I want to use Jcurses with Scala on a 64-bit Ubuntu.
Unfortunately i didn't find any tutorial about this subject. Can anybody help me!
My test program "testjcurses.scala"
import jcurses.system._
object TestJcurses {
def main(args:Array[String]) {
println("okay")
Toolkit.init()
}
}
I processed it the following way:
fsc -cp ~/software/Java/jcurses/lib/jcurses.jar:~/software/Java/jcurses/src -d . -Djava.library.path=~/software/Java/jcurses/lib testjcurses.scala
scala -cp ~/software/Java/jcurses/lib/jcurses.jar:~/software/Java/jcurses/src:. -Djava.library.path=~/software/Java/jcurses/lib TestJcurses
The result is:
okay
java.lang.NullPointerException
at jcurses.system.Toolkit.getLibraryPath(Toolkit.java:97)
at jcurses.system.Toolkit.<clinit>(Toolkit.java:37)
at TestJcurses$.main(testjcurses.scala:9)
at TestJcurses.main(testjcurses.scala)
..........
Can anybody help me?
Unfortunately you can't use ~ in bash like that — ~ is expanded to your home dir only right after an (unquoted) space (technically, at the beginning of a bash word, but "after a space" is the simple version). Look how your command line is expanded:
$ echo scala -cp ~/software/Java/jcurses/lib/jcurses.jar:~/software/Java/jcurses/src:. -Djava.library.path=~/software/Java/jcurses/lib TestJcurses
scala -cp /Users/pgiarrusso/software/Java/jcurses/lib/jcurses.jar:~/software/Java/jcurses/src:. -Djava.library.path=~/software/Java/jcurses/lib TestJcurses
As you can see, the ~ is there in the expanded version, and will arrive unchanged to your program, which will be unable to interpret it as anything since tilde expansion is a job for the shell.
Also, you shouldn't need the source directory ~/software/Java/jcurses/src in your classpath (since source files aren't needed to run the program). So try:
scala -cp ~/software/Java/jcurses/lib/jcurses.jar:. -Djava.library.path=$HOME/software/Java/jcurses/lib TestJcurses
Related
I have a Scala script that looks something like:
#!/bin/sh
PATH=${SCALA_HOME}:${PATH}
exec scala "$0" "$#"
!#
Console.println("Hello, world!")
Is there some way in Gradle to set the version of Scala to be used, have it implicitly set SCALA_HOME, and execute the script?
There is no built-in feature for this. The way to tackle this is to declare two tasks: A Copy task that downloads the Scala distribution and unpacks it to a local directory, and an Exec task that sets the SCALA_HOME environment variable to the copy task's output directory and executes your script.
Here is an example of executing Scala from Gradle. It is a nascent attempt to build a plugin using Scalafmt. Of note is how nasty it is to use static values.
buildscript {
repositories {
mavenCentral()
}
dependencies {
classpath 'com.geirsson:scalafmt-core_2.11:0.4.2'
}
}
task scalafmt << {
String target = "object FormatMe { List(Split(Space, 0).withPolicy(SingleLineBlock(close)), Split(Newline, 1).withPolicy{ case Decision(t#FormatToken(_, `close`, _), s) => Decision(t, List(Split(Newline, 0)))}.withIndent(2, close, Right)) }"
def config = org.scalafmt.config.ScalafmtConfig$.MODULE$.default
def range = scala.collection.immutable.Set$EmptySet$.MODULE$
println org.scalafmt.Scalafmt.format(target, config, range).formattedCode()
}
I know this is not quite on topic but I couldn't find anywhere else to put this and I hope it is of some value to people who ended up here for the same reason I did.
Gradle has an Exec task in which you can set the environment to be passed to the new process. You could pass SCALA_HOME through that.
I have the following Scala 2.10 script that works fine:
#!/bin/bash
classpath="${CLASSPATH}"
unset CLASSPATH
exec ${SCALA_HOME}/bin/scala -cp "${classpath}" "$0" "$#" 2>&1
!#
import stuff
But when CLASSPATH isn't unset, it fails with stuff like:
$ ./setter-for-catan.scala
./setter-for-catan.scala:12: error: not found: object play
import play.api.libs.json.JsArray
^
one error found
Why is this happening?
The scala script has a modest -debug option.
Use -Ylog-classpath to see what the compiler is using.
Use -nc to say "no compile server daemon".
Use fsc -shutdown to start over.
