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  • How can I check a type's dependents order to drop them and replace/modify the initial type?

    - by pctroll
    I tried to modify a type using the following code and it gave me the error code: 'ORA-02303'. I don't know much about Oracle or PL/SQL but I need to solve this; so I'd appreciate any further help with this. Thanks in advance. The code is just an example. But then again, I need to check its dependents first. create or replace type A as object ( x_ number, y_ varchar2(10), member procedure to_upper ); /

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  • Type patterns in Haskell

    - by finnsson
    I'm trying to compile a simple example of generic classes / type patterns (see http://www.haskell.org/ghc/docs/latest/html/users_guide/generic-classes.html) in Haskell but it won't compile. Any ideas about what's wrong with the code would be helpful. According to the documentation there should be a module Generics with the data types Unit, :*:, and :+: but ghc (6.12.1) complaints about Not in scope: data constructor 'Unit' etc. It seems like there's a package instant-generics with the data types :*:, :+: and U but when I import that module (instead of Generics) I get the error Illegal type pattern in the generic bindings {myPrint _ = ""} The complete source code is import Generics.Instant class MyPrint a where myPrint :: a -> String myPrint {| U |} _ = "" myPrint {| a :*: b |} (x :*: y) = "" (show x) ++ ":*:" ++ (show y) myPrint {| a :+: b |} _ = "" data Foo = Foo String instance MyPrint a => MyPrint a main = myPrint $ Foo "hi" and I compile it using ghc --make Foo.hs -fglasgow-exts -XGenerics -XUndecidableInstances P.S. The module Generics export no data types, only the functions: canDoGenerics mkGenericRhs mkTyConGenericBinds validGenericInstanceType validGenericMethodType

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  • what does driver program mean?

    - by Tom
    there is a quote from Algorithms for Java (sedgwick 2003) p. 135: "we commonly use driver programs when developing or debugging adt iplementations" what is meant by driver program? google just gives me loads of info about programming drivers, clearly not related

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  • Find the shortest path in a graph which visits certain nodes.

    - by dmd
    I have a undirected graph with about 100 nodes and about 200 edges. One node is labelled 'start', one is 'end', and there's about a dozen labelled 'mustpass'. I need to find the shortest path through this graph that starts at 'start', ends at 'end', and passes through all of the 'mustpass' nodes (in any order). ( http://3e.org/local/maize-graph.png / http://3e.org/local/maize-graph.dot.txt is the graph in question - it represents a corn maze in Lancaster, PA)

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  • Calculating Divergent Paths on Subtending Rings

    - by Russ
    I need to calculate two paths from A to B in the following graph, with the constraint that the paths can't share any edges: hmm, okay, can't post images, here's a link. All edges have positive weights; for this example I think we can assume that they're equal. My naive approach is to use Djikstra's algorithm to calculate the first path, shown in the second graph in the above image. Then I remove the edges from the graph and try to calculate the second path, which fails. Is there a variation of Djikstra, Bellman-Ford (or anything else) that will calculate the paths shown in the third diagram above? (Without special knowledge and removal of the subtending link, is what I mean)

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  • How Can I Reference Multiple Primary Keys For A Vector Type Primary Key

    - by AndreiC
    Hi, I have the following scenario: a table of projects and a table of persons, working on one or serveral projects. Also, I have a project id column (of type int), in the first table, which is a primary key there and I have a vector of project ids, as a column of type int, in my second table (persons), that references primary keys from the first table. What is the correct syntax for referencing multiple primary keys, from a vector foreign key. This is the way I am trying to create the table, but I am not sure what to place at the indicated line: CREATE TABLE Persons( Person_Id int, ..., ProjectsList int[], FOREIGN KEY (ProjectsList) REFERENCES Projects(Project_id) -- not sure what how to define the link here ); I hope my explanations are not over-complicated. Thank you in advance for helping!

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  • Type problem when including tuple

    - by Person
    I'm using Visual Studio 2008 with Feature Pack 1. I have a typedef like this typedef std::tr1::tuple<std::string, std::string, int> tileInfo with a function like this const tileInfo& GetTile( int x, int y ) const. In the implementation file the function has the exact same signature (with the added class name qualifier) and I am getting a redefinition: different type modifiers error. It seems to be looking for an int& instead of a tileInfo& When I mouse over the type of the function in the header, i.e. tileInfo& it brings up a little bar saying static const int tileInfo. I think this may be the problem, but I'm not sure what to do. Any help is appreciated, thanks.

