Search Results

Search found 1752 results on 71 pages for 'scala macros'.

Page 5/71 | < Previous Page | 1 2 3 4 5 6 7 8 9 10 11 12  | Next Page >

• Naming case classes in Scala.

  - by Lukasz Lew

  I tend to have this redundant naming in case classes: abstract class MyTree case class MyTreeNode (...) case class MyTreeLeaf (...) Isn't it possible to define Node and Leaf inside of MyTree? What are best practices here?

  Read the article

• How to unimport String "+" operator in Scala?

  - by Alex R

  I'm writing a DSL where the "+" operator is strictly numeric, and the String "+" operator is messing up my implicit conversions. What's the syntax for unimporting an operator of the String class? Thanks

  Read the article

• Why isn't VIM storing macros across sessions?

  - by dotancohen

  In VIM 7.3 on Ubuntu Server 12.04.1, VIM forgets macros and registers after closing. I do have set nocompatible in .vimrc and the command :set viminfo? gives this result: viminfo='100,<50,s10,h What might be preventing the macros and registers from being stored across close / open? Note that I am not interested in storing mappings for long term use in .vimrc. Rather, sometimes (such as during refactoring) I need to perform a simple operation on a few files and I find it easier to do in VIM than with Perl. I just need the macros and registers stored across open / close, which I do have working on other servers. Thanks.

  Read the article

• Can't update scala on Gentoo

  - by xhochy

  As I wanted to test Scala 2.9.2 on my gentoo system I tried updated the package but ended up with this error. I can't figure out where the problem may be: Calculating dependencies ...... done! >>> Verifying ebuild manifests >>> Jobs: 0 of 1 complete, 1 running Load avg: 0.23, 0.16, 0.20 >>> Emerging (1 of 1) dev-lang/scala-2.9.2 >>> Jobs: 0 of 1 complete, 1 running Load avg: 0.23, 0.16, 0.20 >>> Failed to emerge dev-lang/scala-2.9.2, Log file: >>> Jobs: 0 of 1 complete, 1 running Load avg: 0.23, 0.16, 0.20 >>> '/var/tmp/portage/dev-lang/scala-2.9.2/temp/build.log' >>> Jobs: 0 of 1 complete, 1 running Load avg: 0.23, 0.16, 0.20 >>> Jobs: 0 of 1 complete, 1 running, 1 failed Load avg: 0.23, 0.16, 0.20 >>> Jobs: 0 of 1 complete, 1 failed Load avg: 0.23, 0.16, 0.20 * Package: dev-lang/scala-2.9.2 * Repository: gentoo * Maintainer: [email protected] * USE: amd64 elibc_glibc kernel_linux multilib userland_GNU * FEATURES: sandbox [01m[31;06m!!! ERROR: Couldn't find suitable VM. Possible invalid dependency string. Due to jdk-with-com-sun requiring a target of 1.7 but the virtual machines constrained by virtual/jdk-1.6 and/or this package requiring virtual(s) jdk-with-com-sun[0m * Unable to determine VM for building from dependencies: NV_DEPEND: virtual/jdk:1.6 java-virtuals/jdk-with-com-sun !binary? ( dev-java/ant-contrib:0 ) app-arch/xz-utils >=dev-java/java-config-2.1.9-r1 source? ( app-arch/zip ) >=dev-java/ant-core-1.7.0 dev-java/ant-nodeps >=dev-java/javatoolkit-0.3.0-r2 >=dev-lang/python-2.4 * ERROR: dev-lang/scala-2.9.2 failed (setup phase): * Failed to determine VM for building. * * Call stack: * ebuild.sh, line 93: Called pkg_setup * scala-2.9.2.ebuild, line 43: Called java-pkg-2_pkg_setup * java-pkg-2.eclass, line 53: Called java-pkg_init * java-utils-2.eclass, line 2187: Called java-pkg_switch-vm * java-utils-2.eclass, line 2674: Called die * The specific snippet of code: * die "Failed to determine VM for building." * * If you need support, post the output of `emerge --info '=dev-lang/scala-2.9.2'`, * the complete build log and the output of `emerge -pqv '=dev-lang/scala-2.9.2'`. !!! When you file a bug report, please include the following information: GENTOO_VM= CLASSPATH="" JAVA_HOME="" JAVACFLAGS="" COMPILER="" and of course, the output of emerge --info * The complete build log is located at '/var/tmp/portage/dev-lang/scala-2.9.2/temp/build.log'. * The ebuild environment file is located at '/var/tmp/portage/dev-lang/scala-2.9.2/temp/die.env'. * Working directory: '/var/tmp/portage/dev-lang/scala-2.9.2' * S: '/var/tmp/portage/dev-lang/scala-2.9.2/work/scala-2.9.2-sources' * Messages for package dev-lang/scala-2.9.2: * Unable to determine VM for building from dependencies: * ERROR: dev-lang/scala-2.9.2 failed (setup phase): * Failed to determine VM for building. * * Call stack: * ebuild.sh, line 93: Called pkg_setup * scala-2.9.2.ebuild, line 43: Called java-pkg-2_pkg_setup * java-pkg-2.eclass, line 53: Called java-pkg_init * java-utils-2.eclass, line 2187: Called java-pkg_switch-vm * java-utils-2.eclass, line 2674: Called die * The specific snippet of code: * die "Failed to determine VM for building." * * If you need support, post the output of `emerge --info '=dev-lang/scala-2.9.2'`, * the complete build log and the output of `emerge -pqv '=dev-lang/scala-2.9.2'`. * The complete build log is located at '/var/tmp/portage/dev-lang/scala-2.9.2/temp/build.log'. * The ebuild environment file is located at '/var/tmp/portage/dev-lang/scala-2.9.2/temp/die.env'. * Working directory: '/var/tmp/portage/dev-lang/scala-2.9.2' * S: '/var/tmp/portage/dev-lang/scala-2.9.2/work/scala-2.9.2-sources' The following eix output may help: % eix java-virtuals/jdk-with-com-sun [I] java-virtuals/jdk-with-com-sun Available versions: 20111111 {{ELIBC="FreeBSD"}} Installed versions: 20111111(16:08:51 18/04/12)(ELIBC="-FreeBSD") Homepage: http://www.gentoo.org Description: Virtual ebuilds that require internal com.sun classes from a JDK Both virtual jdks 1.6 and 1.7 are installed: % eix virtual/jdk [I] virtual/jdk Available versions: (1.4) ~1.4.2-r1[1] (1.5) 1.5.0 ~1.5.0-r3[1] (1.6) 1.6.0 1.6.0-r1 (1.7) (~)1.7.0 Installed versions: 1.6.0-r1(1.6)(23:22:48 10/11/12) 1.7.0(1.7)(23:21:09 10/11/12) Description: Virtual for JDK [1] "java-overlay" /var/lib/layman/java-overlay

