Search Results

Search found 2945 results on 118 pages for 'scala designer'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 27/118 | < Previous Page | 23 24 25 26 27 28 29 30 31 32 33 34  | Next Page >

  • scala 2.8.0.RC2 compiler problem on pattern matching statement?

    - by gruenewa
    Why does the following module not compile on Scala 2.8.RC[1,2]? object Test { import util.matching.Regex._ val pVoid = """\s*void\s*""".r val pVoidPtr = """\s*(const\s+)?void\s*\*\s*""".r val pCharPtr = """\s*(const\s+)GLchar\s*\*\s*""".r val pIntPtr = """\s*(const\s+)?GLint\s*\*\s*""".r val pUintPtr = """\s*(const\s+)?GLuint\s*\*\s*""".r val pFloatPtr = """\s*(const\s+)?GLfloat\s*\*\s*""".r val pDoublePtr = """\s*(const\s+)?GLdouble\s*\*\s*""".r val pShortPtr = """\s*(const\s+)?GLshort\s*\*\s*""".r val pUshortPtr = """\s*(const\s+)?GLushort\s*\*\s*""".r val pInt64Ptr = """\s*(const\s+)?GLint64\s*\*\s*""".r val pUint64Ptr = """\s*(const\s+)?GLuint64\s*\*\s*""".r def mapType(t: String): String = t.trim match { case pVoid() => "Unit" case pVoidPtr() => "ByteBuffer" case pCharPtr() => "CharBuffer" case pIntPtr() | pUintPtr() => "IntBuffer" case pFloatPtr() => "FloatBuffer" case pShortPtr() | pUshortPtr() => "ShortBuffer" case pDoublePtr() => "DoubleBuffer" case pInt64Ptr() | pUint64Ptr() => "LongBuffer" case x => x } }

    Read the article

  • Scala, represent pattern of boolean tuple into something else.

    - by Berlin Brown
    This is a cellular automata rule (input Boolean == Left, Center, Right Cell) and output Boolean . What is a better way to represent this in Scala. trait Rule { def ruleId() : Int def rule(inputState:(Boolean, Boolean, Boolean)) : Boolean override def toString : String = "Rule:" + ruleId } class Rule90 extends Rule { def ruleId() = 90 def rule(inputState:(Boolean, Boolean, Boolean)) : Boolean = { // Verbose version, show all 8 states inputState match { case (true, true, true) => false case (true, false, true) => false case (false, true, false) => false case (false, false, false) => false case _ => true } } }

    Read the article

  • In scala can I pass repeated parameters to other methods?

    - by Fred Haslam
    Here is something I can do in java, take the results of a repeated parameter and pass it to another method: public void foo(String ... args){bar(args);} public void bar(String ... args){System.out.println("count="+args.length);} In scala it would look like this: def foo(args:String*) = bar(args) def bar(args:String*) = println("count="+args.length) But this won't compile, the bar signature expects a series of individual strings, and the args passed in is some non-string structure. For now I'm just passing around arrays. It would be very nice to use starred parameters. Is there some way to do it?

    Read the article

  • How is `toString` in `scala.Enumeration$Value` implemented?

    - by Red Hyena
    I have an enum Fruit defined as: object Fruit extends Enumeration { val Apple, Banana, Cherry = Value } Now printing values of this enum, on Scala 2.7.x gives: scala> Fruit foreach println line1$object$$iw$$iw$Fruit(0) line1$object$$iw$$iw$Fruit(1) line1$object$$iw$$iw$Fruit(2) However the same operation on Scala 2.8 gives: scala> Fruit foreach println warning: there were deprecation warnings; re-run with -deprecation for details Apple Banana Cherry My question is: How is the method toString in Enumeration in Scala 2.8 is implemented? I tried looking into the source of Enumeration but couldn't understand anything.

    Read the article

  • How can I pass a type as a parameter in scala?

    - by rsan
    I'm having a really hard time trying to figure out how can I store or pass a type in scala. What I want to achive is something like this: abstract class Foo( val theType : type ) object Foo{ case object Foo1 extends Foo(String) case object Foo2 extends Foo(Long) } So at some point I can do this: theFoo match{ case String => "Is a string" case Long => "Is a long" } and when obtaining the object being able to cast it: theFoo.asInstanceOf[Foo1.theType] Is this possible? If is possible, is a good aproach? What I'm trying to achieve ultimately is writing a pseudo schema for byte stream treatment. E.g if I have an schema Array(Foo1,Foo1,Foo2,Foo3,Foo1) I could parse Arrays of bytes that complain with that schema, if at some point I have a different stream of bytes I could just write a new schema Array(Foo3, Foo4, Foo5) without having to reimplement parsing logic. Regards,

    Read the article

  • scala coalesces multiple function call parameters into a Tuple -- can this be disabled?