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  • Changing an Action Type="click" to an auto action in SVG

    - by Dustin Myers
    I have a SVG document that I exported from Visio 2003 that would like to edit. This file has an action where you click a button it will navigate to a new screen. What I would like to do is have the navigation be based off of a data point rather than having to click the button. As an example I have a dynamic point data being brought into the SVG file and when that value changes from 0 to 1, I want this screen to automatically navigate to another screen. Below is the code I for clicking the button. <title content="structured text">Sheet.1107</title> <desc content="structured text">Button 1</desc> <v:custProps> <v:cp v:ask="false" v:langID="1033" v:invis="false" v:cal="0" v:val="VT4(Test Graphic 2)" v:type="0" v:prompt="" v:nameU="ObjRef" v:sortKey="" v:lbl="" v:format=""/> <v:cp v:ask="false" v:langID="1033" v:invis="false" v:cal="0" v:val="VT4(SF-S)" v:type="0" v:prompt="" v:nameU="DataPt" v:sortKey="" v:lbl="" v:format=""/> </v:custProps> <v:userDefs> <v:ud v:prompt="" v:nameU="NAVIGATE" v:val="VT4(NAVIGATE Test Graphic 2,&apos;&apos;,)"/> </v:userDefs> <v:textBlock v:margins="rect(4,4,4,4)"/> <v:textRect width="125.01" height="35" cx="62.5" cy="517.5"/> <rect x="0" width="125" y="500" height="35" class="st3"/> <text x="40.15" y="521.1" v:langID="1033" class="st4"><v:paragraph v:horizAlign="1"/><v:tabList/>Button 1</text> <jci:action type="click" count="1">if(evt.button == 0) nav(&apos;Test Graphic 2&apos;,&apos;&apos;,&apos;&apos;);</jci:action></g></a> In the above code I am bringing in the data value from SF-S. Once that value is equal to 1 I want this screen to automatically navigate to Test Graphic 2. I don't have any experience with coding so I am hoping someone here will be able to help me. Thanks, DMyers

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  • Are mathamatical Algorithms protected by copyright

    - by analogy
    I wish to implement an algorithm which i read in a journal paper in my software (commercial). I want to know if this is allowed or not. The algorithm in question is described in http://arxiv.org/abs/0709.2938 It is a very simple algorithm and a number of implementations exist in python (http://igraph.sourceforge.net/) and java. One of them is in gpl another which i got from a different researcher and had no license attached. There are significant differences in two implementations, e.g. second one uses threads and multiple cores. It is possible to rewrite/ (not translate) the algorithm. So can I use it in my software or on a server for commercial purpose. Thanks

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  • How to invoke a method with a generic return type using reflection

    - by Andre Luus
    Hi there! I'm trying to invoke a method with reflection that has a generic return type, like this: public class SomeClass<T> { public List<T> GetStuff(); } I get an instance of SomeClass with a call to a Repository's GetClass<T> generic method. MethodInfo lGetSomeClassMethodInfo = typeof(IRepository) .GetMethod("GetClass") .MakeGenericMethod(typeof(SomeClass<>); object lSomeClassInstance = lGetSomeClassMethodInfo.Invoke( lRepositoryInstance, null); After that, I this is where I try to invoke the GetStuff method: typeof(SomeClass<>).GetMethod("GetStuff").Invoke(lSomeClassInstance, null) I get an exception about the fact that the method has generic arguments. However, I can't use MakeGenericMethod to resolve the return type. Also, if instead of typeof(SomeClass<>) I use lSomeClassInstance.GetType() (which should have resolved types) GetMethod("GetStuff") returns null! UPDATE I have found the solution and will post the answer shortly.

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  • Select a data template by item type programatically in WPF

    - by Michael Stoll
    Hi all, unfortunately the WPF ToolbarTray does not support binding to a collection of ToolbarViewModels (Correct me, if I'm wrong). Thus I want to create the Toolbars programmatically. So there are two tasks, which I don't know how to do: Select the data template based on the item type. Instantiate the data template as toolbar Both should do the same as WPF does, when we use ItemsControl with an enumerable content and empty template. I used reflector to anaylse what WPF does. Task 1 is done by FrameworkElement.FindTemplateResourceInternal, but this is internal, and I couldn't find any public methods to acomplish the task. Of course one could enumerate all resources and match the data template data type property, but this seems sub-optimal. Who know's how to acomplish these tasks?

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  • Why state cannot be part of Presenter in MVP?

