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  • Reusing named_scope to define another named_scope

    - by Sergei Kozlov
    The problem essence as I see it One day, if I'm not mistaken, I have seen an example of reusing a named_scope to define another named_scope. Something like this (can't remember the exact syntax, but that's exactly my question): named_scope :billable, :conditions => ... named_scope :billable_by_tom, :conditions => { :billable => true, :user => User.find_by_name('Tom') } The question is: what is the exact syntax, if it's possible at all? I can't find it back, and Google was of no help either. Some explanations Why I actually want it, is that I'm using Searchlogic to define a complex search, which can result in an expression like this: Card.user_group_managers_salary_greater_than(100) But it's too long to be put everywhere. Because, as far as I know, Searchlogic simply defines named_scopes on the fly, I would like to set a named_scope on the Card class like this: named_scope from_big_guys, { user_group_managers_salary_greater_than(100) } - this is where I would use that long Searchlogic method inside my named_scope. But, again, what would be the syntax? Can't figure it out. Resume So, is named_scope nesting (and I do not mean chaining) actually possible?

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  • Pre Project Documentation

    - by DeanMc
    I have an issue that I feel many programmers can relate to... I have worked on many small scale projects. After my initial paper brain storm I tend to start coding. What I come up with is usually a rough working model of the actual application. I design in a disconnected fashion so I am talking about underlying code libraries, user interfaces are the last thing as the library usually dictates what is needed in the UI. As my projects get bigger I worry that so should my "spec" or design document. The above paragraph, from my investigations, is echoed all across the internet in one fashion or another. When a UI is concerned there is a bit more information but it is UI specific and does not relate to code libraries. What I am beginning to realise is that maybe code is code is code. It seems from my extensive research that there is no 1:1 mapping between a design document and the code. When I need to research a topic I dump information into OneNote and from there I prioritise features into versions and then into related chunks so that development runs in a fairly linear fashion, my tasks tend to look like so: Implement Binary File Reader Implement Binary File Writer Create Object to encapsulate Data for expression to the caller Now any programmer worth his salt is aware that between those three to do items could be a potential wall of code that could expand out to multiple files. I have tried to map the complete code process for each task but I simply don't think it can be done effectively. By the time one mangles pseudo code it is essentially code anyway so the time investment is negated. So my question is this: Am I right in assuming that the best documentation is the code itself. We are all in agreement that a high level overview is needed. How high should this be? Do you design to statement, class or concept level? What works for you?

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  • Progressbar behaves strangely

    - by wanderameise
    I just created an application in C# that uses a thread which polls the UART for a receive event. If data is received an event is triggered in my main thread (GUI) and a progress bar is controlled via PerformStep() method (of course, I previously set the Max value accordingly). PerformStep is invoked using the following expression to handle cross threading this.Invoke((Action)delegate{progressBar2.PerformStep();}) When running this application the progressbar never hits its final value. It stops at 80%. When debugging and stopping at the line mentioned above, everything works fine using single steps. I have no idea what is going one! Start read thread on main thread: pThreadWrite = new Thread(new ThreadStart(ReadThread)); pThreadWrite.Start(); Read Thread: private void ReadThread() { while(1) { if (ReceiveEvent) { FlashProgressBar(); } } } Event that is triggered in main thread: private void FlashProgressBar() { this.Invoke((Action)delegate { progressBar2.PerformStep();}); } (It's a simplified representation of my code) It seems as if the internal progress is faster than the visual one.

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  • How to remove words based on a word count

    - by Chris
    Here is what I'm trying to accomplish. I have an object coming back from the database with a string description. This description can be up to 1000 characters long, but we only want to display a short view of this. So I coded up the following, but I'm having trouble in actually removing the number of words after the regular expression finds the total count of words. Does anyone have good way of dispalying the words which are less than the Regex.Matches? Thanks! if (!string.IsNullOrEmpty(myObject.Description)) { string original = myObject.Description; MatchCollection wordColl = Regex.Matches(original, @"[\S]+"); if (wordColl.Count < 70) // 70 words? { uxDescriptionDisplay.Text = string.Format("<p>{0}</p>", myObject.Description); } else { string shortendText = original.Remove(200); // 200 characters? uxDescriptionDisplay.Text = string.Format("<p>{0}</p>", shortendText); } }

