I have no trouble calling functions in lein repl from my namespaces when I have created a lein new app .... But I don't seem to be able to call functions in lein repl when I just create a library project via lein new .... Details follow:
When I create a lein app with, say lein new app my-app, and then, from the project directory (the directory that contains project.clj), I do lein repl. The repl leaves me in the namespace my-app.core
my-app.core=>
I can now call functions in the repl, even functions defined in side files.
my-app.core=> (-main)
; Hello, world!
my-app.core=> (my-app.anotherfile/foo)
; Hey, there; this is foo from anotherfile
so long as I :require [my-app.anotherfile] in the ns macro of core.clj.
Ok, great; now I would like to do similarly with a lein library. So I lein new my-lib, then lein repl, and I'm in the user namespace:
user=>
huh? Ok, well, my lib contains a function that I want to call (this is just the one that leiningen creates by default)
(ns my-lib.core)
(defn foo
"I don't do a whole lot."
[x]
(println x "Hello, World!"))
I try
user=> (in-ns 'my-lib.core)
my-lib.core=> (foo 42)
; CompilerException java.lang.RuntimeException: Unable to resolve symbol: foo in this context, compiling:(NO_SOURCE_PATH:1:1)
nope. How about this?
user=> (my-lib.core/foo 42)
; ClassNotFoundException two-files-lib.core java.net.URLClassLoader$1.run (URLClassLoader.java:202
aha! Different error, but still no cure in sight. lein compile and lein javac don't seem to do anything either.
I have been unable to find or deduce the correct incantations in the docs or online and would be grateful for advice.
In a default lein new project you need to require the namespaces you wish to use explicitly -- (require 'my-lib.core). in-ns simply creates a new empty namespace of the given name if it doesn't already exist, it doesn't load any code from the classpath.
App projects do this automatically and switch to the main namespace in the REPL task, because they have a :main foo.core entry in their project.clj by default. It's possible to do it for a library, but you shouldn't -- as a side effect, it causes AOT compilation of the main namespace, which is generally undesirable.
Instead, in lein2 you can use :repl-options {:init-ns my-lib.core}.
Related
I have implemented a hyphenation algorithm (at namespace hyphenator-clj.core), defined it as org.clojars.nikonyrh.hyphenator-clj 0.1.0 at defproject and pushed it to Clojars. Uberjar seems to have files like core__init.class, core.clj and core.class.
However when I try to use it as a dependency on an other project I get this error:
$ lein uberjar
Retrieving org/clojars/nikonyrh/hyphenator-clj/org.clojars.nikonyrh.hyphenator-clj/0.1.0/org.clojars.nikonyrh.hyphenator-clj-0.1.0.pom from clojars
Retrieving org/clojars/nikonyrh/hyphenator-clj/org.clojars.nikonyrh.hyphenator-clj/0.1.0/org.clojars.nikonyrh.hyphenator-clj-0.1.0.jar from clojars
Compiling example.core
java.io.FileNotFoundException: Could not locate org/clojars/nikonyrh/hyphenator_clj__init.class or org/clojars/nikonyrh/hyphenator_clj.clj on classpath. Please check that namespaces with dashes use underscores in the Clojure file name., compiling:(core.clj:1:1)
Exception in thread "main" java.io.FileNotFoundException: Could not locate org/clojars/nikonyrh/hyphenator_clj__init.class or org/clojars/nikonyrh/hyphenator_clj.clj on classpath. Please check that namespaces with dashes use underscores in the Clojure file name., compiling:(core.clj:1:1)
at clojure.lang.Compiler$InvokeExpr.eval(Compiler.java:3657)
at clojure.lang.Compiler.compile1(Compiler.java:7474)
at clojure.lang.Compiler.compile1(Compiler.java:7464)
at clojure.lang.Compiler.compile(Compiler.java:7541)
at clojure.lang.RT.compile(RT.java:406)
at clojure.lang.RT.load(RT.java:451)
at clojure.lang.RT.load(RT.java:419)
at clojure.core$load$fn__5677.invoke(core.clj:5893)
...