    - by landon9720
    This is a troublesome violation of type safety in my project, so I'm looking for a way to disable it. It seems that if a function takes an AnyRef (or a java.lang.Object), you can call the function with any combination of parameters, and Scala will coalesce the parameters into a Tuple object and invoke the function. In my case the function isn't expecting a Tuple, and fails at runtime. I would expect this situation to be caught at compile time. object WhyTuple { def main(args: Array[String]): Unit = { fooIt("foo", "bar") } def fooIt(o: AnyRef) { println(o.toString) } } Output: (foo,bar)

    Read the article

  • How to yield a single element from for loop in scala?

    - by Julio Faerman
    Much like this question: Functional code for looping with early exit Say the code is def findFirst[T](objects: List[T]):T = { for (obj <- objects) { if (expensiveFunc(obj) != null) return /*???*/ Some(obj) } None } How to yield a single element from a for loop like this in scala? I do not want to use find, as proposed in the original question, i am curious about if and how it could be implemented using the for loop. * UPDATE * First, thanks for all the comments, but i guess i was not clear in the question. I am shooting for something like this: val seven = for { x <- 1 to 10 if x == 7 } return x And that does not compile. The two errors are: - return outside method definition - method main has return statement; needs result type I know find() would be better in this case, i am just learning and exploring the language. And in a more complex case with several iterators, i think finding with for can actually be usefull. Thanks commenters, i'll start a bounty to make up for the bad posing of the question :)

    Read the article

  • Idiomatic Scala way to deal with base vs derived class field names?

    - by Gregor Scheidt
    Consider the following base and derived classes in Scala: abstract class Base( val x : String ) final class Derived( x : String ) extends Base( "Base's " + x ) { override def toString = x } Here, the identifier 'x' of the Derived class parameter overrides the field of the Base class, so invoking toString like this: println( new Derived( "string" ).toString ) returns the Derived value and gives the result "string". So a reference to the 'x' parameter prompts the compiler to automatically generate a field on Derived, which is served up in the call to toString. This is very convenient usually, but leads to a replication of the field (I'm now storing the field on both Base and Derived), which may be undesirable. To avoid this replication, I can rename the Derived class parameter from 'x' to something else, like '_x': abstract class Base( val x : String ) final class Derived( _x : String ) extends Base( "Base's " + _x ) { override def toString = x } Now a call to toString returns "Base's string", which is what I want. Unfortunately, the code now looks somewhat ugly, and using named parameters to initialize the class also becomes less elegant: new Derived( _x = "string" ) There is also a risk of forgetting to give the derived classes' initialization parameters different names and inadvertently referring to the wrong field (undesirable since the Base class might actually hold a different value). Is there a better way? Edit: To clarify, I really only want the Base values; the Derived ones just seem necessary for initializing the Base ones. The example only references them to illustrate the ensuing issues. It might be nice to have a way to suppress automatic field generation if the derived class would otherwise end up hiding a base class field.

    Read the article

  • How can I get VS2008 winforms designer to render a Form that implements an abstract base class

    - by BeowulfOF
    Hi, I engadged a problem with inherited Controls in WinForms, and need some advice on it. I do use a base class for items in a List (selfmade GUI list made of a panel) and some inherited controls that are for each type of data that could be added to the list. There was no problem with it, but I know found out, that it would be right, to make the base-control an abstract class, since it has methods, that need to be implemented in all inherited controls, called from the code inside the base-control, but must not and can not be implemented in the base class. When I mark the base-control as abstract, the VS2008 Designer refuses to load the window. Is there any way to get the Designer work with the base-control made abstract?

    Read the article

  • How to flatten list of options using higher order functions?

