You can do a source dependency on your project like that : 


     lazy val core = RootProject(file(&quot;../CoreLibrary&quot;))

     val main = Project(id = &quot;application&quot;, base = file(&quot;.&quot;)).dependsOn(core) 


I have a working example with a multimodule play build : https://github.com/ahoy-jon/play2MultiModule/blob/master/playapp/project/Build.scala

But I think the proper way (it depends of your context) of doing it is to create a 

     -&gt; /project/
       -&gt; Build.scala
     -&gt; /ApplicationA
       -&gt; /project
         -&gt; /build.sbt
     -&gt; /CoreLibrary
       -&gt; /project
         -&gt; /build.sbt


referencing the two projects and the dependencies between them.

With sbt 0.12.1 it seems possible to get a simple reference to a project :

I used `ProjectRef` instead of `RootProject`

http://www.scala-sbt.org/0.12.1/api/sbt/ProjectRef.html

    ProjectRef(file(&quot;../util-library&quot;), &quot;util-library&quot;)

sbt-eclipse also works.

Since **sbt 0.13**, you may create multi-project definitions directly in `.sbt` without needing a `Build.scala` file.

So adding the following to  **ApplicationA/project/build.sbt** would be sufficient.

    lazy val core = RootProject(file(&quot;../CoreLibrary&quot;))
    
    val main = Project(id = &quot;application&quot;, base = file(&quot;.&quot;)).dependsOn(core) 




I can&#39;t figure out the syntax to do inline collection initialization for:

    var a = new List&lt;KeyValuePair&lt;string, string&gt;&gt;();


How do you use object initializers for a list of key value pairs?

Is there a way to ensure all values in an `IN` clause are matched?

Example:

I can use IN as: `IN (5,6,7,8)`.

I need it to work like an `AND` across multiple rows.

**UPDATE:**
I need this to list companies from db that fit specified parameters. Companies and taxonomy are MANY TO MANY relation. I&#39;m using Yii framework. And this is the code of my controller:

    public function actionFilters($list)
	{
		$companies = new CActiveDataProvider(&#39;Company&#39;, array(
			&#39;criteria&#39; =&gt; array(
				&#39;condition&#39;=&gt; &#39;type=0&#39;,
				&#39;together&#39; =&gt; true,
				&#39;order&#39;=&gt; &#39;rating DESC&#39;,
				&#39;with&#39;=&gt;array(
				&#39;taxonomy&#39;=&gt;array(
					&#39;condition&#39;=&gt;&#39;term_id IN (&#39;.$list.&#39;)&#39;,
					)
				),
			),
		));
		$this-&gt;render(&#39;index&#39;, array(
			&#39;companies&#39;=&gt;$companies,
		));
	}

Matching all values in IN clause

I have the following setup of a Scala application and a common core library:
root

     -&gt; /ApplicationA
       -&gt; /project
         -&gt; /build.sbt
     -&gt; /CoreLibrary
       -&gt; /project
         -&gt; /build.sbt

I want to add a reference from ApplicationA to CoreLibrary &#224; la Eclipse project reference, so that every time CoreLibrary changes ApplicationA is built as well. I&#180;ve tried the following contents of build.Scala for ApplicationA:

      val core = Project(
          id = &quot;platform-core&quot;,
          base = file(&quot;../CoreLibrary&quot;))
    
      val main = Project(id = &quot;application, base = file(&quot;.&quot;)).dependsOn(core)

However, when compiling ApplicationA SBT complains that a dependency can only be a subdirectory!!:

    java.lang.AssertionError: assertion failed: Directory C:\git\CoreLibrary is not contained in build root C:\git\ApplicationA

This seems completely straightforward, what&#39;s the correct way of having this project dependency?

How to reference external sbt project from another sbt project?

I have the following setup of a Scala application and a common core library:
root
<pre><code class="hljs language-rust"> -> /ApplicationA
 -> /project
 -> /build.sbt
 -> /CoreLibrary
 -> /project
 -> /build.sbt
</code></pre>
I want to add a reference from ApplicationA to CoreLibrary à la Eclipse project reference, so that every time CoreLibrary changes ApplicationA is built as well. I´ve tried the following contents of build.Scala for ApplicationA:
<pre><code class="hljs language-ini"> val core = Project(
 id = "platform-core",
 base = file("../CoreLibrary"))

 val main = Project(id = "application, base = file(".")).dependsOn(core)
</code></pre>
However, when compiling ApplicationA SBT complains that a dependency can only be a subdirectory!!:
<pre><code class="hljs language-php">java.lang.AssertionError: assertion failed: Directory C:\git\CoreLibrary is not contained in build root C:\git\ApplicationA
</code></pre>
This seems completely straightforward, what's the correct way of having this project dependency?

