MergeSort in scala

I came across another codechef problem which I am attempting to solve in Scala. The problem statement is as follows: Stepford Street was a dead end street. The houses on Stepford Street were bought by wealthy millionaires. They had them extensively altered so that as one progressed along the street, the height of the buildings increas...

Use path of source in a scala script file

I am looking for a way to use the full path of the *.scala file that is executed by scala /path/to/file/file.scala The reason is that within my script I would like to use paths, which are relative to the location where file.scala is saved. So, say I want to call /path/to/file/file_second.scala from inside of file.scala while calling file.

"More than one scala library" in Scala/Android project

I have a libgdx android project in eclipse which I've added scala and AndroidProguardScala natures to. This was working great, but suddenly eclipse has started giving me the warning "More than one Scala library found on the build path". I can still build and install the project on a device, but it exits immediately with NoClassDefFoundErr...

sbt-launch.jar not recognizing scala 2.9.1 already installed

I've just installed the Typesafe Stack and am now trying to install SBT via the instructions on the SBT github page However, the SBT installer does not recognize that Scala is already installed, and tries to download a fresh version: ubuntu@ip-10-120-65-227:~/bin$ sbt Getting Scala 2.9.1 (for sbt)... downloading http://repo1.maven.org/ma...

Distributing Scala over a cluster?

So I've recently started learning Scala and have been using graphs as sort of my project-to-improve-my-Scala, and it's going well - I've since managed to easily parallelize some graph algorithms (that benefit from data parallelization) courtesy of Scala 2.9's amazing support for parallel collections. However, I want to take this one step...

How to use Scala varargs from Java code

There are plenty of articles on calling Java varargs from Scala code, but the only thing I could find the opposite way round was this question: Using scala vararg methods in java , which doesn't have any concrete examples. I'm trying to use scala.Console from some Java code, for the reason that java.io.Console doesn't work in Eclipse, w...

Automatically convert Scala code to Java code

I have an app written in Scala and some of my team members want a Java version of it. It is a demo app to use another API written in Scala, and they want a Java version of the app to be able to use the API from Java. However, the app is somewhat large and I don't want to manually rewerite in Java (and they don't want to learn Scala). Is t...

Mergesort Implementation.. Counting number of inversions in an array

I'm taking an online class on Algorithms and trying to implement a mergesort implementation of finding the number of inversions in a list of numbers. But, I cant figure what Im doing wrong with my implementation as the number of inversions returned is significantly lower than the number I get while doing a brute force approach. Ive placed...

Migrating Java TreeMap code to Scala?

I am migrating my Java code base to pure Scala and I am stuck on this one piece of code . I have an implementation of an IntervalMap i.e. a data structures that let's you efficiently map ranges [from,to] to values where the set delete and get operations are all O(log n) (slightly different from an IntervalTree or a SegmentTree). This...

Text editor for scala

I'm tired of using IDEs for scala because it can take several minutes to write one line of code on my computer (before I started programming in scala I didn't surmise that it is slow). It's a great pity that there is no option to turn off some features of scala plugin (of any IDE) that devour 100% of my cpu power and not necessary for me.

PlayFramework2 Passing List to main.scala

Am using Play2.1 for one of my projects. Am trying to create a dynamic menu in the main.scala.html so that it is extendible in all sub-pages. but how should I pass a List to main.scala.html .. I tried on a subpage like this @(menu: List[Rights]) ... @for((l, index) <- menu.zipWithIndex){ @l.rightName .. That was working I can see the...

"object scala not found" trying to run vanilla Play 2 app

I am tearing my hair out trying to get a vanilla Play app running on my Windows (but not for much longer, hopefully!) dev machine. I downloaded the typesafe-stack 2.1 and created a basic Play application using the recommended giterate template: g8 typesafehub/play-scala I then ran sbt run and wait for the server to start, navigate to loc...

Scala - 2.10.2

Scala fuses object-oriented and functional programming in a statically typed programming language.

Why won't the VisualVM Profiler profile my Scala console application?

I assume the question is strongly related to one but it is closed and the solution is not clear for me. I am trying to use VisualVM to profile a console Scala application of mine. I do it by starting VisualVM, starting my Scala application, opening its node in VisualVM, going to the "Profiler" tab and clicking "CPU". The button goes grey...