    - by rFactor
    I read http://www.codeproject.com/KB/architecture/MVC_MVP_MVVM_design.aspx and it said: As powerful as they are, both MVC and MVP have their problems. One of them is persistence of the View’s state. For instance, if the Model, being a domain object, does not know anything about the UI, and the View does not implement any business logic, then where would we store the state of the View’s elements such as selected items? Fowler comes up with a solution in the form of a Presentation Model pattern. I wonder why Presenter can't hold View state? It already holds all View logic. As far as I understand, in MVC and MVP the state is kept in View. In PM and MVVM the state is kept in the Presentation Model. Why can't Presenter follow PM in this particular case and contain the state of the view? Here is another article which says Presenter does not hold View state, instead the view does: http://www.codeproject.com/KB/aspnet/ArchitectureComparison.aspx

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  • Replace input type=file by an image

    - by nikospkrk
    Hi, Like a lot of people, I'd like to customize the ugly input type=file, and I know that it can't be done without some hacks and/or javascript. But, the thing is that in my case the upload file buttons are just for uploading images (jpeg|jpg|png|gif), so I was wondering if I could use a "clickable" image which would act exactly as an input type file (show the dialog box, and same $_FILE on submitted page). I found some workaround here, and this interesting one too (but does not work on Chrome =/). What do you guys do when you want to add some style to your file buttons? If you have any point of view about it, just hit the answer button ;) Cheers, Nicolas

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  • c# Reflection - Find the Generic Type of a Collection

    - by Andy Clarke
    Hi, I'm reflecting a property 'Blah' its Type is ICollection public ICollection<string> Blah { get; set; } private void button1_Click(object sender, RoutedEventArgs e) { var pi = GetType().GetProperty("Blah"); MessageBox.Show(pi.PropertyType.ToString()); } This gives me (as you'd expect!) ICollection<string> ... But really I want to get the collection type i.e. ICollection (rather than ICollection<string>) - does anyone know how i'd do this please?

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  • Visual Studio - easy way to bring up type definition as source code

    - by Igor Zevaka
    Oftentimes I want to bring up a system class in a source view, so that I can browse the properties and methods exposed by the class in a source view. Below is the screenshot of what I mean: Usually I do this by selecting the class name and pressing F12 (or right clickGo To Definition). However, if I haven't got it anywhere ready, i have type it up and then do Go To Definition. Most of the time I have to delete what I typed later on. Is there a way to bring up this view without having to type the class name? The VS2010 Navigate To dialog doesn't support this.

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  • Is it possible to set ContentType for a WCF WebGet method?

    - by James Cadd
    I'm working with a WCF restful/http method that returns a stream of image data. I want to make sure that the content type is marked as "image/png". The method is defined as: [ServiceContract] [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)] [ServiceBehavior(InstanceContextMode = InstanceContextMode.PerCall)] public class TileImageService { [WebGet(UriTemplate = "{id}")] public Stream GetTileImage(string id) { Bitmap bmp = new Bitmap(173, 173); Graphics g = Graphics.FromImage(bmp); g.Clear(Color.Blue); g.DrawString(DateTime.Now.ToLongTimeString(), new Font("Chiller", 20), Brushes.White, new PointF(10, 10)); g.Flush(); MemoryStream ms = new MemoryStream(); bmp.Save(ms, ImageFormat.Png); ms.Seek(0, SeekOrigin.Begin); return ms; } } In Firefox it looks like the content type is marked as application/octet stream. Is there a way to change the content type?

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  • Fitts Law, applying it to touch screens

    - by Caylem
    Been reading a lot into UI design lately and Fitts Law keeps popping up. Now from what i gather its basically the larger an item is, and the closer it is to your cursor, the easier it is to click on. So what about touch screen devices where the input comes from multiple touches or just single touches. What are the fundamentals to take into account considering this? Should it be something like, the hands of the user are on the sides of the device so the buttons should be close to the left and right hand sides of the device? Thanks

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  • Constructor type not found

    - by WaffleTop
    Hello, What I am doing: I am taking the Microsoft Enterprise Library 4.1 and attempting to expand upon it using a few derived classes. I have created a MyLogEntry, MyFormatter, and MyTraceListener which derive from their respective base classes when you remove the "My" from their names. What my problem is: Everything compiles fine. When I go to run a test using Logger.Write(logEntry) it errors right after it initializes MyTraceListener with an error message: "The current build operation (... EnterpriseLibrary.Logging.LogWriter, null]) failed: Constructor on type 'MyLogging.MyFormatter' not found. (Strategy type ConfiguredObjectStrategy, index 2) I figured it was something to do with the constructor so I tried removing it, add it, and adding a call to the base class LogFormatter. Nothing has worked. Does anyone have insight into this problem? Is it maybe a reference issue? Bad App.config configuration? Thank you in advance

