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• Visual Studio Macro: How to perform "File -> Save All" programatically

  - by Sean B

  I am looking for the equivalent of running "File - Save All" before certain Rake macros. What I have so far is: Private Sub Pre_Rake() Dim i As Integer DTE.Documents.SaveAll() For i = 1 To DTE.Solution.Projects.Count If Not DTE.Solution.Projects.Item(i).Saved Then DTE.Solution.Projects.Item(i).Save() End If Next End Sub DTE.Documents.SaveAll works fine, but the for loop does not save the project files as I would expect. If I make a copy of a file in the solution explorer, that file is not included in the project file (.CSPROJ) after Pre_Rake() runs. I would still have to press CTRL-SHIFT-S or File - Save All. So, how to Save All with a Visual Studio Macro?

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• Should I use implicit conversions to enforce preconditions?

  - by Malvolio

  It occurs to me that I could use use implicit conversions to both announce and enforce preconditions. Consider this: object NonNegativeDouble { implicit def int2nnd(d : Double) : NonNegativeDouble = new NonNegativeDouble(d) implicit def nnd2int(d : NonNegativeDouble) : Double = d.v def sqrt(n : NonNegativeDouble) : NonNegativeDouble = scala.math.sqrt(n) } class NonNegativeDouble(val v : Double ) { if (v < 0) { throw new IllegalArgumentException("negative value") } } object Test { def t1 = { val d : Double = NonNegativeDouble.sqrt(3.0); printf("%f\n", d); val n : Double = NonNegativeDouble.sqrt(-3.0); } } Ignore for the moment the actual vacuity of the example: my point is, the subclass NonNegativeDouble expresses the notion that a function only takes a subset of the entire range of the class's values. First is this: A good idea, a bad idea, or an obvious idea everybody else already knows about Second, this would be most useful with basic types, like Int and String. Those classes are final, of course, so is there a good way to not only use the restricted type in functions (that's what the second implicit is for) but also delegate to all methods on the underlying value (short of hand-implementing every delegation)?

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• How to avoid exceptions catches copy-paste in .NET

  - by Budda

  Working with .NET framework I have a service with a set of methods that can generates several types of exceptions: MyException2, MyExc1, Exception... To provide proper work for all methods, each of them contains following sections: void Method1(...) { try { ... required functionality } catch(MyException2 exc) { ... process exception of MyException2 type } catch(MyExc1 exc) { ... process exception of MyExc1 type } catch(Exception exc) { ... process exception of Exception type } ... process and return result if necessary } It is very boring to have exactly same stuff in EACH service method with exactly same exceptions processing functionality... Is there any possibility to "group" these catch-sections and use only one line (something similar to C++ macros)? Probably something new in .NET 4.0 is related to this topic? Thanks. P.S. Any thoughts are welcome.

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• How can I get Syslogging to work on the JVM?

  - by Synesso

  I want to do syslogging from Java. There is a log4j appender, but it doesn't seem to work (for me anyway ... though Google results show many others with this issue still unresolved). I'm trying to debug the appender, so I've written the following script based upon RFC3164 It runs, but no logging appears in the syslog. // scala import java.io._ import java.net._ val ds = new DatagramSocket() val fullMsg = "<11>May 26 14:47:22 Hello World" val packet = new DatagramPacket(fullMsg.getBytes("UTF-8"), fullMsg.length, InetAddress.getLocalHost, 514) ds send packet ds.close I also tried using /bin/nc, but it doesn't work either. echo "<14>May 26 15:23:83 Hello world" > nc -u localhost 514 The Ubuntu command /usr/bin/logger does work, however. logger -p user.info hello world # logs: May 26 15:25:10 dsupport2 jem: hello world What could I be doing wrong?