What is the difference between 

    object Application extends App {
       println(&quot;Hello World&quot;)
    }

and 

    object Application {
    	def main(args: Array[String]): Unit = {
    		println(&quot;Hello World&quot;);
    	}
    }



Difference between using App trait and main method in scala

When do you choose to type a given function&#39;s return type as `Seq` vs `Iterable` vs `Traversable` (or alternatively even deeper within `Seq`&#39;s hierarchy)?

How do you make that decision? We have a lot of code that returns `Seq`s by default (usually starting from results of a DB query and successive transformations). I tend to want to make the return types `Traversable` by default and `Seq` when specifically expecting a given order. But I don&#39;t have a strong justification for doing so.

I am perfectly familiar with the definition of each trait, so please don&#39;t answer with defining the terms.

scala, guidelines on return type - when prefer seq, iterable, traversable

When I&#39;m trying to affect a value of type String in a field of type Option[String] I get the following error :


    type mismatch; found : String required: Option[String]


How can I affect value `myValue:String` into field `myField:Option[String]` ?

How to set a String in a Option[String]?

I am trying to issue a simple POST request to a webservice which returns some XML in Scala.

It seems that [Dispatch][1] is the standard library used for this task, but I cannot find documentation for it. The main site, which I link above, explains at length what is a promise and how to do asynchronous programming, but does not actually document the API. There is a [periodic table][2] - which looks a bit scary - but it only seems useful to people who already know what to do and only need a reminder for the cryptic syntax.

It also seems that [Scalaz has some facility for HTTP][3], but I cannot find any documentation for it either.


  [1]: http://dispatch.databinder.net/Dispatch.html
  [2]: http://www.flotsam.nl/dispatch-periodic-table.html
  [3]: http://scalaz.github.com/scalaz/scalaz-2.9.1-6.0.4/doc.sxr/scalaz/http/request/Method.scala.html

Doing HTTP request in Scala

I am really interested in finding out where the differences are, and more generally, to identify canonical use cases where HLists cannot be used (or rather, don&#39;t yield any benefits over regular lists).

(I am aware that there are 22 (I believe) ``TupleN`` in Scala, whereas one only needs a single HList, but that is not the kind of conceptual difference I am interested in.)

I&#39;ve marked a couple of questions in the text below. It might not actually be necessary to answer them, they are more meant to point out things that are unclear to me, and to guide the discussion in certain directions.

### Motivation

I&#39;ve recently seen a couple of answers on SO where people suggested to use HLists (for example, as provided by [Shapeless][1]), including a deleted answer to [this question][2]. It gave rise to [this discussion][3], which in turn sparked this question.

### Intro

It seems to me, that hlists are only useful when you know the number of elements and their precise types statically. The number is actually not crucial, but it seems unlikely that you ever need to generate a list with elements of varying but statically precisely known types, but that you don&#39;t statically know their number. **Question 1:** Could you even write such an example, e.g., in a loop? My intuition is that having a statically precise hlist with a statically unknown number of arbitrary elements (arbitrary relative to a given class hierarchy) just isn&#39;t compatible.

### HLists vs. Tuples

If this is true, i.e, you statically know number and type - **Question 2:** why not just use an n-tuple? Sure, you can typesafely map and fold over an HList (which you can also, but **not** typesafely, do over a tuple with the help of ``productIterator``), but since number and type of the elements are statically known you could probably just access the tuple elements directly and perform the operations.

On the other hand, if the function ``f`` you map over an hlist is so generic that it accepts all elements - **Question 3:** why not use it via ``productIterator.map``? Ok, one interesting difference could come from method overloading: if we had several overloaded ``f``&#39;s, having the stronger type information provided by the hlist (in contrast to the productIterator) could allow the compiler to choose a more specific ``f``. However, I am not sure if that would actually work in Scala, since methods and functions are not the same.

### HLists and user input

Building on the same assumption, namely, that you need to know number and types of the elements statically - **Question 4:** can hlists be used in situations where the elements depend on any kind of user interaction? E.g., imagine populating an hlist with elements inside a loop; the elements are read from somewhere (UI, config file, actor interaction, network) until a certain condition holds. What would the type of the hlist be? Similar for an interface specification getElements: HList[...] that should work with lists of statically unknown length, and that allows component A in a system to get such a list of arbitrary elements from component B.
 