  Read the article

• scala syntax highlighting in bluefish

  - by Synesso

  Scala comes packaged with bluefish syntax config in misc/scala-tool-support/bluefish/ I have attempted to configure this, as per the README, but there is no effect. cp ~/.bluefish/highlighting ~/.bluefish/highlighting_ cat ~/.bluefish/highlighting_ /opt/scala/scala-2.7.7.final/misc/scala-tool-support/bluefish/highlighting > ~/.bluefish/highlighting I have ensured highlighting is turned on in the bluefish config. I have not used bluefish before and am trying it for the first time because there is syntax highlighting support for it. The README says any file I open that has a .scala extension will have the scala highlighting applied. Instead I see no highlighting.

  Read the article

• Scala type inference failure on "? extends" in Java code

  - by oxbow_lakes

  I have the following simple Java code: package testj; import java.util.*; public class Query<T> { private static List<Object> l = Arrays.<Object>asList(1, "Hello", 3.0); private final Class<? extends T> clazz; public static Query<Object> newQuery() { return new Query<Object>(Object.class); } public Query(Class<? extends T> clazz) { this.clazz = clazz; } public <S extends T> Query<S> refine(Class<? extends S> clazz) { return new Query<S>(clazz); } public List<T> run() { List<T> r = new LinkedList<T>(); for (Object o : l) { if (clazz.isInstance(o)) r.add(clazz.cast(o)); } return r; } } I can call this from Java as follows: Query<String> sq = Query.newQuery().refine(String.class); //NOTE NO <String> But if I try and do the same from Scala: val sq = Query.newQuery().refine(classOf[String]) I get the following error: error: type mismatch found :lang.this.class[scala.this.Predef.String] required: lang.this.class[?0] forSome{ type ?0 <: ? } val sq = Query.newQuery().refine(classOf[String]) This is only fixed by the insertion of the correct type parameter! val sq = Query.newQuery().refine[String](classOf[String]) Why can't scala infer this from my argument? Note I am using Scala 2.7

  Read the article

• Are C++ templates just a kind of glorified macros?