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  • Find window with specific text for a Process

    - by Axarydax
    Hello, I'm trying to find if a window with specific has been open by a Process. That process spawns multiple windows, and I need to check them all. I have no trouble finding the process, with foreach (Process p in Process.GetProcesses()) { if (p.MainModule.FileName.ToLower().EndsWith("foo.exe")) FindChildWindowWithText(p); //do work the problem is what to do next. I cannot use Process' MainWindowText, because it changes with whichever window is activated. Then I've tried to use Windows function EnumChildWindows and GetWindowText, but I am not sure if I'm passing a correct handle to EnumChildWindows. The EnumChildWindows works as expected when passed MainWindowHandle, but of course the MainWindowHandle changes with active window. So I passed Process.Handle, but I get different handles and different results when switching the app's windows. (I understand that EnumChildWindows returns handles to not only windows, but controls in .net speak, that's no problem if I could get the caption of the window too) Maybe I am doing this the wrong way and I need a different approach - again, my problem is as simple as finding a window with text that matches specific regular expression. So I would probably need a function that enumerates all windows, that are visible in the taskbar or so. Thanks

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  • Alter a function as a parameter before evaluating it in R?

    - by Shane
    Is there any way, given a function passed as a parameter, to alter its input parameter string before evaluating it? Here's pseudo-code for what I'm hoping to achieve: test.func <- function(a, b) { # here I want to alter the b expression before evaluating it: b(..., val1=a) } Given the function call passed to b, I want to add in a as another parameter without needing to always specify ... in the b call. So the output from this test.func call should be: test.func(a="a", b=paste(1, 2)) "1" "2" "a" Edit: Another way I could see doing something like this would be if I could assign the additional parameter within the scope of the parent function (again, as pseudo-code); in this case a would be within the scope of t1 and hence t2, but not globally assigned: t2 <- function(...) { paste(a=a, ...) } t1 <- function(a, b) { local( { a <<- a; b } ) } t1(a="a", b=t2(1, 2)) This is somewhat akin to currying in that I'm nesting the parameter within the function itself. Edit 2: Just to add one more comment to this: I realize that one related approach could be to use "prototype-based programming" such that things would be inherited (which could be achieved with the proto package). But I was hoping for a easier way to simply alter the input parameters before evaluating in R.

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  • When is a bool not a bool (compiler warning C4800)

    - by omatai
    Consider this being compiled in MS Visual Studio 2005 (and probably others): CPoint point1( 1, 2 ); CPoint point2( 3, 4 ); const bool point1And2Identical( point1 == point2 ); // C4800 warning const bool point1And2TheSame( ( point1 == point2 ) == TRUE ); // no warning What the...? Is the MSVC compiler brain-dead? As far as I can tell, TRUE is #defined as 1, without any type information. So by what magic is there any difference between these two lines? Surely the type of the expression inside the brackets is the same in both cases? [This part of the question now satisfactorily answered in the comments just below] Personally, I think that avoiding the warning by using the == TRUE option is ugly (though less ugly than the != 0 alternative, despite being more strictly correct), and it is better to use #pragma warning( disable:4800 ) to imply "my code is good, the compiler is an ass". Agree? Note - I have seen all manner of discussion on C4800 talking about assigning ints to bools, or casting a burger combo with large fries (hold the onions) to a bool, and wondering why there are strange results. I can't find a clear answer on what seems like a much simpler question... that might just shine line on C4800 in general.

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  • Match Anything Except a Sub-pattern

    - by Tim Lytle
    I'd like to accomplish what this (invalid I believe) regular expression tries to do: <p><a>([^(<\/a>)]+?)<\/a></p>uniquestring Essentially match anything except a closing anchor tag. Simple non-greedy doesn't help here because `uniquestring' may very well be after another distant closing anchor tag: <p><a>text I don't <tag>want</tag> to match</a></p>random data<p><a>text I do <tag>want to</tag> match</a></p>uniquestring more matches <p><a>of <tag>text I do</tag> want to match</a></p>uniquestring So I have more tag in between the anchor tags. And I'm using the presence of uniquestring to determine if I want to match the data. So a simple non-greedy ends up matching everything from the start of the data I don't want to the end of the data I do want. I know I'm edging close to the problems regular expressions (or at least my knowledge of them) aren't good at solving. I could just through the data at an HTML/XML parser, but it is just one simple(ish) search. Is there some easy way to do this that I'm just missing?