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• How do I write a scheme macro that defines a variable and also gets the name of that variable as a s

  - by Jason Baker

  This is mostly a follow-up to this question. I decided to just keep YAGNI in mind and created a global variable (libpython). I set it to #f initially, then set! it when init is called. I added a function that should handle checking if that value has been initialized: (define (get-cpyfunc name type) (lambda args (if libpython (apply (get-ffi-obj name libpython type) args) (error "Call init before using any Python C functions")))) So now here's what I want to do. I want to define a macro that will take the following: (define-cpyfunc Py_Initialize (_fun -> _void)) And convert it into this: (define Py_Initialize (get-cpyfunc "Py_Initialize" (_fun -> _void))) I've been reading through the macro documentation to try figuring this out, but I can't seem to figure out a way to make it work. Can anyone help me with this (or at least give me a general idea of what the macro would look like)? Or is there a way to do this without macros?

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• Constructor with non-instance variable assistant?

  - by Robert Fischer

  I have a number of classes that look like this: class Foo(val:BasicData) extends Bar(val) { val helper = new Helper(val) val derived1 = helper.getDerived1Value() val derived2 = helper.getDerived2Value() } ...except that I don't want to hold onto an instance of "helper" beyond the end of the constructor. In Java, I'd do something like this: public class Foo { final Derived derived1, derived2; public Foo(BasicData val) { Helper helper = new Helper(val); derived1 = helper.getDerived1Value(); derived2 = helper.getDerived2Value(); } } So how do I do something like that in Scala? I'm aware of creating a helper object of the same name of the class with an apply method: I was hoping for something slightly more succinct.

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• Running a method after the constructor of any derived class

  - by Alexey Romanov

  Let's say I have a Java class abstract class Base { abstract void init(); ... } and I know every derived class will have to call init() after it's constructed. I could, of course, simply call it in the derived classes' constructors: class Derived1 extends Base { Derived1() { ... init(); } } class Derived2 extends Base { Derived2() { ... init(); } } but this breaks "don't repeat yourself" principle rather badly (and there are going to be many subclasses of Base). Of course, the init() call can't go into the Base() constructor, since it would be executed too early. Any ideas how to bypass this problem? I would be quite happy to see a Scala solution, too.

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• How to expose a constructor variable(sic!) as read-only?

  - by Malax

  Hi StackOverflow! I have this rather simple question about Scala. Given that i have to following class definition: class Foo(var bar: Int) The code which is able to construct an instance of Foo must be able to pass the initial value for bar. But if I define bar as var the User is also able to change its value at runtime which is not what I want. The User should only be able to read bar. bar itself is modified internally so a val is not an option. I think I might be getting an answer very soon as this question is so simple. :-) Cheers, Malax

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• error: polymorphic expression with default arguments

  - by 0__

  This following bugs me: trait Foo[ A ] class Bar[ A ]( set: Set[ Foo[ A ]] = Set.empty ) This yields <console>:8: error: polymorphic expression cannot be instantiated to expected type; found : [A]scala.collection.immutable.Set[A] required: Set[Foo[?]] class Bar[ A ]( set: Set[ Foo[ A ]] = Set.empty ) ^ It is quite annoying that I have to repeat the type parameter in Set.empty. Why does the type inference fail with this default argument? The following works: class Bar[ A ]( set: Set[ Foo[ A ]] = { Set.empty: Set[ Foo[ A ]]}) Please note that this has nothing to do with Set in particular: case class Hallo[ A ]() class Bar[ A ]( hallo: Hallo[ A ] = Hallo.apply ) // nope Strangely not only this works: class Bar[ A ]( hallo: Hallo[ A ] = Hallo.apply[ A ]) ...but also this: class Bar[ A ]( hallo: Hallo[ A ] = Hallo() ) // ???

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• Is there a way to convert code to a string and vice versa in Python?