  - by Gulshan

  From different comparisons among C++ templates and C#/Java generics like this one- http://stackoverflow.com/questions/31693/what-are-the-differences-between-generics-in-c-and-java-and-templates-in-c/31929#31929 I have a got a perception that, C++ templates are implemented by some kind of preprocessing, not compiling. In other words, they are just a kind of C macros. Is this right? Then I felt that, if C++ templates are implemented by preprocessing, dynamic linking(.dll) cannot be used. A quick google search also supports this. And lastly, how can we use macros in C to deliver C++ templates like functionalities? Another thing came in my mind about templates similar to some kind of preprocessor that, there can be integers passed as arguments to some templates. And it even supports kind of recursion. But the recursion is not in the assembly/machine code. So, am I wrong calling templates glorified macros? Unlike normal macros, it has some superior abilities. But isn't it a kind of preprocessing?

  Read the article

• What's the problem with Scala's XML literals?

  - by Oak

  In this post, Martin (the language's head honcho) writes: [XML literals] Seemed a great idea at the time, now it sticks out like a sore thumb. I believe with the new string interpolation scheme we will be able to put all of XML processing in the libraries, which should be a big win. Being interested in language design myself, I'm wondering: Why does he write that it was a mistake to incorporate XML literals into the language? What is the controversy regarding this feature?

  Read the article

• Should Scala IDE Worksheets be part of your open git repository?

  - by JacobusR

  Those familiar with Scala IDE will know about the great testing environment offered by the Scala Worksheet. You can scribble and scratch, much like in the REPL, but with all the goodness added by the IDE as a whole (refactoring, saving, error checking, etc). When you create a worksheet, it is created with the .sc extension, and also creates a artifact under a hidden directory called .worksheet. This is all fine and dandy, but should one include these in your public .git repositories? People who does not use Scala IDE (or older versions) may find these files confusing. On the other hand, making some of your experiments public to developers who are using Scala IDE, may give them a quick start into experimenting and learning the project.

  Read the article

• Scala libraries and frameworks

  - by folone

  Each technology is powerful with libraries and frameworks, written for it. I understand, that Scala is able to use libraries and frameworks, written for Java. But there are already some frameworks, written for Scala in Scala. Like, for example: Lift Framework ScalaTest Scalaz Do you know any more great libraries and frameworks for Scala, written in Scala?

  Read the article

• Scala xhtml attribute breaks because of a question mark

  - by portoalet

  I had a problem with <iframe id="iframe1" src='http://stockcharts.com/h-sc/ui?s=MT&p=D&yr=2&mn=0&dy=0&id=p43321191731' width="300px" height="300px"></iframe> in Lift web framework (Scala) version Message: java.util.NoSuchElementException scala.RandomAccessSeq$$anon$13.next(RandomAccessSeq.scala:165) scala.xml.parsing.MarkupParser$class.normalizeAttributeValue(MarkupParser.scala:1191) It turned out the question mark ? in the iframe src attribute caused this. What can I do to fix this quickly?

  Read the article

• Can you return an assignable lvalue in Scala?

  - by Alex R

  (note, lvalue is actually a term from the C grammar, I don't know what it's called in Scala!) Trying to learn Scala... this evening I'm working on an internal DSL for a dynamically scoped language that might resemble PHP syntax. My REPL is: Welcome to Scala version 2.7.6.final (Java HotSpot(TM) Client VM, Java 1.6.0). I have some made-up example code: class $(any: Any) { def update(sym: Symbol, any: Any) { println("line 2 executed");} def -(sym: Symbol) : $ = { println("line 1 executed"); return this } def update(any: Any) { println("line 3 executed");} } The following works as expected: scala var a = new $(0) a: $ = $@19238ad scala a('x) = "blah" line 2 executed On the other hand, why does the following not invoke the 1-parameter update method? scala a = 1 :6: error: type mismatch; found : Int(1) required: $ a = 1 ^ Ultimately, I would like this to work: a-'x = "blah" Thanks

  Read the article

• How to use Scala interpreter options with SBT?

  - by John Threepwood

  When using the Scala interpreter, one could start it with an option like: C:\Users\John>scala -unchecked 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> When using sbt, how can one start the Scala interpreter with options ? The following try will not work: C:\Users\John\Test Scala Project 1>sbt [...] [info] Loading global plugins from C:\Users\John\.sbt\plugins [info] Set current project to default-8d4ecc (in build file:/C:/Users/John/Tes t%20Scala%20Project%201/) > console -unchecked [error] Expected end of input. [error] console -unchecked [error] ^ With Google & Co I could not figure out how to do this from within the sbt shell. Does anyone know ?