Must I change my project's folder structure so that it matches the expected org/clojars/nikonyrh/hyphenator_clj__init.class, or can I somehow override the current behavior? If there is a good tutorial about this out there I would be happy to read it.
Basically I would like to get this example project to work. project.clj:
(defproject example "0.0.1-SNAPSHOT"
:description ""
:dependencies [[org.clojure/clojure "1.8.0"]
[org.clojars.nikonyrh.hyphenator-clj "0.1.0"]]
:javac-options ["-target" "1.6" "-source" "1.6" "-Xlint:-options"]
:aot [example.core]
:main example.core)
src/example/core.clj:
(ns example.core
(:require [org.clojars.nikonyrh.hyphenator-clj :as h])
(:gen-class))
(defn -main [& argv] (doseq [arg argv] (println (h/hyphenate arg :hyphen \-))))
I'm suspecting I also have the english.txt in a wrong directory, as it isn't contained in the uberjar but resource files are an other topic.
You would probably be better off not using a hyphen in the namespace hyphenator-clj. Why not just use hyphenator? But if you do I suspect that the name of the directory should have an underscore in it rather than a hyphen, so be: hyphenator_clj.
If fixing that issue doesn't help then another thing to look out for, which I can't see from your question, is where exactly is core.clj in the directory structure, and does the project.clj reflect that? For instance is the path for the namespace hyphenator-clj.core in a src directory off the root of your project? The root of your project being defined as where the project.clj is located.
Something else that would be good to see in the question is whether you can get the program to work just locally, without having packed it up into an uberjar and shipped it to clojars. My guess would be that it does work locally, but it would help for that to be stated.
Okay taking a look at your links now. You might like to read a working project deployed to clojars, that has hypens in its name, for instance here. The first difference you might notice is the project name you use is rather long: org.clojars.nikonyrh.hyphenator-clj. It should just be hyphenator-clj. Also I would recommend having an identifier ending in "-SNAPSHOT" as that project does.
But taking a look at the bigger picture, a great idea you suggested in the comments is to test without Clojars being in the mix at all. To do this use lein install on the library you want to use from another lein project.
Ahaa at least I understand the process a bit better now, basically my require has to match the structure of the used JAR file, which may be very different from the project's name. For example cc.qbits/spandex is actually required as qbits.spandex.
The english.txt dependency was fixed by moving it to resources folder, deploying the new version to Clojars and importing the dependency as it exists in the JAR:
(ns example.core
(:require [hyphenator-clj.core :as h])
(:gen-class))
(defn -main [& argv] (doseq [arg argv] (println (h/hyphenate arg :hyphen \-))))
I'm writing a framework. Hopefully I'd like implementing projects to use the main method for the framework.
In my demo project, in definition.clj I have:
(ns definition
(:gen-class))
(def widget
{:this :that})
(defn -main [& args] (prn "MAIN"))
In my project.clj file I have :main ^:skip-aot definition. When I lein run I get the expected
lein run
"MAIN"
When I lein repl I can see the widget and -main functions:
definition=> definition/-main
#object[definition$_main 0x3ce2a73f "definition$_main#3ce2a73f"]
definition=> definition/widget
{:this :that}
When I call (all-ns) I can see the namespace as #object[clojure.lang.Namespace 0x64965348 "definition"].
Here's the problem: if I change the main method to that defined in another project (which is a dependency):
:main ^:skip-aot the-framework.core
The main method works. But the namespaces are no longer visible:
the-framework.core=> definition/widget
CompilerException java.lang.RuntimeException: No such namespace: definition, compiling:(/private/var/folders/gc/_1drfv2n2m588qnq5xz35g080000gn/T/form-init8820469930602256143.clj:1:1325)
The only thing that changed was the :main value in the Leiningen project.clj definition.
Is there a way to change the main method to an namespace not defined in the project without breaking the namespaces in the project?