  - by Dragos Toader

  The original question was: Is there a way to declare macros in Python as they are declared in C: #define OBJWITHSIZE(_x) (sizeof _x)/(sizeof _x[0]) Here's what I'm trying to find out: Is there a way to avoid code duplication in Python? In one part of a program I'm writing, I have a function: def replaceProgramFilesPath(filenameBr): def getProgramFilesPath(): import os return os.environ.get("PROGRAMFILES") + chr(92) return filenameBr.replace("<ProgramFilesPath>",getProgramFilesPath() ) In another part, I've got this code embedded in a string that will later be output to a python file that will itself be run: """ def replaceProgramFilesPath(filenameBr): def getProgramFilesPath(): import os return os.environ.get("PROGRAMFILES") + chr(92) return filenameBr.replace("<ProgramFilesPath>",getProgramFilesPath() ) """ How can I build a "macro" that will avoid this duplication?

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• Adding Apache common dependency to Play Framework 2.0

  - by Mooh

  i want to import org.apache.commons.io but i'm getting this error: [info] Compiling 1 Java source to /home/ghost/Bureau/app/play-2.0.1/waf/target/scala-2.9.1/classes... [error] /home/ghost/Bureau/app/play-2.0.1/waf/app/controllers/Application.java:9: error: package org.apache.commons.io does not exist [error] import org.apache.commons.io.*; [error] ^ [error] /home/ghost/Bureau/app/play-2.0.1/waf/app/controllers/Application.java:41: error: cannot find symbol [error] FileUtils.copyFile(file, destinationFile); [error] ^ [error] symbol: variable FileUtils [error] location: class Application [error] 2 errors [error] {file:/home/ghost/Bureau/app/play-2.0.1/waf/}waf/compile:compile: javac returned nonzero exit code [error] application - Play can't find package org.apache.commons.io . How i can i add it as a dependency ?

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• how is a macro expanded in clojure?

  - by john wang

  In the book Programming Clojure(Stuart), when read how macros are expanded I got confused. user=> (defmacro chain ([x form] (list '. x form)) ([x form & more] (concat (list 'chain (list '. x form)) more))) #'user/chain The above macro can be expanded as: user=> (macroexpand '(chain a b c)) (. (. a b) c) But the following is only expanded to the first level: user=> (macroexpand '(and a b c)) (let* [and__3822__auto__ a] (if and__3822__auto__ (clojure.core/and b c) and__3822__auto__)) The and macro source: user=> (source and) (defmacro and([] true) ([x] x) ([x & next] `(let [and# ~x] (if and# (and ~@next) and#)))) Why is the chain macro expanded all the way but the and not ? Why is it not expanded to something like the following: user=> (macroexpand '(chain a b c d)) (. (chain a b c) d)

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• powerpoint macro timer

  - by mustafabattal

  Hi, I have to complete a timer on powerpoint, it countsdown for a specificed amount of time when a shape on particular slide is clicked. I heard macros could be a way to do this, but I have very little knowledge about them. With my research I was able to add a macro and pop out a message box when a shape is clicked*. How can I implement a timer with this? VB syntax is pretty unfamiliar to me. What happens after timer finishes is another question though. *with macro in module: sub hello_world() MsgBox( 'hello world!') end sub

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• Possible to not use ID field but another column name? in Lift

  - by bstevens90

  I am connected to a oracle database from a scala/lift webapp. I have been able to successfully pull information from the database as I wished but am having one issue. For each table I want to access I am required to add an ID field so that the app will work with the trait IdPK. What mapper class or trait can I use to override this? I have been trying to find one but been unable to locate it. Figured people have not always had an ID field on every table they make that is just called ID... class DN_REC extends LongKeyedMapper[DN_REC] with IdPK { def getSingleton = DN_REC object dn_rec_id extends MappedInt(this){ } This is what I am talking about. I would like to use the dn_rec_id as my primary key as it is on the table. Thanks

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• GAE JCache NumberFormatException, will I need to write Java to avoid?