Tail-recursive bounded stream of pairs of integers (Scala)?

I'm very new to Scala, so forgive my ignorance! I'm trying to iterate of pairs of integers that are bounded by a maximum. For example, if the maximum is 5, then the iteration should return: (0, 0), (0, 1), ..., (0, 5), (1, 0), ..., (5, 5) I've chosen to try and tail-recursively return this as a Stream: @tailrec def _pairs(i: Int, j: Int...

Scala regex pattern match is working properly or not?

I'm new to Scala but I was told that "You are checking if "Toronto Raptor" == matchNY." for the following code snippet @ https://issues.scala-lang.org/browse/SI- 7210 , and I really don't have any idea why "Totonto Raptor" is the only string chosen in the for loop to be matched with the regular expression, can someone explain this to me p...

Using continuation / CPS to implement tail-recursive MergeSort in OCaml

I am trying to implement a tail-recursive MergeSort in OCaml Since Mergesort naturally is not tail-recursive, so I am using CPS to implement it. Also my implementation is inspired by Tail-recursive merge sort in OCaml Below is my code let merge compare_fun l1 l2 = let rec mg l1 l2 acc = match l1, l2 with | ([], []) -> List.rev acc...

Hierarchical navigation w/ Scala in the Play! framework

I need to implement a hierarchy of categories (basically a tree structure). As I am new to Scala, I suspect there is a very good functional approach to this problem. I have used nested sets in PHP/mysql before. Is there an easy way to create a tree structure that enables me to easily retrieve parent and child nodes from the tree, starting...

ZeroMQ Callbacks for Java/Scala

I'm looking for any wrapper for ZeroMQ for Java/Scala. I want to add callbacks to sockets, but by default zmq doesn't provide this feature. Only blocking operation 'recv'. Another way is to create loop and user Poller, but maybe exists some other solutions?...

Good example of implicit parameter in Scala?

So far implicit parameters in Scala do not look good for me -- it is too close to global variables, however since Scala seems like rather strict language I start doubting in my own opinion :-). Question: could you show a real-life (or close) good example when implicit parameters really work. IOW: something more serious than showPrompt ,...

Scala is a string parseable as a double

Suppose that I have a string in scala and I want to try to parse a double out of it. I know that I can just call toDouble and then catch the java num format exception if this fails, but is there a cleaner way to do this? For example if there was a parseDouble function that returned Option[Double] this would qualify. I don't want to put...

scala hibernate/jpa - ignore autogenerated bitmap$init$0 mapping

Trying to use hibernate/jpa with scala. Running into interesting issue. This is my entity definition. @Entity class Product(n: String, d: Double) extends EntityBase { def this() = this("", 0) def this(n: String) = this(n, 0) var name: String = n var price: Double = d @ManyToOne @JoinColumn(name="orderId") var order: Order = _ over...

Java or scala Library to parse latex or MathML string

I need to store a lot of equation and mathematical formula into database for my simulation experimentations, and i think it's better to use some mathML or latex string... but ... I make some googling request, and i'm very surprised because i don't find any eval library in java or scala to transform string latex or string mathML expression...

Why can I not use :: after a list to append a string to it in Scala?

So I assume my issue has to do with what is going on under the hood, but I don't understand why this doesn't works: scala> b = b :: "apple"; <console>:8: error: value :: is not a member of java.lang.String but this does: scala> b = "apple" :: b; b: List[java.lang.String] = List(apple, pear) Thanks.

Scala/Akka Socket Server IterateeRef syntax

Can somebody please explain to me the meaning of this line of code? val state = IO.IterateeRef.Map.async[IO.Handle]()(co ntext.dispatcher) (from http://doc.akka.io/docs/akka/2.0/scala/i o.html I guess this is a partial application of the async function, which is a curried function? But I thought that async was defined in IO.IterateeRef, no...

Scala map with partial function as value

Twitter's Scala school collections section , they show a Map with a partial function as a value: // timesTwo() was defined earlier. def timesTwo(i: Int): Int = i * 2 Map("timesTwo" -> timesTwo(_)) If I try to compile this with Scala 2.9.1 and I get the following: [error] ... missing parameter type for expanded function ((x$1) => "t...