In a fresh lein (~2.5) repl, I type:
(require '[clojure.string :as string])
And I can use string as expected. However, when trying to require core.asnc like so, I get an error msg:
(require '[clojure.core.async :as ca])
FileNotFoundException Could not locate clojure/core/async__init.class or clojure/core/async.clj on classpath. clojure.lang.RT.load (RT.java:449)
thanks to your answers I managed now to require arbitrary libs in a repl on runtime using pomegranate or alembic. But what about macros? How - for example - do I get the 'go' macro in the repl? There isn't something like (require-macros ... in analogy to the approach one would take when requiring core.async in a project's ns declaration.
core.async is not part of the clojure.core library. You need to add the core.async jar or sources to your classpath. The easiest way to do this is with a dependency via project.clj, but there are also tools like pomegranate and alembic for doing this at runtime, which could be added to your local profiles.clj.
For the development of a library I started from a lein project, invoked like so:
lein new mylib
if I call lein install now, I can access my library in other projects. But trying to immidiately test the functions I wrote failed:
lein repl
...
(dir mylib.core)
Exception No namespace: mylib.core found clojure.core/the-ns (core.clj:4008)
Do I have to add something to the project.clj file maybe?
In order to use a library you must cause the code to be loaded - that it be on the classpath is not sufficient.
You can do this easily in an ns declaration in a file of course, but in the repl it can be easier to use (require '[my-lib.whatever :as w]) after which one can call (w/foo) (w/bar) etc. as expected. You can also use (in-ns 'my-lib.whatever) in order to switch to the namespace, but this will not give you a good result unless you have previously used require or use or load-file etc. to get the definitions first.
Let's say you created a new library named clj-foo.
% lein new clj-foo
Start your repl.
% cd clj-foo
% lein repl
In the repl, load the main entry point to your library and switch to its namespace.
(load-file "src/clj_foo/core.clj")
(ns clj-foo.core)
Now you're in the clj-foo.core namespace, make sure to add back in the repl ns to get things like doc available.
(use 'clojure.repl)
That's it. You're all set to start calling functions in your library. Note that other library files will be available from the clj-foo.core namespace if they were loaded by namespace declaration at the top of clj_foo/core.clj. If not, then you'll need to invoke load-file with their path as well.
If you make changes in core.clj. You can invoke load-file again to pick up the new code. As you progress, you can use cider to facilitate loading of individual functions and files. But that's for another question. :)
You need to add a dependency to use your library from another project. To do this add a vector (a tuple-2) to the vector that is the value of the :dependencies key in the project.clj file. Here's an example:
:dependencies [[org.clojure/clojure "1.7.0"]
[org.clojure/clojurescript "1.7.170"]
[org.clojure/core.async "0.2.371"]
[default-db-format "0.1.0-SNAPSHOT"]
[com.andrewmcveigh/cljs-time "0.3.14"]]
My own local library is called default-db-format. Its really no different to adding a dependency for com.andrewmcveigh/cljs-time.
As you say you can already do this, but are having trouble getting a REPL connection to the project of the library itself. When you go (in-ns 'some-path), you need the single quote in front of some-path. Note that some-path is a different thing to the name of your library.
Rather than use lein repl you can use the figwheel repl - if your project is setup with figwheel. My library has only one entry point and that is lein figwheel devcards. After that I had no problem going to a namespace and trying out a function:
cljs.user=> (in-ns 'default-db-format.core)
nil
default-db-format.core=> (check 1 2)
As noisesmith mentioned having a REPL in your IDE is the best setup. No fiddly typing just bring up pre-configured REPLs (per namespace) with the click of a button (or keystroke). Figwheel/Cursive setup instructions here.
I was also facing the same issue with the following configuration:
Leiningen 2.9.0 on Java 1.8.0_201 Java HotSpot(TM) 64-Bit Server VM
My file looks like this, and from the repl I desired to invoke the foo function
(ns cljtest.test
(:gen-class))
(defn foo [input]
(assoc {} "a" 123))
Both these approaches worked fine for me on the repl.