  - by Jasper

  This code below produces a NumberFormatException in this line: val cache = cf.createCache(Collections.emptyMap()) Do you see any errors? Will I need to write a Java version to avoid this, or is there a Scala way? ... import java.util.Collections import net.sf.jsr107cache._ object QueryGenerator extends ServerResource { private val log = Logger.getLogger(classOf[QueryGenerator].getName) } class QueryGenerator extends ServerResource { def getCounter(cache:Cache):long = { if (cache.containsKey("counter")) { cache.get("counter").asInstanceOf[long] } else { 0l } } @Get("html") def getHtml(): Representation = { val cf = CacheManager.getInstance().getCacheFactory() val cache = cf.createCache(Collections.emptyMap()) val counter = getCounter(cache) cache.put("counter", counter + 1) val q = QueueFactory.getQueue("query-generator") q.add(TaskOptions.Builder.url("/tasks/query-generator").method(Method.GET).countdownMillis(1000L)) QueryGenerator.log.warning(counter.toString) new StringRepresentation("QueryGenerator started!", MediaType.TEXT_HTML) } } Thanks!

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• Setting cookie in LiftFilter

  - by Gero

  Hi, How do I set a cookie in a LiftFilter.doFilter method? I tried to set the cookie as follows (stripped some code): class AuthenticationFilter extends LiftFilter { override def doFilter(request: ServletRequest, response: ServletResponse , chain: FilterChain) { val cookie = new HTTPCookie("SomeCookie", Full("" + System.nanoTime), Empty, Full("/authentication"), Full(60 * 60 * 24 * 14), Empty, Empty) cookie.setPath("/somePath") S.addCookie(cookie) val httpResp = response.asInstanceOf[HttpServletResponse] httpResp.sendRedirect("/some/page.html") } } However, when I check the browsers cookie, no cookie is set (apart from JSESSIONID), and I know the doFilter method is being executed because of logging messages and the fact that the browser is redirected to /some/page.html. I'm using Scala 2.8, Lift 2.1-SNAPSHOT and the app is running is GAE (1.3.6, only tested on dev_appserver so far). Any ideas? Thanks, Gero

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• is the + in += on a Map a prefix operator of =?

  - by Steve

  In the book "Programming in Scala" from Martin Odersky there is a simple example in the first chapter: var capital = Map("US" -> "Washington", "France" -> "Paris") capital += ("Japan" -> "Tokyo") The second line can also be written as capital = capital + ("Japan" -> "Tokyo") I am curious about the += notation. In the class Map, I didn't found a += method. I was able to the same behaviour in an own example like class Foo() { def +(value:String) = { println(value) this } } object Main { def main(args: Array[String]) = { var foo = new Foo() foo = foo + "bar" foo += "bar" } } I am questioning myself, why the += notation is possible. It doesn't work if the method in the class Foo is called test for example. This lead me to the prefix notation. Is the + a prefix notation for the assignment sign (=)? Can somebody explain this behaviour?

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• How to make the first invocation of a macro different from all the next ones ?

  - by LB

  Hi, that may be really simple but i'm unable to find a good answer. How can I make a macro representing first a certain value and then a different one ? I know that's nasty but i need it to implicitly declare a variable the first time and then do nothing. This variable is required by other macros that i'm implementing. Should i leverage "argument prescan" ? thanks for the answers. EDIT To make things clearer. Suppose i have a macro FOO, and I do something like FOO FOO FOO I would like the result to be foo bar bar I don't want the actual code to be cluttered by ifndef. The programmer should only have to write macro invocations.

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• What is the purpose of AnyVal?

  - by DaoWen

  I can't think of any situation where the type AnyVal would be useful, especially with the addition of the Numeric type for abstracting over Int, Long, etc. Are there any actual use cases for AnyVal, or is it just an artifact that makes the type hierarchy a bit prettier? Just to clarify, I know what AnyVal is, I just can't think of any time that I would actually need it in Scala. When would I ever need a type that encompassed Int, Character and Double? It seems like it's just there to make the type hierarchy prettier (i.e. it looks nicer to have AnyVal and AnyRef as siblings rather than having Int, Character, etc. inherit directly from Any).