    - by Synesso
    Using Scala 2.7.7: If I have a list of Options, I can flatten them using a for-comprehension: val listOfOptions = List(None, Some("hi"), None) listOfOptions: List[Option[java.lang.String]] = List(None, Some(hi), None) scala> for (opt <- listOfOptions; string <- opt) yield string res0: List[java.lang.String] = List(hi) I don't like this style, and would rather use a HOF. This attempt is too verbose to be acceptable: scala> listOfOptions.flatMap(opt => if (opt.isDefined) Some(opt.get) else None) res1: List[java.lang.String] = List(hi) Intuitively I would have expected the following to work, but it doesn't: scala> List.flatten(listOfOptions) <console>:6: error: type mismatch; found : List[Option[java.lang.String]] required: List[List[?]] List.flatten(listOfOptions) Even the following seems like it should work, but doesn't: scala> listOfOptions.flatMap(_: Option[String]) <console>:6: error: type mismatch; found : Option[String] required: (Option[java.lang.String]) => Iterable[?] listOfOptions.flatMap(_: Option[String]) ^ The best I can come up with is: scala> listOfOptions.flatMap(_.toList) res2: List[java.lang.String] = List(hi) ... but I would much rather not have to convert the option to a list. That seems clunky. Any advice?

    Read the article

  • How to further improve error messages in Scala parser-combinator based parsers?

    - by rse
    I've coded a parser based on Scala parser combinators: class SxmlParser extends RegexParsers with ImplicitConversions with PackratParsers { [...] lazy val document: PackratParser[AstNodeDocument] = ((procinst | element | comment | cdata | whitespace | text)*) ^^ { AstNodeDocument(_) } [...] } object SxmlParser { def parse(text: String): AstNodeDocument = { var ast = AstNodeDocument() val parser = new SxmlParser() val result = parser.parseAll(parser.document, new CharArrayReader(text.toArray)) result match { case parser.Success(x, _) => ast = x case parser.NoSuccess(err, next) => { tool.die("failed to parse SXML input " + "(line " + next.pos.line + ", column " + next.pos.column + "):\n" + err + "\n" + next.pos.longString) } } ast } } Usually the resulting parsing error messages are rather nice. But sometimes it becomes just sxml: ERROR: failed to parse SXML input (line 32, column 1): `"' expected but `' found ^ This happens if a quote characters is not closed and the parser reaches the EOT. What I would like to see here is (1) what production the parser was in when it expected the '"' (I've multiple ones) and (2) where in the input this production started parsing (which is an indicator where the opening quote is in the input). Does anybody know how I can improve the error messages and include more information about the actual internal parsing state when the error happens (perhaps something like a production rule stacktrace or whatever can be given reasonably here to better identify the error location). BTW, the above "line 32, column 1" is actually the EOT position and hence of no use here, of course.

    Read the article

  • Some VS 2010 RC Updates (including patches for Intellisense and Web Designer fixes)

    [In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu] We are continuing to make progress on shipping Visual Studio 2010.  Id like to say a big thank you to everyone who has downloaded and tried out the VS 2010 Release Candidate, and especially to those who have sent us feedback or reported issues with it. This data has been invaluable in helping us find and fix remaining bugs before we ship the final release. Last...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

    Read the article

  • OWB 11gR2 - Find and Search Metadata in Designer

    - by David Allan
    Here are some tools and techniques for finding objects, specifically in the design repository. There are ways of navigating and collating objects that are useful for day to day development and build-time usage - this includes features out of the box and utilities constructed on top. There are a variety of techniques to navigate and find objects in the repository, the first 3 are out of the box, the 4th is an expert utility. Navigating by the tree, grouping by project and module - ok if you are aware of the exact module/folder that objects reside in. The structure panel is a useful way of finding parts of an object, especially when large rather than using the canvas. In large scale projects it helps to have accelerators (either find or collections below). Advanced find to search by name - 11gR2 included a find capability specifically for large scale projects. There were improvements in both the tree search and the object editors (including highlighting in mapping for example). So you can now do regular expression based search and quickly navigate to objects within a repository. Collections - logically organize your objects into virtual folders by shortcutting the actual objects. This is useful for a range of things since all the OWB services operate on collections too (export/import, validation, deployment). See the post here for new collection functionality in 11gR2. Reports for searching by type, updated on, updated by etc. Useful for activities such as periodic incremental actions (deploy all mappings changed in the past week). The report style view is useful since I can quickly see who changed what and when. You can see all the audit details for objects within each objects property inspector, but its useful to just get all objects changed today or example, all objects changed since my last build etc. This utility combines both UI extensions via experts and the public views on the repository. In the figure to the right you see the contextual option 'Object Search' which invokes the utility, you can see I have quite a number of modules within my project. Figure out all the potential objects which have been changed is not simple. The utility is an expert which provides this kind of search capability. The utility provides a report of the objects in the design repository which satisfy some filter criteria. The type of criteria includes; objects updated in the last n days optionally filter the objects updated by user filter the user by project and by type (table/mappings etc.) The search dialog appears with these options, you can multi-select the object types, so for example you can select TABLE and MAPPING. Its also possible to search across projects if need be. If you have multiple users using the repository you can define the OWB user name in the 'Updated by' property to restrict the report to just that user also. Finally there is a search name that will be used for some of the options such as building a collection - this name is used for the collection to be built. In the example I have done, I've just searched my project for all process flows and mappings that users have updated in the last 7 days. The results of the query are returned in a table containing the object names, types, full path and audit details. The columns are sort-able, you can sort the results by name, type, path etc. One of the cool things here, is that you can then perform operations on these objects - such as edit them, export single selection or entire results to MDL, create a collection from the results (now you have a saved set of references in the repository, you could do deploy/export etc.), create a deployment script from the results...or even add in your own ideas! You see from this that you can do bulk operations on sets of objects based on search results. So for example selecting the 'Build Collection' option creates a collection with all of the objects from my search, you can subsequently deploy/generate/maintain this collection of objects. Under the hood of the expert if just basic OMB commands from the product and the use of the public views on the design repository. You can see how easy it is to build up macro-like capabilities that will help you do day-to-day as well as build like tasks on sets of objects.