  [1]: https://github.com/milessabin/shapeless
  [2]: https://stackoverflow.com/questions/11815908/valid-type-casting-of-both-covariant-and-contravariant-class-at-runtime-in-scala
  [3]: https://chat.stackoverflow.com/rooms/14938/discussion-between-mhs-and-edmondo1984

Are HLists nothing more than a convoluted way of writing tuples?

I have installed sbt on Ubuntu.

    :~/bin/sbt/bin$ ls
    classes    sbt      sbt-launch.jar       target
    jansi.jar  sbt.bat  sbt-launch-lib.bash  win-sbt

However, whenever I try to launch sbt (from the same directory where sbt is located) it does not work:

    No command &#39;sbt&#39; found, did you mean:
     Command &#39;skt&#39; from package &#39;latex-sanskrit&#39; (universe)
     Command &#39;sb2&#39; from package &#39;scratchbox2&#39; (universe)
     Command &#39;sbd&#39; from package &#39;cluster-glue&#39; (main)
     Command &#39;mbt&#39; from package &#39;mbt&#39; (universe)
     Command &#39;sbmt&#39; from package &#39;atfs&#39; (universe)
     Command &#39;lbt&#39; from package &#39;lbt&#39; (universe)
     Command &#39;st&#39; from package &#39;suckless-tools&#39; (universe)
     Command &#39;sb&#39; from package &#39;lrzsz&#39; (universe)

I am new to linux and I have no idea how to tackle this issue.


Install sbt on ubuntu

How do I configure sbt to use a proxy?

For example, my build definition needs to connect to GitHub, specifying connection parameters for `http.proxy`, `http.proxyPort`, `user`, and `password`.

How would I pass in these settings to sbt?

Is there an easy way to switch between proxy/no-proxy settings for when I work from home?


How to use sbt from behind proxy?

Is there a way to build tests with SBT without running them?

My own use case is to run static analysis on the test code by using a scalac plugin. Another possible use case is to run some or all of the test code using a separate runner than the one built into SBT.

Ideally there would be a solution to this problem that applies to any SBT project. For example, Maven has a test-compile command that can be used just to compile the tests without running them. It would be great if SBT had the same thing.

Less ideal, but still very helpful, would be solutions that involve modifying the project&#39;s build files.


How to compile tests with SBT without running them

I&#39;m adding the Joda Time repository to SBT with

    libraryDependencies ++= Seq(
      &quot;joda-time&quot;         % &quot;joda-time&quot;           % &quot;2.1&quot;
    )

Then I merrily use it like this:

     val ymd = org.joda.time.format.DateTimeFormat.forPattern(&quot;yyyyMMdd&quot;)
      ymd.parseDateTime(&quot;20121212&quot;)

But, when I compile the project in SBT, I get a nasty:

    [warn] Class org.joda.convert.FromString not found - continuing with a stub.
    [warn] Caught: java.lang.NullPointerException while parsing annotations in /home/jack/.ivy2/cache/joda-time/joda-time/jars/joda-time-2.1.jar(org/joda/time/DateTime.class)
    [error] error while loading DateTime, class file &#39;/home/jack/.ivy2/cache/joda-time/joda-time/jars/joda-time-2.1.jar(org/joda/time/DateTime.class)&#39; is broken
    [error] (class java.lang.RuntimeException/bad constant pool tag 10 at byte 42)

I tried the 2.0 version of joda-time, but get the same error.


Class broken error with Joda Time using Scala

I am using SBT 0.12.0. I have read other answers on stack overflow and followed them, however none of them helps, for example:

 - create `ForkRun` class - I have not observed any forked process during my usage of sbt
 - set environment variable `JAVA_OPTS` - it is set but sbt&#39;s process command line does not seem to use it at all.
 - `sbt -J-Xmx2G` appends the parameter to sbt process command line, however the old value `-Xmx1536m` is used by sbt instead of the appended parameter.

Am I missing something? How do I set heap size for sbt 0.12, when doing both testing and `run`?

Content Type	Original Author	Original Content on Stackoverflow
Question	Diego	View Question on Stackoverflow
Solution 1 - Scala	jwinandy	View Answer on Stackoverflow
Solution 2 - Scala	Maxence	View Answer on Stackoverflow
Solution 3 - Scala	Mustafa	View Answer on Stackoverflow

How to reference external sbt project from another sbt project?

Scala Problem Overview

Scala Solutions

Solution 1 - Scala

Solution 2 - Scala

Solution 3 - Scala

Matching all values in IN clause

How do you use object initializers for a list of key value pairs?

Attributions