Reduce slug size for Heroku with Play! 2.0 & Scala

I have a specific problem but the solutions are hopefully probably generic for similar problems. I have a Play! framework 2.0 project, using Scala. I am trying to deploy a new version to Heroku However for this project the deployment fails as the slug size is too big (101MB). this app is very simple , so it is most likely a configuratio...

Scala unused import statement with play framework in IntelliJ

I'm trying to learn scala and play framework. I choosed IntelliJ Idea as ide. The problem is editor gives warning on imports like ; "unused import statements" import play.api._ import play.api.mvc._ Also give warnings on declerations like ; "Cannot resolve symbol Controller" object Login extends Controller How can i remove warnings? Steps...

Eclipsify Scala Play project on OSX 10.7

I am getting the following output form command line when I try to eclipsify the Scala sample form app. Williams-MacBook-Pro:forms wfbarksdale$ pwd /Applications/play-2.0-RC4/samples/scala /forms Williams-MacBook-Pro:forms wfbarksdale$ play eclipsify forms [info] Loading project definition from /Applications/play-2.0-RC4/samples/scala /f...

Scala SBT: How to "re-run with -deprecation"

When I compile Scala code, by running sbt compile says: $ sbt compile [warn] there were 5 deprecation warnings; re-run with -deprecation for details How do I do that? (From within SBT?)...

Scala: Best way to parse command-line parameters (CLI)?

What's the best way to parse command-line parameters in Scala? I personally prefer something lightweight that does not require external jar. Related: Java library for parsing command-line parameters? What parameter parser libraries are there for C++? Best way to parse command line arguments in C#...

closing over the loop variable in scala

As discussed in this post by Eric Lippert closing over the loop variable in c# can have unexpected consequences. I was trying to understand if the same "gotcha" applied to scala. First of all, since this is a scala question, I'll try explaining Eric Lippert's C# example adding a few comments to his code // create a list of integers var va...

IntelliJ IDEA scala type info

The Eclipse scala plugin has a very nice info. One can hover over pretty much anything be it a function definition, val, var, function call etc and get type info. This is immensely useful to me to ensure type compatibility especially when I am trying new things out. Is there a similar feature in IntelliJ Idea 12.1 (the latest version as o...

Where to put wrapper scripts in Buildr?

I'm developing a set of command line tools in Scala, using Apache Buildr as my build system. I'd like to include a wrapper script for each tool. Something like this: #!/bin/sh scala myclass $@ These scripts should be installed alongside my jar when I type buildr install . Is there a special directory Buildr recognizes for wrapper scripts...

ScalaQuery many to many

Do anybody have an Idea of how to archive many to many in Scala Query? I want to connect a blog post to a series of tags. This is my database design: I have succeeded with my custom code but when inspecting Scala Querys generated SQL I'm not happy with my solution. I played with a functional approach and it generated many SQL queries resu...

Liquid markup in Java/Scala

I'm looking analogs for Rails Liquid markup ! in Java or Scala languages. Which markup exists like liquid?...

Executing custom function on MongoDB using Casbah/Scala

I've defined a function in MongoDB using its command line client. function something(){...} I was wondering how can I execute a custom MongoDB function using casbah from Scala. Any recommendations ? Thanks,...

Using play framework and scala how to display image path from database

How to display image on view page in play framework and scala application, from image path from database?.. I know how to display image from file on statically , but i have no- idea about how to do this please anyone have knew the answer please share here.. i know my language was poor and pardon for that... with regards... Prasanth AR...

Higher-kinded types-why possible Scala but not F#?

I had always heard that the CLR has a better generics implementation than the JVM which supposedly doesn't have generics at all but is rather some kind of Java compiler trick. So if the CLR has the better generics implementation, why are higher-kinded types not possible in F# but possible in Scala? Does the CLR generics implementation som...

Сортировка слиянием - С++ для начинающих

Привет всем, пытаюсь сделать сортировку 100 чисел слиянием. Выдается ошибка на функции delete :error type ‘int’ argument given to ‘delete’ expected pointer Вот код: Код: #include <iostream> #include <time.h> #include <stdlib.h> #include <iomanip> using namespace std; int intarray[100]; template<class T&...