    Read the article

  • Case Class naming convention

    - by KChaloux
    In my recent adventures in Scala, I've found case classes to be a really nice alternative to enums when I need to include a bit of logic or several values with them. I often find myself writing structures that look like this, however: object Foo{ case class Foo(name: String, value: Int, other: Double) val BAR = Foo("bar", 1, 1.0) val BAZ = Foo("baz", 2, 1.5) val QUUX = Foo("quux", 3, 1.75) } I'm primarily worried here about the naming of the object and the case class. Since they're the same thing, I end up with Foo.Foo to get to the inner class. Would it be wise to name the case class something along the lines of FooCase instead? I'm not sure if the potential ambiguity might mess with the type system if I have to do anything with subtypes or inheritance.

    Read the article

  • null values vs "empty" singleton for optional fields

    - by Uko
    First of all I'm developing a parser for an XML-based format for 3D graphics called XGL. But this question can be applied to any situation when you have fields in your class that are optional i.e. the value of this field can be missing. As I was taking a Scala course on coursera there was an interesting pattern when you create an abstract class with all the methods you need and then create a normal fully functional subclass and an "empty" singleton subclass that always returns false for isEmpty method and throws exceptions for the other ones. So my question is: is it better to just assign null if the optional field's value is missing or make a hierarchy described above and assign it an empty singleton implementation?

    Read the article

  • Using an actor model versus a producer-consumer model?

    - by hewhocutsdown
    I'm doing some early-stage research towards architecting a new software application. Concurrency and multithreading will likely play a significant part, so I've been reading up on the various topics. The producer-consumer model, at least how it is expressed in Java, has some surface similarities but appears to be deeply dissimilar to the actor model in use with languages such as Erlang and Scala. I'm having trouble finding any good comparative data, or specific reasons to use or avoid the one or the other. Is the actor model even possible with Java or C#, or do you have do use one of the languages built for the purpose? Is there a third way?

    Read the article

  • Recommended book on Actors concurrency model (patterns, pitfalls, etc.)?

    - by Larry OBrien
    The Actors concurrency model is clearly gaining favor. Is there a good book that presents the patterns and pitfalls of the model? I am thinking about something that would discuss, for instance, the problems of consistency and correctness in the context of hundreds or thousands of independent Actors. It would be okay if it were associated with a specific language (erlang, I would imagine, since that seems universally regarded as the proven implementation of Actors), but I am hoping for something more than an introductory chapter or two. (FWIW, I'm actually most interested in Actors as they are implemented in Scala.)

    Read the article

  • Actor library / framework for C++

    - by Giorgio
    In the C++ project I am working for we would like to use something like Scala actors and remote actors (see e.g. this tutorial). Being able to use remote actors (actors living in different processes, possibly on different machines and communicating via TCP/IP) has higher priority for us because we have an application consisting of several processes deployed on different machines. Being able to use several actors living in the same process (possibly different threads) is also interesting, but has lower priority for the moment. On wikipedia I have found some links to actor libraries for C++ and I have started to look at Theron. Before I dive too deep into the details and build an extended example with Theron, I wanted to ask if anybody has experience with any of these libraries and which one they would recommend.

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 23 24 25 26 27 28 29 30 31 32 33 34  | Next Page >