Package changes are anathema, so unexpected dirs in the path with package names, or old package objects, etc, cause inexplicable build problems.
Use PathResolver to dump what classpath it sees.
An empty directory with your package name can interfere with package discovery.
${SCALA_HOME}/bin/scala -cp "${classpath}" scala.tools.util.PathResolver
${SCALA_HOME}/bin/scala -cp "${classpath}" scala.tools.util.PathResolver some-args
You'll see something like:
apm#mara:~/tmp/scripts$ ./foo.sh
object Environment {
scalaHome = /media/Software/scala-2.10.1 (useJavaClassPath = true)
javaBootClassPath = <1122 chars>
javaExtDirs =
/usr/lib/jvm/java-7-openjdk-amd64/jre/lib/ext
/usr/java/packages/lib/ext
javaUserClassPath = ""
scalaExtDirs =
}
object Defaults {
scalaHome = /media/Software/scala-2.10.1
javaBootClassPath =
/usr/lib/jvm/java-7-openjdk-amd64/jre/lib/resources.jar
/usr/lib/jvm/java-7-openjdk-amd64/jre/lib/rt.jar
/usr/lib/jvm/java-7-openjdk-amd64/jre/lib/sunrsasign.jar
/usr/lib/jvm/java-7-openjdk-amd64/jre/lib/jsse.jar
/usr/lib/jvm/java-7-openjdk-amd64/jre/lib/jce.jar
/usr/lib/jvm/java-7-openjdk-amd64/jre/lib/charsets.jar
/usr/lib/jvm/java-7-openjdk-amd64/jre/lib/netx.jar
/usr/lib/jvm/java-7-openjdk-amd64/jre/lib/plugin.jar
/usr/lib/jvm/java-7-openjdk-amd64/jre/lib/rhino.jar
/usr/lib/jvm/java-7-openjdk-amd64/jre/lib/jfr.jar
/usr/lib/jvm/java-7-openjdk-amd64/jre/classes
/media/Software/scala-2.10.1/lib/akka-actors.jar
/media/Software/scala-2.10.1/lib/jline.jar
/media/Software/scala-2.10.1/lib/scala-actors.jar
/media/Software/scala-2.10.1/lib/scala-actors-migration.jar
/media/Software/scala-2.10.1/lib/scala-compiler.jar
/media/Software/scala-2.10.1/lib/scala-library.jar
/media/Software/scala-2.10.1/lib/scala-partest.jar
/media/Software/scala-2.10.1/lib/scalap.jar
/media/Software/scala-2.10.1/lib/scala-reflect.jar
/media/Software/scala-2.10.1/lib/scala-swing.jar
/media/Software/scala-2.10.1/lib/typesafe-config.jar
scalaLibDirFound = Some(/media/Software/scala-2.10.1/lib)
scalaLibFound = /media/Software/scala-2.10.1/lib/scala-library.jar
scalaBootClassPath =
scalaPluginPath = /media/Software/scala-2.10.1/misc/scala-devel/plugins
}
COMMAND: 'scala some-args'
RESIDUAL: 'scala some-args'
There may be some funky state leftover from the compiler daemon. Try fsc -shutdown or scala -nc to reset the daemon.
I have the Akka microkernel below:
class ServiceKernel extends Bootable {
val system = ActorSystem("service-kernel")
def startup = {
system.actorOf(Props(new Boot(false))) ! Start
}
def shutdown = {
system.shutdown()
}
}
Because the kernel extends Bootable and not App, how would I access command line arguments used when starting the kernel? For instance if I run the kernel using start namespace.ServiceKernel -d rundevmode or similar. Thanks!
Additional Info
I thought it would be worth adding this information about the start up script in the microkernel. In /bin/start you notice the following:
#!/bin/sh
AKKA_HOME="$(cd "$(cd "$(dirname "$0")"; pwd -P)"/..; pwd)"
AKKA_CLASSPATH="$AKKA_HOME/config:$AKKA_HOME/lib/*"
JAVA_OPTS="-Xms256M -Xmx512M -XX:+UseConcMarkSweepGC -XX:+CMSClassUnloadingEnabled -XX:ParallelGCThreads=2"
java $JAVA_OPTS -cp "$AKKA_CLASSPATH" -Dakka.home="$AKKA_HOME" akka.kernel.Main "$#"
Although om-nom-nom originally suggested -D options, it looks like it's in use and the main start up parameter is being passed to the akka.kernel.Main class (which in this case would be the ServiceKernel class above).