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  • dose not name a type error in c++

    - by user985316
    #include <math.h> #include <stdlib.h> #include <stdio.h> #include <vector> #define IE 40 #define JE 40 #define KE 40 #define ia 7 #define ja 7 #define ka 7 #define NFREQS 3 using namespace std; main() float l,m,n,i,j,k,ic,jc,kc,nsteps,n_pml; float ddx,dt,T,epsz,muz,pi,eaf,npml; int ib,jb,kb; . . . . ic=IE*0.5 ; jc=JE*0.5 ; ....'ic'dose not name a type. ....'jc'dose not name a type.

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  • Unknown attribute xsi:type in XmlSerializer

    - by vanccoon
    I am learning XML Serialization and meet an issue, I have two claess [System.Xml.Serialization.XmlInclude(typeof(SubClass))] public class BaseClass { } public class SubClass : BaseClass { } I am trying to serialize a SubClass object into XML file, I use blow code XmlSerializer xs = new XmlSerializer(typeof(Base)); xs.Serialize(fs, SubClassObject); I noticed Serialization succeed, but the XML file is kind of like ... If I use XmlSerializer xs = new XmlSerializer(typeof(Base)); SubClassObject = xs.Deserialize(fs) as SubClass; I noticed it will complain xsi:type is unknown attribute(I registered an event), although all information embedded in the XML was parsed successfully and members in SubClassObject was restored correctly. Anyone has any idea why there is error in parsing xsi:type and anything I did wrong? Thanks

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  • Can an algorithmic process ever give true random numbers ?

    - by Arkapravo
    I have worked with random functions in python,ruby, MATLAB, Bash and Java. Nearly every programming language has a function to generate Random numbers. However, these apparently random sequences are termed as pseudo-random number sequences as the generation follows a deterministic approach, and the sequence seems to repeat (usually with a very large period). My question, can an algorithmic/programming process ever yield true random numbers ? The questions probably is more of theoretical computer science than just programming !

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  • saving a records containing a member of type string to a file (Delphi, Windows)

    - by wonderer
    I have a record that looks similar to: type TNote = record Title : string; Note : string; Index : integer; end; Simple. The reason I chose to set the variables as string (as opposed to an array of chars) is that I have no idea how long those strings are going to be. They can be 1 char long, 200 or 2000. Of course when I try to save the record to a type file (file of...) the compiler complains that I have to give a size to string. Is there a way to overcome this? or a way to save those records to an untyped file and still maintain a sort of searchable way? Please do not point me to possible solutions, if you know the solution please post code. Thank you

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  • Finding contained bordered regions from Excel imports.

    - by dmaruca
    I am importing massive amounts of data from Excel that have various table layouts. I have good enough table detection routines and merge cell handling, but I am running into a problem when it comes to dealing with borders. Namely performance. The bordered regions in some of these files have meaning. Data Setup: I am importing directly from Office Open XML using VB6 and MSXML. The data is parsed from the XML into a dictionary of cell data. This wonks wonderfully and is just as fast as using docmd.transferspreadsheet in Access, but returns much better results. Each cell contains a pointer to a style element which contains a pointer to a border element that defines the visibility and weight of each border (this is how the data is structured inside OpenXML, also). Challenge: What I'm trying to do is find every region that is enclosed inside borders, and create a list of cells that are inside that region. What I have done: I initially created a BFS(breadth first search) fill routine to find these areas. This works wonderfully and fast for "normal" sized spreadsheets, but gets way too slow for imports into the thousands of rows. One problem is that a border in Excel could be stored in the cell you are checking or the opposing border in the adjacent cell. That's ok, I can consolidate that data on import to reduce the number of checks needed. One thing I thought about doing is to create a separate graph that outlines the cells using the borders as my edges and using a graph algorithm to find regions that way, but I'm having trouble figuring out how to implement the algorithm. I've used Dijkstra in the past and thought I could do similar with this. So I can span out using no endpoint to search the entire graph, and if I encounter a closed node I know that I just found an enclosed region, but how can I know if the route I've found is the optimal one? I guess I could flag that to run a separate check for the found closed node to the previous node ignoring that one edge. This could work, but wouldn't be much better performance wise on dense graphs. Can anyone else suggest a better method? Thanks for taking the time to read this.

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