1)Switch to the appropriate name space:
cljtest.core=> (in-ns 'cljtest.test)
#object[clojure.lang.Namespace 0x90175dd "cljtest.test"]
cljtest.test=> (foo nil)
{"a" 123}
cljtest.test=>
2)Require the appropriate name space:
cljtest.core=> (require '[cljtest.test :as test])
nil
cljtest.core=> (test/foo nil)
{"a" 123}
cljtest.core=>
I'm a beginner with clojure, only starting it yesterday.
I have gathered that a simple way to create a standalone app is with leiningen lein new foo.
I tried to create a hello world test project with leiningen. I added :main and :aot directives to project.clj, added :gen-class to the core.clj file and tried lein run, but I get errors about class definition not found.
Exception in thread "main" java.lang.NoClassDefFoundError:
Caused by: java.lang.ClassNotFoundException:
at java.net.URLClassLoader$1.run(URLClassLoader.java:217)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
at java.lang.ClassLoader.loadClass(ClassLoader.java:321)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294)
at java.lang.ClassLoader.loadClass(ClassLoader.java:266)
The core.clj file
(ns test.core
(:gen-class))
(defn -main [& args] (println "Hello main"))
And the project.clj file
(defproject test "1.0.0-SNAPSHOT"
:description "FIXME: write description"
:main test.core
:aot [test.core]
:dependencies [[org.clojure/clojure "1.2.1"]])
Edit: After further testing, it seems like copying the project to my desktop works as is, which I think points to that the environment on my laptop is somehow borked, but I don't know how.
The environment on desktop is clojure from repositories and leiningen from AUR. On laptop the clojure is from clojure.org and leining is from github.
[UPDATE April 2013]
Leiningen 2, which has been officially released for some time, includes the concept of project templates. By default, Leiningen provides an app template that provides what you need out of the box. Try:
lein new app my-project
You will see that Leiningen creates the familiar project template, but also includes:
The default namespace of my-project.core as the :main entry in your project.clj file
The :gen-class form in the namespace declaration of my-project.core
A default -main function in the my-project.core namespace
For those who cannot yet use Leiningen 2, the lein-newnew plugin provides an equivalent experience under Leiningen 1.
[/UPDATE]
To build a project that, when run, prints "Hello World!", you'd do as follows (revision of your process above):
Setup
lein new my-project
cd my-project
lein deps
You should now have a basic structure in place and the Clojure jar in your lib folder.
Write a Function
Now edit src/my_project/core.clj with your editor of choice, adding the following below the (ns ...) form:
(defn -main []
(println "Hello World!"))
This function is inside your my-project.core namespace. To ensure this gets run as your main, let's add a gen-class parameter to your namespace definition at the top, so that it now looks like this at the top of core.clj:
(ns my-project.core
(:gen-class :main true))
So all together, your core.clj file looks like this:
(ns my-project.core
(:gen-class :main true))
(defn -main []
(println "Hello World!"))
Configure it as the Main Function
Once you've got src/my_project/core.clj edited as above, you need to tell Leiningen (the build tool) where the "main" function for your project lives. Here's an example defproject form that does this:
(defproject my-project "1.0.0-SNAPSHOT"
:description "My Project"
:dependencies [[org.clojure/clojure "1.2.1"]]
:main my-project.core)
Now the -main function inside my-project.core becomes the entry-point for your program.
Run It
You can now have two options for running this project:
Use lein run at the command-line while at the root of your my-project project
Create a standalone jar file by running lein uberjar. You can then run the resultant jar file by running java -jar my-project-1.0.0-SNAPSHOT-standalone.jar
Figured it out. I had the latest leiningen from git, which was borked somehow. I checked out the 1.6.1 tag and ran self-install, and now it works.
I missed it, You named your project test, you can't do that change the name to something else it will work.
You say above
lein new foo
what you mean is
lein new test