Here is the minimal example:
object Foo extends App {
val debugModeOn = System.getProperty("debugmode") != null
val msg = if (debugModeOn) "in debug mode" else "not in debug mode"
println(msg)
}
» scala Foo -Ddebugmode
in debug mode
» scala Foo
not in debug mode
You can do extra check to overcome this issue:
» scala Foo -Ddebugmode=false
in debug mode
P.S. you might also want to use Properties helper, that contains bunch of methods like propOrNone, propOrElse, etc
It looks like in the sh script that they give you an opportunity to provide JAVA_OPTS, and if not, they give you one that they pre-define. I suppose you could just set JAVA_OPTS in a script that then calls this one, specifying a -D option for your custom args in the JAVA_OPTS. That way you can be sure your custom args get passed in via the -D system property you specify. Hackish but I think it should work. The beauty of -D is that you can supply as many as you want, so the fact that they are already using it for some of their own system properties should not matter.
This question may sound a bit stupid, but I couldn't figure out, how to start a Scala method from the command line.
I compiled the following file Test.scala :
package example
object Test {
def print() {
println("Hello World")
}
}
with scalac Test.scala.
Then, I can run the method print with scala in two steps:
C:\Users\John\Scala\Examples>scala
Welcome to Scala version 2.9.2 (Java HotSpot(TM) Client VM, Java 1.6.0_32).
Type in expressions to have them evaluated.
Type :help for more information.
scala> example.Test.print
Hello World
But what I really like to do is, to run the method directly from the command line with one command like scala example.Test.print.
How can I achieve this goal ?
UPDATE:
Suggested solution by ArikG does not work for me - What I am missing ?
C:\Users\John\Scala\Examples>scala -e 'example.Test.print'
C:\Users\John\AppData\Local\Temp\scalacmd1874056752498579477.scala:1: error: u
nclosed character literal
'example.Test.print'
^
one error found
C:\Users\John\Scala\Examples>scala -e "example.Test.print"
C:\Users\John\AppData\Local\Temp\scalacmd1889443681948722298.scala:1: error: o
bject Test in package example cannot be accessed in package example
example.Test.print
^
one error found
where
C:\Users\John\Scala\Examples>dir example
Volume in drive C has no label.
Volume Serial Number is 4C49-8C7F
Directory of C:\Users\John\Scala\Examples\example
14.08.2012 12:14 <DIR> .
14.08.2012 12:14 <DIR> ..
14.08.2012 12:14 493 Test$.class
14.08.2012 12:14 530 Test.class
2 File(s) 1.023 bytes
2 Dir(s) 107.935.760.384 bytes free
UPDATE 2 - Possible SOLUTIONs:
As ArikG correctly suggested, with scala -e "import example.Test._; print" works well with Windows 7.
See answer of Daniel to get it work without the import statement
Let me expand on this solution a bit:
scala -e 'example.Test.print'
Instead, try:
scala -cp path-to-the-target-directory -e 'example.Test.print'
Where the target directory is the directory where scala used as destination for whatever it compiled. In your example, it is not C:\Users\John\Scala\Examples\example, but C:\Users\John\Scala\Examples. The directory example is where Scala will look for classes belonging to the package example.
This is why things did not work: it expected to find the package example under a directory example, but there were no such directory under the current directory in which you ran scala, and the classfiles that were present on the current directory were expected to be on the default package.
The best way to do this is to extend App which is a slightly special class (or at least DelayedInit which underlies it is):
package example
object Test extends App {
println("Hello World")
}
It's still possible to add methods to this as well, the body of the object is executed on startup.
Here you go:
scala -e 'example.Test.print'
I simply could not get it to work not matter what. The only thing it does is that it lists the help. that's all. Any help, example is appreciated. Thanks much.
I installed the Debian package (then the prerequisite package daemon to get it to finish installing), then got the jarfile from the warfile according to instructions, and it works for me:
jcomeau#intrepid:~$ java -jar /usr/local/bin/hudson-cli.jar -s http://localhost:8080/ version
2.0.1
jcomeau#intrepid:~$ java -jar /usr/local/bin/hudson-cli.jar -s http://localhost:8080/ list-changes
Argument "JOB" is required
java -jar hudson-cli.jar list-changes args...
Dumps the changelog for the specified build(s)
JOB : Name of the job to build
RANGE : Range of the build records to delete. 'N-M',
'N,M', or 'N'
-format [XML | CSV | PLAIN] : Controls how the output from this command is
printed.