Anytime I fire up a fresh REPL I always get the same message, namely
#<FileNotFoundException java.io.FileNotFoundException: Could not locate test_app/core_init.class or test_app/core.cljon classpath:>
The namespace I've been using is ns test-app.core
The REPL still continues to come up and I am able to execute code with it. I am just unsure if this will lead to future problems, such as trying to work with incanter or other libraries.
Does your project.clj contain the following line, per chance?
...
:main test-app.core
...
Leiningen will try to switch into that namespace before showing the REPL to you. If it cannot find it, you'll see the error you mentioned. Now, the reason it cannot find it is another topic to explore, so first make sure that this is how your directory structure looks like:
.
|-- project.clj
|-- src
|-- test_app
|-- core.clj
If it does, I guess it's time to post Leiningen and Java versions (and ideally your project.clj) to let SO try to tackle this miraculous REPL. :)
Edit: The solution to this problem would - if any of the above suggestions match your case - of course be to either remove the :main line from your project file or to adjust the directory structure.
There needs to be a core.clj file in the folder named test_app in your project structure.
Basically, the file name should apply the naming towards whatever you've declared in your ns form.
As the Clojure Documentation FAQ says,
In order to use a Java class or Clojure namespace in your program,
that class or namespace must be "on the classpath," that is, inside a
directory or JAR file listed in the classpath.
Related
I am trying to setup proto-repl atom-editor package and apparently it needs a file user.clj to exist somewhere - which I guess is some leiningen's init file.
Where should I create this file?
Clojure will load the file user.clj from your class path if it is found. In a default leinengen project src/ will be on the class path, so if you create src/user.clj the contents of that file will be loaded in the context of the user namespace.
user is the default namespace for the clojure repl, but some leiningen projects override this. In order to access definitions in user.clj you will need to either pull user into scope (using require or use) or make sure that user is your starting namespace.
See the Proto REPL demo project https://github.com/jasongilman/proto-repl-demo/blob/master/dev/user.clj for an example of how to setup user.clj You should also add a dependency on clojure.tools.namespace in the project.clj https://github.com/jasongilman/proto-repl-demo/blob/master/project.clj
I just pushed some changes to Proto REPL last night to improve this area but you'll still benefit from having one setup.
According to the proto-repl page, it might use some functions from user namespace when reloading code in REPL (reset function) but it shouldn't be required.
You might want to take a look at the proto-repl demo project to see the more advanced setup.
I need to share a namespace between my Clojure (Garden) and my ClojureScript (Reagent).
Currently the project folder looks like this:
src/
clj/
name/
css.clj
cljs/
name/
core.cljs
cljc/
name/
config.cljc
The config.cljc file has the following namespace: (ns name.config).
I've tried to reference this namespace from inside clj/name/css.clj with a require.
(ns name.css
(:require [name.config :as config]))
However, this results in a compile error from Garden.
Caused by: java.io.FileNotFoundException: Could not locate name/config__init.class or name/config.clj on classpath.
I guess it's not even checking for cljc files.
I added "src/cljc" to the :source-paths vector in project.clj and :garden :builds but I get the same error even after restarting the build processes.
I see this behaviour on Clojure 1.7.0 and 1.8.0.
It might also be worth mentioning that it works without issues in ClojureScript (with Figwheel handling the build). I can require and use the new namespace without problems.
It seems like I must be missing something really simple, because none of the documentation around .cljc files even mentions requiring them.
Check if you’re using Clojure 1.7 or above in your project.clj. This error message:
Caused by: java.io.FileNotFoundException: Could not locate name/config__init.class or name/config.clj on classpath.
indicates that you’re using Clojure 1.6 or below, as those versions of Clojure only know to look for .class or .clj files.
I got this same error when I moved a file from .clj to .cljc in my project. I did lein clean but that had no effect. Eventually I renamed the module namespace and that fixed it.
(My guess is that there was some sort of cache of compiled modules and it was referencing a module which no longer existed, but the cljc wasn't re-compiled because a module of that name was still cached.)
When I renamed the module namespace it worked, with no other changes to the code.
We want to automate the production of a Leiningen project tree
entirely from an org-mode babel file. We want to do this so that we
can also create beautiful, typeset documentation via
org-latex-export-to-pdf. We want no less than full literate
programming in Clojure from org-mode.
The following command:
$ lein new ex1
produces a tree that looks like this:
ex1
ex1/.gitignore
ex1/doc
ex1/doc/intro.md
ex1/project.clj
ex1/README.md
ex1/resources
ex1/src
ex1/src/ex1
ex1/src/ex1/core.clj
ex1/test
ex1/test/ex1
ex1/test/ex1/core_test.clj
We want to do the identical thing just by running
org-babel-tangle, and no more, in our org-mode buffer in
emacs.
A difficulty arises: whereas tangle is happy to produce
files in existing subdirectories like src and test, it seems reluctant to produce the subdirectories if they don't exist. That means we must
create the directory structure by some other means -- unless we can
get tangle to do it for us, and that's the subject of this
StackOverflow question.
There are six files in the directory structure created by Leiningen. I can remove them all and re-create them from my org-file with BEGIN_SRC blocks such as the following
#+BEGIN_SRC clojure :tangle ./ex1/src/ex1/core.clj
(ns ex1.core)
(defn foo
"I don't do a whole lot."
[x]
(println x "Hello, World!"))
#+END_SRC
Notice particularly the name of the subdirectory path
#+BEGIN_SRC clojure :tangle ./ex1/src/ex1/core.clj
All is well if our directory structure already exists. org-mode's tangle will
create or update all six files described above and create new files in any existing directory. We don't know how to
get tangle to produce the directories; it complains that there is no such
directory.
A copy of the desired .org file can be found here if you would like more details.
