I have followed the readme from the lein new re-frame <project-name>template exactly, but I get the error:
No :main namespace specified in project.clj.
I know this is a well documented error, but when I add the line :main my-first-reframe-app.core to my project.clj and a -main function to core.cljs namespace, the compiler throws a huge error when I use lein dev.
Why won't this template run out of the box for me and how should I fix the problem? Thanks.
/edit Nowadadays, as can be seen in the README of the downloaded template
Use:
lein watch
and navigate to http://localhost:8280/ to see the started shadow-cljs app in development mode.
Related
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
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, i.e. 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, e.g. with
(defproject blabber "0.1.0-SNAPSHOT"
:dependencies [[org.clojure/clojure "1.8.0"]
[net.mikera/core.matrix "0.50.0"]]).
Let's say I find a cool clojure library like https://github.com/clojurewerkz/buffy
Now I want to use it. And it only lives on github.
How do I do this? I would love a full start to finish hello world example.
I've read about compiling it as a jar and using that, or using :dependencies in my project.clj but so far no examples have been complete, and I'm new.
For example in python I'd git clone the repo into the root of my working tree and any file could just say import buffy
I just learned this five minutes ago. I wanted to use the clojure-csv library, here's what I did using Leiningen
Make a new leiningen project
lein new app csvtest
Now I have a folder called csvtest/. In the csvtest/project.clj file, edit the dependencies section to add the clojure-csv github path and a version. I'm not quite sure how the versioning works to be honest:
:dependencies [[org.clojure/clojure "1.5.1"]
[clojure-csv/clojure-csv "2.0.1"]]
Now run lein deps to automagically download any unresolved dependencies for your project
$ lein deps
...
Retrieving clojure-csv/clojure-csv/2.0.1/clojure-csv-2.0.1.pom from clojars
...
Now edit csvtest/src/csvtest/core.clj. Make it look like this:
Edit: (Based on sveri's comment I changed :use closjure-csv.core to the :require line)
(ns csvtest.core
(:gen-class)
(:require [clojure-csv.core :refer [parse-csv]]))
(defn -main
"I don't do a whole lot ... yet."
[& args]
(println (parse-csv "1,2,3,hello,world")))
You have to add the (:require [clojure-csv.core :refer [parse-csv]]) line to your ns, and in main it calls parse-csv, one of the functions provided by the library. From reading, it looks like :use is depreciated in favor of :require.
Note: For anyone coming from python (like me), it looks like doing :use clojure-csv.core is akin to from closure_csv import *, which is bad practice in python as well. And (:require [clojure-csv.core :refer [parse-csv]]) is like from clojure_csv import parse_csv
Run the project with lein run. My output was
$ lein run
([1 2 3 hello world])
I hope that helps!
You can download/use it from Clojars.
Clojars link:
https://clojars.org/clojurewerkz/buffy
To use it with Leiningen, add this to your dependencies(on project.clj file):
[clojurewerkz/buffy "1.0.0-beta4"]
After that, you can run lein deps from your project root folder in order to download dependencies.
To use dependencies directly from Github repos, you can check out this: https://github.com/tobyhede/lein-git-deps
Using lein (which is Clojure's build tool) you have a project.clj file. if you do lein new project-name you get a new project named "project-name", with a project.clj file in it. look at that file, you will see a :dependencies entry in it as in this example:
:dependencies [[org.clojure/clojure "1.5.1"]]
all you must do to include buffy, is look at their github site, and find out which version to use, then you add it to the :dependecies list:
:dependencies [[org.clojure/clojure "1.5.1"]
[clojurewerkz/buffy "1.0.0-beta3"]]
now you can simply do lein deps which will download the dependencies and once you written your code lein run to actually run it.
read a little about lein and check out its sample project.clj file to get a better understanding of how you should use clojure.
I'm not at all familiar with clojure, and I have the source for a project that I'm trying to build. The project has a project.clj file, which google says means I should use the lein build tool. However:
$ lein compile #lein jar does the same thing
Exception in thread "main" java.lang.RuntimeException: java.io.FileNotFoundException: Could not locate testui/core__init.class oCompiling testui.core
r testui/core.clj on classpath
I suspect that project.clj may be broken. core.clj is located in src/com/foodient/semanticanalysis/testui, and project.clj looks like this:
(defproject testui "1.0.0-SNAPSHOT"
:description "FIXME: write description"
:dependencies [[org.clojure/clojure "1.3.0"]
[org.apache.poi/poi "3.8-beta4"]
[gate-clj "1.0.0"]]
:aot [testui.core]
:main testui.core
:run-aliases {:test testui.core/-main})
Any ideas?
If you set up a lein project and the name has that Clojuristic dash in it, like bene-csv (one of mine), then lein new bene-csv creates several directories and ./bene-csv/project.clj. My core.clj is located in ./bene-csv/src/bene_csv/core.clj. Note the dash is dropped in bene_csv in favor of an underscore.
As to your problem more than likely core.clj is not located where lein expects it, which should be ./testui/src/testui/core.clj. I hope this helps.
I think the issue is that the core.clj is not in the right directory. It should be in the src/testui directory.
My guess is that you should change references to your code from
testui.core
to
com.foodient.semanticanalysis.testui.core
The reason for it is that the part of a namespace before the last dot corresponds to a package name (this term comes from java and jvm)
You indicated that your sources are in:
src/com/foodient/semanticanalysis/testui
so the package name is com.foodient.semanticanalysis.testui
You should probably also update the namespace declaration in your clojure source files to match this convention (or move your source to src/testui).
Hope it helps.
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
I have a leiningen project that uses clojure 1.2.1. I would like to add a dependency to a package that requires clojure 1.3.0-beta1. So I decided to upgrade my project to the newer version.
To be honest I was not sure what that involved but I did the following..
In my project.clj I changed my dependency from
[org.clojure/clojure "1.2.1] to [org.clojure/clojure "1.3.0"]
I use swank so I changed my swank clojure dependency to [swank-clojure "1.3.2"].
I then ran
lein deps
Lastly I manually edited my /usr/bin/lein file to change the CLOJURE_JAR variable to point to the newer clojure jar.
When I start swank with 'lein swank'. It starts fine and I now get the following warning messages
like so..
Warning: default-javac-options not declared dynamic and thus is not dynamically rebindable, >but its name suggests otherwise. Please either indicate ^:dynamic default-javac-options or >change the name.
Which I think has to do with clojure 1.3.0.
I then fire up Aquamacs and run slime-connect. The REPL starts fine but when call clojure-version
if get "1.2.1".
; SLIME 20100404
user> (clojure-version)
"1.2.1"
Is there something else I need to do?
I think, that you need to add :exclusions list to swank-clojure specification, something like:
:dev-dependencies [[swank-clojure "1.3.2"
:exclusions [org.clojure/clojure]]]
although, I just checked my installation, and clojure 1.3 worked out of box. I think, that you just forgot to call lein clean before lein deps...