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• Create macro to move data in a column UP?

  - by user1786695

  I have an excel sheet of which the data was jumbled: for example, the data that should have been in Columns AB and AC were instead in Columns B and C, but on the row after. I have the following written which moved the data from B and C to AB and AC respectively: Dim rCell As Range Dim rRng As Range Set rRng = Sheet1.Range("A:A") i = 1 lastRow = ActiveSheet.Cells(Rows.Count, "A").End(xlUp).Row For Each rCell In rRng.Cells If rCell.Value = "" Then Range("AB" & i) = rCell.Offset(0, 1).Value rCell.Offset(0, 1).ClearContents End If i = i + 1 If i = lastRow + 1 Then Exit Sub End If Next rCell End Sub However, it doesn't fix the problem of the data being on the row BELOW the appropriate row now that they are in the right columns. I am new to VBA Macros so I would appreciate any help to make the data now align. I tried toggling the Offset parameter (-1,0) but it's not working.

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• Generics not so generic !!

  - by Aymen

  Hi I tried to implement a generic binary search algorithm in scala. Here it is : type Ord ={ def <(x:Any):Boolean def >(x:Any):Boolean } def binSearch[T <: Ord ](x:T,start:Int,end:Int,t:Array[T]):Boolean = { if (start > end) return false val pos = (start + end ) / 2 if(t(pos)==x) true else if (t(pos) < x) binSearch(x,pos+1,end,t) else binSearch(x,start,pos-1,t) } everything is OK until I tried to actually use it (xD) : binSearch(3,0,4,Array(1,2,5,6)) the compiler is pretending that Int not a member of Ord, well what shall I do to solve this ? Thanks

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• What are common anti-patterns when using VBA

  - by Ahmad

  I have being coding a lot in VBA lately (maintenance and new code), specifically with regards to Excel automation etc. = macros. Typically most of this has revolved around copy/paste, send some emails, import some files etc. but eventually just ends up as a Big ball of mud As a person who values clean code, I find it very difficult to produce 'decent' code when using VBA. I think that in most cases, this is a direct result of the macro-recorder. Very helpful to get you started, but most times, there are one too many lines of code that achieve the end result. Edit: The code from the macro-recorder is used as a base to get started, but is not used in its entirety in the end result I have already created a common addin that has my commonly used subroutines and some utility classes in an early attempt to enforce some DRYness - so this I think is a step in the right direction. But I feel as if it's a constant square peg, round hole situation. The wiki has an extensive list of common anti-patterns and what scared me the most was how many I have implemented in one way or another. The question Now considering, that my mindset is OO design, what some common anti-patterns and the possible solutions when designing a solution (think of this - how would designing a solution using Excel and VBA be different from say a .net/java/php/.../ etc solution) ; and when doing common tasks like copying data, emailing, data importing, file operations... etc An anti-pattern as defined by Wikipedia is: In software engineering, an anti-pattern (or antipattern) is a pattern that may be commonly used but is ineffective and/or counterproductive in practice

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• JVM segmentation faults due to "Invalid memory access of location"