  Read the article

• Scala class to implement two Java Interfaces - how?

  - by puudeli

  Hi, I have just started learning Scala and I'm now wondering how I could implement two different Java interfaces with one Scala class? Let's say I have the following interfaces written in Java public interface EventRecorder { public void abstract record(Event event); } public interface TransactionCapable { public void abstract commit(); } But a Scala class can extend only one class at a time. How can I have a Scala class that could fulfill both contracts? Do I have to map those interfaces into traits? Note, my Scala classes would be used from Java as I am trying to inject new functionality written in Scala into an existing Java application. And the existing framework expects that both interface contracts are fulfilled.

  Read the article

• scala REPL is slow on vista

  - by Jacques René Mesrine

  I installed scala-2.8.0.RC3 by extracting the tgz file into my cygwin (vista) home directory. I made sure to set $PATH to scala-2.8.0.RC3/bin. I start the REPL by typing: $ scala Welcome to Scala version 2.8.0.RC3 (Java HotSpot(TM) Client VM, Java 1.6.0_20). Type in expressions to have them evaluated. Type :help for more information. scala> Now when I tried to enter an expression scala> 1 + 'a' the cursor hangs there without any response. Granted that I have chrome open with a million tabs and VLC playing in the background, but CPU utilization was 12% and virtual memory was about 75% utilized. What's going on ? Do I have to set the CLASSPATH or perform other steps.

  Read the article

• Scala: Mixing traits with private fields

  - by Vilius Normantas

  It's not much of a question, it's rather my excitement that it's possible at all! I wrote this little example just to prove the opposite - I expected either a compiler error or one of the values (111 or 222, I wasn't sure). scala> trait T1 { private val v = 111; def getValueT1 = v } scala> trait T2 { private val v = 222; def getValueT2 = v } scala> class T12 extends T1 with T2 scala> val t = new T12 scala> t.getValueT1 res9: Int = 111 scala> t.getValueT2 res10: Int = 222 Why doesn't the v get overridden? Off course this works only as long as vs are private, but still.

  Read the article

• Scala Eclipse IDE suddenly ignoring breakpoints

  - by malsmith

  I've been using Scala 2.8RC1 and Scala Eclipse plugin for 2.8 RC1 happily for a few days. However, last night after adding a couple jar files to my environment (apache http client jars) the debugger just stopped stopping at breakpoints in scala code. Java code stops fine at breakpoints. I tried creating a new mimimal scala app breakpoints don't stop. I've tried switching to sun-jre-1.6.0.20 from the openjdk-1.6.18 I had been using. I've switched to the scala 2.8 nightly and also eclipse plugin for scala nightly builds. No luck. I would greatly appreciate ideas for fixes. Rather frustrating as the initial experience with 2.8 was really great.

  Read the article

• Scala :: operator, how it works?

  - by Felix

  Hello Guys, in Scala, I can make a caseclass case class Foo(x:Int) and then put it in a list like so: List(Foo(42)) Now, nothing strange here. The following is strange to me. The operator :: is a function on a list, right? With any function with 1 argument in Scala, I can call it with infix notation. An example is 1 + 2 is a function (+) on the object Int. The class Foo I just defined does not have the :: operator, so how is the following possible: Foo(40) :: List(Foo(2)) ? In scala 2.8 rc1, I get the following output from the interactive prompt: scala> case class Foo(x:Int) defined class Foo scala> Foo(40) :: List(Foo(2)) res2: List[Foo] = List(Foo(40), Foo(2)) scala> I can go on and use it, but if someone can explain it I will be glad :)

  Read the article

• Simple Scala syntax - trying to define "==" operator - what am I missing?

  - by Alex R

  While experimenting with some stuff on the REPL, I got to a point where I needed something like this: scala class A(x:Int) { println(x); def ==(a:A) : Boolean = { this.x == a.x; } } Just a simple class with an "==" operator. Why doesn't it work??? Here's the result: :10: error: type mismatch; found : A required: ?{val x: ?} Note that implicit conversions are not applicable because they are ambiguous: both method any2ArrowAssoc in object Predef of type [A](x: A)ArrowAssoc[A] and method any2Ensuring in object Predef of type [A](x: A)Ensuring[A] are possible conversion functions from A to ?{val x: ?} class A(x:Int) { println(x); def ==(a:A) : Boolean = { this.x == a.x; } } ^ This is scala 2.8 RC1. Thanks

  Read the article

• In Scala 2.8 collections, why was the Traversable type added above Iterable?