It is possible use the following header in the begin_src section,
:mkdirp yes
FYI There's now a lein project template for using org based projects:
https://github.com/thi-ng/thing-babel
I'm trying out clojure on my second day and I don't understand almost anything yet. I am working with the Programming Clojure 2nd ed. and I am stuck with libraries.
I have Leiningen and have the REPL running. The book first tells the reader to run a simple
(require 'clojure.java.io)
which works just fine (I get a nil). Then it wants to load a file called introduction.clj by running another simple
(require 'examples.introduction)
where I get an error message
FileNotFoundException Could not locate clojure/java/introduction__init.class
or clojure/java/introduction.clj on classpath: clojure.lang.RT.load (RT.java:432)
I downloaded the introduction.clj file and looked where should I place it. The error and the book says the command will search in my classpath, but I have no idea where or what that is (after 1h of searching and reading I still don't get it, sorry). I ran a few commands and I had many classpaths listed (from which none contain a clojure/java/io.clj).
So I tried another approach - find the io.clj file on my disk and simply copy the file there and run it with a command
(require 'clojure.java.introduction)
This doesn't seem to work either. By the way, the io.clj file I found was in "C:\Program Files\clojure\src\clj\clojure\java". I tried running several other .clj files from the java folder as well from the clojure folder, like javadoc.clj or inspector.clj and all seem to work just fine with the above mentioned command. Only the new file doesn't seem to load this way.
Any help appreciated :)
Clojure runs on the Java Virtual Machine, so you will need to learn a bit about PATH and CLASSPATH concepts:
See: http://docs.oracle.com/javase/tutorial/essential/environment/paths.html
Regarding the error message, the Clojure runtime is expecting to find introduction.clj in the directory clojure\java\example\introduction.clj (not where it really should be - see below).
The convention for Clojure namespaces is that the last component is the file name, while any previous components are parent directories. So
clojure.java.introduction
would have to be in the directory (relative to your source "root" or classpath)
clojure\java\introduction.clj
(The lein REPL automatically adds your source root to the classpath).
Another concept you need to understand is where the "root" of your source code is located. For Leiningen (the build tool you are using) the default is either "src" or "src/main/clojure" - as documented in the Leiningen sample project file on GitHub).
Finally, if you get really stuck, it seems the complete project for the book is available on GitHub.
Looking at the project, I see that you should actually be placing the file under src\examples\introduction.clj
Are you reading the book "Programming Clojure"?
I have encountered the same problem. It ban be sovled as follows:
If you start clojure by java:
I work in windows, the clojure.jar is placed in D:\backup\clojure-1.5.1, and the source code of the book "Programming Clojure" is placed in D:\study\clojure\shcloj-code\code. You should first delete the user.clj file in folder D:\study\clojure\shcloj-code\code.
java -cp d:\backup\clojure-1.5.1\clojure-1.5.1.jar;d:\study\clojure\shcloj-code\code clojure.main -r
If you work in linux, replace the ";" with ":"
If you start clojure by lein
You should first cd to the D:\study\clojure\shcloj-code\code folder, and then
lein repl
You should also delete the user.clj file in folder D:\study\clojure\shcloj-code\code.
I'm trying to set up a simple clojure project, and I'm not sure how to load files between the project. I'm sure that the answer is in the documentation, but I can't find a simple answer any where and I'm not sure where to look.
Essentially, my directory looks like this:
Clojure/
clojure/
clojure.jar
other clojure files
clojure-contrib/
clojure-contrib.jar
other contrib files
project/
main.clj
utils.clj
And I want main.clj to be something like this:
(ns project.main
(:require project.utils))
(greet)
and utils.clj to be something like this:
(ns project.utils)
(defn greet [] (println "Hello, World!"))
But that fails with:
Exception in thread "main" java.io.FileNotFoundException: Could not locate project/utils__init.class or project/utils.clj on classpath: (main.clj:1)
When I attempt to run it. My classpath includes the top Clojure/ directory and both jars. I also tried putting the project/ directory in the classpath as well, with no luck.
How do you set up a simple clojure project?
You don't mention what your environment is (i.e. Emacs/SLIME/Swank, vim/Vimclojure), so I'm going to assume you are trying to invoke it from the command line.
You need to have your Clojure/ project directory in the classpath:
java -cp path/to/clojure.jar:path/to/clojure-contrib.jar:path/to/Clojure ...
Make sure to check that paths are correct relative to current working directory. It needs to point to the root of your namespace (i.e. if running in Clojure/, the path is .).
In fact, your project layout Works On My Machine(tm), with the exception that I have use instead of require (but you should've got a different error anyway if you got to the point when Clojure could find all your files).
This answer I posted to another question should hopefully give you an idea of how your filenames should relate to namespace names for things to work. However, since your question is "how to set up a simple Clojure project", the following is a better start:
Go to GitHub and grab Leiningen.
Follow the instructions in the README. You'll end up doing something like
$ lein new my-project
$ cd my-project
# ... edit project.clj ...
$ lein deps
Hack away! You'll need to put your files in the correct places. That will mean putting your source files in the directory tree rooted at my-project/src, with your core namespace most likely residing at my-project/src/my_project/core.clj. But really, I've explained all the details in the answer linked to above, so please read it (and do leave a comment if I missed something). :-)
Leiningen will take care of the basic project layout and setting up the classpath for a REPL / swank / nailgun for you (if you haven't yet come across the latter two, you will soon -- but that's a separate topic, the swank part of which I have covered to a certain degree e.g. in this SO answer), so hopefully you'll never need to deal with the java -cp ... nonsense by hand. (The swank-related answer I linked to in the last parenthetical remark has details on how to set up swank with the correct classpath from within Emacs.)