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  • Doesn't (didn't) Scala have automatically generated setters?

    - by Malvolio
    Google and my failing memory are both giving me hints that it does, but every attempt is coming up dry. class Y { var y = 0 } var m = new Y() m.y_(3) error: value y_ is not a member of Y Please tell me I am doing something wrong. (Also: please tell me what it is I am doing wrong.) EDIT The thing I am not doing wrong, or at least not the only thing I am doing wrong, is the way I am invoking the setter. The following things also fail, all with the same error message: m.y_ // should be a function valued expression m.y_ = (3) // suggested by Google and by Mchl f(m.y_) // where f takes Int => Unit as an argument f(m.y) // complains that I am passing in Int not a function I am doing this all through SimplyScala, because I'm too lazy and impatient to set up Scala on my tiny home machine. Hope it isn't that... And the winner is ... Fabian, who pointed out that I can't have a space between the _ and the =. I thought out why this should be and then it occurred to me: The name of the setter for y is not y_, it is y_= ! Observe: class Y { var y = 0 } var m = new Y() m.y_=(3) m.y res1: Int = 3 m.y_= error: missing arguments for method y_= in class Y; follow this method with `_` if you want to treat it as a partially applied function m.y_= ^ m.y_=_ res2: (Int) => Unit = def four(f : Int => Unit) = f(4) four(m.y_=) m.y res3: Int = 4 Another successful day on StackExchange.

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  • CodeModel help needed for right-hand singleton.getinstance() assignment.

    - by antarti
    I've been able to generate 99% of what I need with the CodeModel API, but I am stumped here... Using the various "directXX" methods does not add import statements to the generated code, and I can work without the "directXXX" type of methods except for one place in a generated class. Suppose I desire a generated method like: /** * Copies data from this Value-Obj instance, to the returned PERSON instance. * * @return PERSON * */ public PERSON mapVOToPERSON() throws MappingException { Mapper mapper = (com.blah.util.MapperSingleton.getMapperInstance()); return mapper.map(this, PERSON.class); } You can see the right hand of the Mapper assignment in parens. Emitting the entire package+class was the only way I could find to just declare "SomeSingleton.someMethod()" on the right hand side and have the generated code compile. Without the MapperSingleton being added to the object model, there is no import generated... Questions: 1) Is there a way to force an import to be generated? 2) How to declare an expression that gives me the right side of the Mapper assignment within the object model (so that an import of MapperSingleton gets generated. Any help appreciated...

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  • How do I define a monadic function to work on a list in J?

    - by Gregory Higley
    Let's say I have the following J expression: # 3 ((|=0:)#]) 1+i.1000 This counts the number of numbers between 1 and 1000 that are evenly divisible by 3. (Now, before anyone points out that there's an easier way to do this, this question is about the syntax of J, and not mathematics.) Let's say I define a monadic function for this, as follows: f =: monad define # y ((|=0:)#]) 1+i.1000 ) This works great with a single argument, e.g., f 4 250 If I pass a list in, I get a length error: f 1 2 3 |length error: f Now, I completely understand why I get the length error. When you substitute the list 1 2 3 for the y argument of the monad, you get: # 1 2 3 ((|=0:)#]) 1+i.1000 If you know anything about J, it's pretty clear why the length error is occurring. So, I don't need an explanation of that. I want to define the function such that when I pass a list, it returns a list, e.g., f 1 2 3 1000 500 333 How can I either (a) redefine this function to take a list and return a list or (b) get the function to work on a list as-is without being redefined, perhaps using some adverb or other technique?

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  • how do i make the app take correct input..?

