clojure classpath(?) troubles loading code and dependencies with leiningen

Question

I'm a Clojure and JVM beginner, and the build tools are a bit confusing to me, so forgive the stupidity I'm about to carry out. I don't actually know what a "classpath" is... I just want a Lisp with lots of libraries!

But I'm trying to do a write a simple little bit of text-mining code in Clojure, and I don't seem to be able to get things working.

There are two problems, and I think they're related, both probably to this classpath thing from javaland that none of the introductory Clojure books seem to explain.

I started the project with lein new and my project.clj has the following dependencies:

 :dependencies [[org.clojure/clojure "1.6.0"] 
                 [clj-fuzzy "0.1.8"]
                 [snowball-stemmer "0.1.0"]
                 [net.mikera/core.matrix "0.50.0"]])

and the relevant ns call from my core.clj is as follows:

(ns blabber.core 
  (:require 
    [clojure.string :refer [lower-case split]]
    [clojure.walk :refer [keywordize-keys]]))

My directory structure is the default setup leiningen uses for a new library.

First problem :

I gather from this prior SO that if things are set up right, I shouldn't need to call (load-file "src/blabber/core.clj") in the repl before calling (use 'blabber.core) in order to get at code I just wrote. (I'm firing up the lein repl from the src/blabber directory in bash). But when I fire up the repl, use fails unless I call load-file first. So does that mean my classpath is set up wrong somehow? And how does one fix such a thing?

Second problem :

Ok, so now I'm trying to actually use core.matrix. First line of my core.clj changed to:

(ns blabber.core 
  (:require 
    [clojure.string :refer [lower-case split]]
    [clojure.walk :refer [keywordize-keys]]
    [clojure.core.matrix :refer [dataset]]))

When I first started the repl with this project.clj but without the :require to core.matrix, leiningen happily fetched core.matrix: Retrieving net/mikera/core.matrix/0.50.0/core.matrix-0.50.0.jar from clojars

However, after including the :require to core.matrix in the actual code and starting up the repl again, at the repl I call (load-file "src/blabber/core.clj") , and get the following error:

CompilerException java.io.FileNotFoundException: Could not locate clojure/core/matrix__init.class or clojure/core/matrix.clj on classpath: , compiling:(/Users/pauliglot/github/blabber/src/blabber/core.clj:1:1)

I'm using Leiningen 2.5.1 on Java 1.8.0_45. And I'm just following the getting started guide for core.matrix.

So what happened? Why can't the JVM find any of my stuff? Save me? Thanks!

If it helps, here's a dump of the output of lein classpath

/Users/pauliglot/github/blabber/test:/Users/pauliglot/github/blabber/src:/Users/pauliglot/github/blabber/dev-resources:/Users/pauliglot/github/blabber/resources:/Users/pauliglot/github/blabber/target/classes:/Users/pauliglot/.m2/repository/clj-fuzzy/clj-fuzzy/0.1.8/clj-fuzzy-0.1.8.jar:/Users/pauliglot/.m2/repository/snowball-stemmer/snowball-stemmer/0.1.0/snowball-stemmer-0.1.0.jar:/Users/pauliglot/.m2/repository/org/clojure/tools.macro/0.1.5/tools.macro-0.1.5.jar:/Users/pauliglot/.m2/repository/clojure-complete/clojure-complete/0.2.3/clojure-complete-0.2.3.jar:/Users/pauliglot/.m2/repository/org/clojure/google-closure-library-third-party/0.0-20140226-71326067/google-closure-library-third-party-0.0-20140226-71326067.jar:/Users/pauliglot/.m2/repository/com/google/protobuf/protobuf-java/2.4.1/protobuf-java-2.4.1.jar:/Users/pauliglot/.m2/repository/org/clojure/google-closure-library/0.0-20140226-71326067/google-closure-library-0.0-20140226-71326067.jar:/Users/pauliglot/.m2/repository/org/ mozilla/rhino/1.7R4/rhino-1.7R4.jar:/Users/pauliglot/.m2/repository/org/json/json/20090211/json-20090211.jar:/Users/pauliglot/.m2/repository/net/mikera/core.matrix/0.50.0/core.matrix-0.50.0.jar:/Users/pauliglot/.m2/repository/com/google/javascript/closure-compiler/v20131014/closure-compiler-v20131014.jar:/Users/pauliglot/.m2/repository/com/google/code/findbugs/jsr305/1.3.9/jsr305-1.3.9.jar:/Users/pauliglot/.m2/repository/org/clojure/clojurescript/0.0-2202/clojurescript-0.0-2202.jar:/Users/pauliglot/.m2/repository/args4j/args4j/2.0.16/args4j-2.0.16.jar:/Users/pauliglot/.m2/repository/org/clojure/tools.nrepl/0.2.6/tools.nrepl-0.2.6.jar:/Users/pauliglot/.m2/repository/com/google/guava/guava/15.0/guava-15.0.jar:/Users/pauliglot/.m2/repository/org/clojure/clojure/1.6.0/clojure-1.6.0.jar:/Users/pauliglot/.m2/repository/org/clojure/tools.reader/0.8.3/tools.reader-0.8.3.jar:/Users/pauliglot/.m2/repository/org/clojure/data.json/0.2.3/data.json-0.2.3.jar

Edit Here's the directory tree: | blabber |-doc |-resources |-src |---blabber |-target |---classes |-----META-INF |-------maven |---------blabber |-----------blabber |---stale |-test

and all my code is in blabber/src/blabber/core.clj

Answer 1

A classpath is a Java concept; Leiningen should set up the classpath correctly. What I suspect is that there's a mismatch between the directories, filenames, or namespace declarations. The file path should be <name passed to 'lein new'>/src/blabber/core.clj. It wasn't clear from what you wrote whether that's the case. Try running lein deps first, too, but you shouldn't need to do that. This and lein repl are usually run from the directory, ie the project root directory. You might need :source-paths or :main in project.clj, but I don't think so.

(use 'clojure.core.matrix) should work. Works for me, eg with

(defproject blabber "0.1.0-SNAPSHOT"
  :dependencies [[org.clojure/clojure "1.8.0"]
  [net.mikera/core.matrix "0.50.0"]]).