  - by Seth Tisue

  I know that to be Traversable, you need only have a foreach method. Iterable requires an iterator method. Both the Scala 2.8 collections SID and the "Fighting Bitrot with Types" paper are basically silent on the subject of why Traversable was added. The SID only says "David McIver... proposed Traversable as a generalization of Iterable." I have vaguely gathered from discussions on IRC that it has to do with reclaiming resources when traversal of a collection terminates? The following is probably related to my question. There are some odd-looking function definitions in TraversableLike.scala, for example: def isEmpty: Boolean = { var result = true breakable { for (x <- this) { result = false break } } result } I assume there's a good reason that wasn't just written as: def isEmpty: Boolean = { for (x <- this) return false true }

  Read the article

• Why is this Scala example of implicit paremeter not working?

  - by Alex R

  simple REPL test... def g(a:Int)(implicit b:Int) = {a+b} Why do neither of these attempted usages work? 1. scala class A { var b:Int =8; var c = g(2) } :6: error: could not find implicit value for parameter b: Int class A { var b:Int =8; var c = g(2) } 2. scala class A(var b:Int) { var c = g(2) } :6: error: could not find implicit value for parameter b: Int class A(var b:Int) { var c = g(2) } ^ Thanks

  Read the article

• DocBook macros?

  - by cibercitizen1

  Is there any way of defining macros (like tex macros o latex defines) in DocBook documents? DocBook is very verbose, and macros would help a lot. I didn't find them in quickstart tutorials. If so, could anyone provide a simple example or a link to? Thanks

  Read the article

• Macros no longer working in VS2005

  - by NPVN

  I'm using VS2005 on Vista. I'm using some macros, but now they have suddenly stopped working. No error messages of any kind. I am not aware of having done anything that could trigger this. I have made sure that "Allow macros to run" is checked in Tools-Options-Addin/Macro Security. I have tried running the macros from a keyboard shortcut, from the Macro Explorer, and from the Macros IDE, all in vain: The little spinning icon displays shortly (<1 sec) and then disappears without the macro being executed. I have tried putting a breakpoint on the first line of the macro and then executing it from the main IDE, with no effect (the breakpoint isn't hit). I have tried the same from the Macro IDE: The state changes to "running", but the breakpoint isn't hit. I have to break the execution manually. Any ideas?

  Read the article

• Documentation concerning platform-specific macros in Linux/POSIX

  - by Nubok

  When compiling a C/C++ program under Windows using Visual Studio (or a compiler that tries to be compatible) there is a predefined macro _WIN32 (Source: http://msdn.microsoft.com/en-us/library/b0084kay.aspx) that you can use for platform-specific #ifdef-s. What I am looking for is an analogon under Linux: a macro which tells me that I am compiling for Linux/an OS that claims to be (more or less) POSIX-compatible. So I looked into gcc documentation and found this: http://gcc.gnu.org/onlinedocs/cpp/System_002dspecific-Predefined-Macros.html Applied to my program, the following macros (gcc 4.4.5 - Ubuntu 10.10) looked promising (I hope that I didn't drop an important macro): #define __USE_BSD 1 #define __unix__ 1 #define __linux 1 #define __unix 1 #define __linux__ 1 #define _POSIX_SOURCE 1 #define __STDC_HOSTED__ 1 #define __STDC_IEC_559__ 1 #define __gnu_linux__ 1 #define __USE_SVID 1 #define __USE_XOPEN2K 1 #define __USE_POSIX199506 1 #define _G_USING_THUNKS 1 #define __USE_XOPEN2K8 1 #define _BSD_SOURCE 1 #define unix 1 #define linux 1 #define __USE_POSIX 1 #define __USE_POSIX199309 1 #define __SSP__ 1 #define _SVID_SOURCE 1 #define _G_HAVE_SYS_CDEFS 1 #define __USE_POSIX_IMPLICITLY 1 Where do I find a detailed documentation of them - as to the mentioned Windows-specific macros above? Additionally I'd be interested in macros normally defined for other POSIX-compliant operating systems as *BSD etc.

  Read the article

• Programmatically Determine If An Excel File (.xls) Contains Macros

  - by Gkakk McJkakk

  Is there any way to programmatically determine if an .xls contains macros, without actually opening it in Excel? Also are there any methods to examine which certificate (including timestamp cert) these macros are signed with? Again without using Excel. I'm wondering in particular if there are any strings that always show up in the raw data of an Excel file when macros are present.

  Read the article

< Previous Page | 1 2 3 4 5 6 7 8 9 10 11 12  | Next Page >