    - by user1824343
    This is my windows app's one layout which converts Celsius to Fahrenheit. The problem is that when I try to input the temperature it shows some junk(for eg: if i enter '3' it displayin '3.0000009') and sometimes its even showing stack overflow exception. The output is also not shown properly : cel.text is the textbox for celsius. fahre.text is the textbox for fahrenheit. namespace PanoramaApp1 { public partial class FahretoCel : PhoneApplicationPage { public FahretoCel() { InitializeComponent(); } private void fahre_TextChanged(object sender, TextChangedEventArgs e) { if (fahre.Text != "") { try { double F = Convert.ToDouble(fahre.Text); cel.Text = "" + ((5.0/9.0) * (F - 32)) ; //this is conversion expression } catch (FormatException) { fahre.Text = ""; cel.Text = ""; } } else { cel.Text = ""; } } private void cel_TextChanged(object sender, TextChangedEventArgs e) { if (cel.Text != "") { try { Double c = Convert.ToDouble(cel.Text); fahre.Text = "" + ((c *(9.0 / 5.0 )) + 32); } catch (FormatException) { fahre.Text = ""; cel.Text = ""; } } else { fahre.Text = ""; } } } }

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  • find, excluding dir, not descending into dir, AND using maxdepth and mindepth

    - by user1680819
    This is RHEL 5.6 and GNU find 4.2.27. I am trying to exclude a directory from find, and want to make sure that directory isn't descended into. I've seen plenty of posts saying -prune will do this - and it does. I can run this command: find . -type d -name "./.snapshot*" -prune -o -print and it works. I run it through strace and verify it is NOT descending into .snapshot. I also want to find directories ONLY at a certain level. I can use mindepth and maxdepth to do this: find . -maxdepth 8 -mindepth 8 -type d and it gives me all the dirs 8 levels down, including what's in .snapshot. If I combine the prune and mindepth and maxdepth options: find . -maxdepth 8 -mindepth 8 -type d \( -path "./.snapshot/*" -prune -o -print \) the output is right - I see all the dirs 8 levels down except for what's in .snapshot, but if I run that find through strace, I see that .snapshot is still being descended into - to levels 1 through 8. I've tried a variety of different combinations, moving the precedence parens around, reording expression components - everything that yields the right output still descends into .snapshot. I see in the man page that -prune doesn't work with -depth, but doesn't say anything about mindepth and maxdepth. Can anyone offer any advice? Thanks... Bill

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  • C# code simple console program not working

    - by Wast334
    I am trying to test some console ability in C#.. I can't get this code to work using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace ConsoleApplication1 { class Program { static void Main(string[] args) { Dim myMessage; myMessage = @"Hello World"; printf(@"%@", myMessage); return 0; } } } I am getting a bunch of compiler errors i am not sure what I am doing wrong..? Error 1 The type or namespace name 'Dim' could not be found (are you missing a using directive or an assembly reference?) C:\Documents and Settings\wstevens\Local Settings\Application Data\Temporary Projects\ConsoleApplication1\Program.cs 12 13 ConsoleApplication1 Error 2 The name 'printf' does not exist in the current context C:\Documents and Settings\wstevens\Local Settings\Application Data\Temporary Projects\ConsoleApplication1\Program.cs 14 13 ConsoleApplication1 Error 3 Since 'ConsoleApplication1.Program.Main(string[])' returns void, a return keyword must not be followed by an object expression C:\Documents and Settings\wstevens\Local Settings\Application Data\Temporary Projects\ConsoleApplication1\Program.cs 15 13 ConsoleApplication1

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  • help date format in vb.net

    - by bachchan
    Dim Con As OleDb.OleDbConnection Dim Sql As String = Nothing Dim Reader As OleDb.OleDbDataReader Dim ComboRow As Integer = -1 Dim Columns As Integer = 0 Dim Category As String = Nothing Dim oDatumMin As Date Dim column As String column = Replace(TxtDateMax.Text, "'", "''") 'oDatumMin = Convert.ToDateTime(TxtDateMin.Text) oDatumMin = DtpMin.Value Dim oPath As String oPath = Application.StartupPath ' Select records. Con = New OleDb.OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" & oPath & "\trb.accdb;") Dim cmd As New OleDb.OleDbCommand 'Dim data_reader As OleDbDataReader = cmd.ExecuteReader() Sql = ("SELECT * FROM " & cmbvalue & " WHERE Datum>='" & oDatumMin & "'") cmd = New OleDb.OleDbCommand(Sql, Con) Con.Open() Reader = cmd.ExecuteReader() Do While Reader.Read() Dim new_item As New ListViewItem(Reader.Item("Datum").ToString) new_item.SubItems.Add(Reader.Item("Steleks i krpe za cišcenje-toal papir-ubrusi-domestos").ToString) new_item.SubItems.Add(Reader.Item("TEKUCINA ZA CIŠCENJE PLOCICA").ToString) new_item.SubItems.Add(Reader.Item("KESE ZA SMECE").ToString) new_item.SubItems.Add(Reader.Item("OSTALO-džoger-spužva za laminat").ToString) new_item.SubItems.Add(Reader.Item("PAPIR").ToString) LvIzvjestaj.Items.Add(new_item) Loop ' Close the connection.strong text Con.Close()`` when i select table,(cmbvalue) from combobox and when i select date from datetime picker (dtp) or in last case from texbox converted to date and time sql looks like this "SELECT * FROM Uprava WHERE Datum='2.6.2010 10:28:14'" and all query looks ok but am geting Data type mismatch in criteria expression. error for date (oDatumMin) when excute column in access is also set to date i have no idea what else to try

