong arity Another difference is in the class … Read more
You might like to read this paper by Richard Gabriel. It is a summary of the issues that the Lisp community were discussing in Lisp1 vs Lisp2. It’s a bit dense and slow moving in the first few sections, but is much easier to read by the time you get past section 5. Basically, Lisp1 … Read more
user=> (doc name) ————————- clojure.core/name ([x]) Returns the name String of a string, symbol or keyword. nil user=> (name :var_name) “var_name”
Compojure explained (to some degree) NB. I am working with Compojure 0.4.1 (here’s the 0.4.1 release commit on GitHub). Why? At the very top of compojure/core.clj, there’s this helpful summary of Compojure’s purpose: A concise syntax for generating Ring handlers. On a superficial level, that’s all there is to the “why” question. To go a … Read more
I’ve used Clojure for: Scraping web pages Shell scripts Building websites Playing around with OpenGL Writing async webservers HTML Templating Running parallel tasks (fetching multiple URLs and process in parallel) Playing around with real time audio Simulations That’s the practical / fun stuff. But Clojure has plenty of theoretical depth as well. Ideas that will … Read more
Transducers are recipes of what to do with a sequence of data without knowledge of what the underlying sequence is (how to do it). It can be any seq, async channel or maybe observable. They are composable and polymorphic. The benefit is, you don’t have to implement all standard combinators every time a new data … Read more
It is possible to create a single JAR file with all dependencies including the native JNI libraries for one or more platforms. The basic mechanism is to use System.load(File) to load the library instead of the typical System.loadLibrary(String) which searches the java.library.path system property. This method makes installation much simpler as the user does not … Read more
The difference is that for builds a lazy sequence and returns it while doseq is for executing side-effects and returns nil. user=> (for [x [1 2 3]] (+ x 5)) (6 7 8) user=> (doseq [x [1 2 3]] (+ x 5)) nil user=> (doseq [x [1 2 3]] (println x)) 1 2 3 nil … Read more
Just use :resource-paths in your project.clj file. I use it, e.g. to connect to Siebel servers. Just created a resources directory in my project directory and copied the jar files in there. But of course you could use a more generic directory: (defproject test-project “0.1.0-SNAPSHOT” :description “Blah blah blah” … :resource-paths [“resources/Siebel.jar” “resources/SiebelJI_enu.jar”]) Then from … Read more