  - by Dan

  I have a small project written in Scala 2.9.2 with unit tests written using ScalaTest. I use SBT for compiling and running my tests. Running sbt test on my project makes the JVM segfault regularly, but just compiling and running my project from SBT works fine. Here is the exact error message: Invalid memory access of location 0x8 rip=0x10959f3c9 [1] 11925 segmentation fault sbt I cannot locate a core dump anywhere, but would be happy to provide it if it can be obtained. Running java -version results in this: java version "1.6.0_37" Java(TM) SE Runtime Environment (build 1.6.0_37-b06-434-11M3909) Java HotSpot(TM) 64-Bit Server VM (build 20.12-b01-434, mixed mode) But I've also got Java 7 installed (though I was never able to actually run a Java program with it, afaik). Another issue that may be related: some of my test cases contain titles including parentheses like ( and ). SBT or ScalaTest (not sure) will consequently insert square parens in the middle of the output. For example, a test case with the name (..)..(..) might suddenly look like (..[)..](..). Any help resolving these issues is much appreciated :-) EDIT: I installed the Java 7 JDK, so now java -version shows the right thing: java version "1.7.0_07" Java(TM) SE Runtime Environment (build 1.7.0_07-b10) Java HotSpot(TM) 64-Bit Server VM (build 23.3-b01, mixed mode) This also means that I now get a more detailed segfault error and a core dump: # # A fatal error has been detected by the Java Runtime Environment: # # SIGSEGV (0xb) at pc=0x000000010a71a3e3, pid=16830, tid=19459 # # JRE version: 7.0_07-b10 # Java VM: Java HotSpot(TM) 64-Bit Server VM (23.3-b01 mixed mode bsd-amd64 compressed oops) # Problematic frame: # V [libjvm.dylib+0x3cd3e3] And the dump.

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• Does isEmpty method in Stream evaluate the whole Stream?

  - by abhin4v

  In Scala, does calling isEmtpy method on an instance of Stream class cause the stream to be evaluated completely? My code is like this: import Stream.cons private val odds: Stream[Int] = cons(3, odds.map(_ + 2)) private val primes: Stream[Int] = cons(2, odds filter isPrime) private def isPrime(n: Int): Boolean = n match { case 1 => false case 2 => true case 3 => true case 5 => true case 7 => true case x if n % 3 == 0 => false case x if n % 5 == 0 => false case x if n % 7 == 0 => false case x if (x + 1) % 6 == 0 || (x - 1) % 6 == 0 => true case x => primeDivisors(x) isEmpty } import Math.{sqrt, ceil} private def primeDivisors(n: Int) = primes takeWhile { _ <= ceil(sqrt(n))} filter {n % _ == 0 } So, does the call to isEmpty on the line case x => primeDivisors(x) isEmpty cause all the prime divisors to be evaluated or only the first one?

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• How can I make this method more Scalalicious

  - by Neil Chambers

  I have a function that calculates the left and right node values for some collection of treeNodes given a simple node.id, node.parentId association. It's very simple and works well enough...but, well, I am wondering if there is a more idiomatic approach. Specifically is there a way to track the left/right values without using some externally tracked value but still keep the tasty recursion. /* * A tree node */ case class TreeNode(val id:String, val parentId: String){ var left: Int = 0 var right: Int = 0 } /* * a method to compute the left/right node values */ def walktree(node: TreeNode) = { /* * increment state for the inner function */ var c = 0 /* * A method to set the increment state */ def increment = { c+=1; c } // poo /* * the tasty inner method * treeNodes is a List[TreeNode] */ def walk(node: TreeNode): Unit = { node.left = increment /* * recurse on all direct descendants */ treeNodes filter( _.parentId == node.id) foreach (walk(_)) node.right = increment } walk(node) } walktree(someRootNode) Edit - The list of nodes is taken from a database. Pulling the nodes into a proper tree would take too much time. I am pulling a flat list into memory and all I have is an association via node id's as pertains to parents and children. Adding left/right node values allows me to get a snapshop of all children (and childrens children) with a single SQL query. The calculation needs to run very quickly in order to maintain data integrity should parent-child associations change (which they do very frequently). In addition to using the awesome Scala collections I've also boosted speed by using parallel processing for some pre/post filtering on the tree nodes. I wanted to find a more idiomatic way of tracking the left/right node values. After looking at the answers listed I have settled on this synthesised version: def walktree(node: TreeNode) = { def walk(node: TreeNode, counter: Int): Int = { node.left = counter node.right = treeNodes .filter( _.parentId == node.id) .foldLeft(counter+1) { (counter, curnode) => walk(curnode, counter) + 1 } node.right } walk(node,1) }

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