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  • Extract information from a Func<bool, T> or alike lambda

    - by Syska
    I''m trying to build a generic cache layer. ICacheRepository Say I have the following: public class Person { public int PersonId { get; set; } public string Firstname { get; set; } public string Lastname { get; set; } public DateTime Added { get; set; } } And I have something like this: list.Where(x => x.Firstname == "Syska"); Here I want to extract the above information, to see if the query supplied the "PersonId" which it did not, so I dont want to cache it. But lets say I run a query like this: list.Where(x => x.PersonId == 10); Since PersonId is my key ... I want to cache it. with the key like "Person_10" and I later can fetch it from the cache. I know its possible to extract the information with Expression<Func<>> but there seems to be a big overhead of doing this (when running compile and extract the Constant values etc. and a bunch of cache to be sure to parse right) Are there a framework for this? Or some smart/golden way of doing this ?

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  • How does Haskell do pattern matching without us defining an Eq on our data types?

    - by devoured elysium
    I have defined a binary tree: data Tree = Null | Node Tree Int Tree and have implemented a function that'll yield the sum of the values of all its nodes: sumOfValues :: Tree -> Int sumOfValues Null = 0 sumOfValues (Node Null v Null) = v sumOfValues (Node Null v t2) = v + (sumOfValues t2) sumOfValues (Node t1 v Null) = v + (sumOfValues t1) sumOfValues (Node t1 v t2) = v + (sumOfValues t1) + (sumOfValues t2) It works as expected. I had the idea of also trying to implement it using guards: sumOfValues2 :: Tree -> Int sumOfValues2 Null = 0 sumOfValues2 (Node t1 v t2) | t1 == Null && t2 == Null = v | t1 == Null = v + (sumOfValues2 t2) | t2 == Null = v + (sumOfValues2 t1) | otherwise = v + (sumOfValues2 t1) + (sumOfValues2 t2) but this one doesn't work because I haven't implemented Eq, I believe: No instance for (Eq Tree) arising from a use of `==' at zzz3.hs:13:3-12 Possible fix: add an instance declaration for (Eq Tree) In the first argument of `(&&)', namely `t1 == Null' In the expression: t1 == Null && t2 == Null In a stmt of a pattern guard for the definition of `sumOfValues2': t1 == Null && t2 == Null The question that has to be made, then, is how can Haskell make pattern matching without knowing when a passed argument matches, without resorting to Eq?

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  • In Silverlight, what structures, aside of the ListBox, can be used for binding?

    - by Aidenn
    I need to simply provide the content of a property to a custom User Control in Silverlight. My control is something like this: <UserControl x:Class="SilverlightApplication.Header" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" mc:Ignorable="d" d:DesignWidth="300" d:DesignHeight="120"> <Grid x:Name="Header_Layout"> <StackPanel x:Name="hiHeaderContent" Width="Auto" Margin="73,8,8,8"> <TextBlock x:Name="User:" Text="{Binding name}" /> </StackPanel> </Grid> I try to use this User Control from another control where I try to pass the parameter "name" to the previous UserControl ("Header"). I don't need to create a "ListBox" as I will only have 1 header, so I try to avoid doing: <ListBox x:Name="HeaderListBox" Grid.Row="0"> <ListBox.ItemTemplate> <DataTemplate> <SilverlightApplication:Header/> </DataTemplate> </ListBox.ItemTemplate> </ListBox> in order to send the "User" account using: HeaderListBox.ItemsSource = name; Is there any other structure I can use instead of the ListBox to pass the parameter just once? It won't be a list, it's just a header... Thank you!

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  • How to parse mathematical expressions involving parentheses

    - by Rob P.
    Please forgive my title, I really don't know how to phrase it better. This isn't a school assignment or anything, but I realize it's a mostly academic question. But, what I've been struggling to do is parse 'math' text and come up with an answer. For Example - I can figure out how to parse '5 + 5' or '3 * 5' - but I fail when I try to correctly chain operations together. (5 + 5) * 3 It's mostly just bugging me that I can't figure it out. If anyone can point me in a direction, I'd really appreciate it. EDIT Thanks for all of the quick responses. I'm sorry I didn't do a better job of explaining. First - I'm not using regular expressions. I also know there are already libraries available that will take, as a string, a mathematical expression and return the correct value. So, I'm mostly looking at this because, sadly, I don't "get it". Second - What I've tried doing (is probably misguided) but I was counting '(' and ')' and evaluating the deepest items first. In simple examples, this worked; but my code is not pretty and more complicated stuff crashes. When I 'calculated' the lowest level, I was modifying the string. So... (5 + 5) * 3 Would turn into 10 * 3 Which would then evaluate to 30 But it just felt 'wrong'. I hope that helps clarify things. I'll certainly check out the links provided.

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  • Problem Binding to a Brush Property in WPF

    - by Krisc
    Working in WPF, writing a custom user control. I am trying to change the background property of the Border element when I change the value of a property of the class. Right now I am working on simply binding it to a DP, though if there is a better way I am open to suggestions. Here is the XAML for the UserControl <UserControl x:Class="MyProject.MyControl" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:js="clr-namespace:MyProject" mc:Ignorable="d" x:Name="MyControlRootLayout" Background="Transparent" d:DesignHeight="300" d:DesignWidth="300" Cursor="Hand"> <Border x:Name="RootBorder" Background="{Binding Path=CoreBackground, ElementName=MyControlRootLayout}" > </Border> </UserControl> And the code... public partial class MyControl : UserControl { public static DependencyProperty IsSelectedProperty = DependencyProperty.Register("IsSelected", typeof(bool), typeof(MyControl)); public static DependencyProperty CoreBackgroundProperty = DependencyProperty.Register("CoreBackground", typeof(Brush), typeof(MyControl)); public MyControl() { CoreBackground = new SolidColorBrush(Color.FromArgb(0, 255, 245, 104)); InitializeComponent(); Margin = new Thickness(5); } public Brush CoreBackground { get { return (Brush)GetValue(CoreBackgroundProperty); } set { SetValue(CoreBackgroundProperty, value); } } public bool IsSelected { get { return (bool)GetValue(IsSelectedProperty); } private set { SetValue(IsSelectedProperty, value); } } } Instead, the background comes out as transparent.

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  • Passing C++ object to C++ code through Python?

    - by cornail
    Hi all, I have written some physics simulation code in C++ and parsing the input text files is a bottleneck of it. As one of the input parameters, the user has to specify a math function which will be evaluated many times at run-time. The C++ code has some pre-defined function classes for this (they are actually quite complex on the math side) and some limited parsing capability but I am not satisfied with this construction at all. What I need is that both the algorithm and the function evaluation remain speedy, so it is advantageous to keep them both as compiled code (and preferrably, the math functions as C++ function objects). However I thought of glueing the whole simulation together with Python: the user could specify the input parameters in a Python script, while also implementing storage, visualization of the results (matplotlib) and GUI, too, in Python. I know that most of the time, exposing C++ classes can be done, e.g. with SWIG but I still have a question concerning the parsing of the user defined math function in Python: Is it possible to somehow to construct a C++ function object in Python and pass it to the C++ algorithm? E.g. when I call f = WrappedCPPGaussianFunctionClass(sigma=0.5) WrappedCPPAlgorithm(f) in Python, it would return a pointer to a C++ object which would then be passed to a C++ routine requiring such a pointer, or something similar... (don't ask me about memory management in this case, though :S) The point is that no callback should be made to Python code in the algorithm. Later I would like to extend this example to also do some simple expression parsing on the Python side, such as sum or product of functions, and return some compound, parse-tree like C++ object but let's stay at the basics for now. Sorry for the long post and thx for the suggestions in advance.

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  • Find all A^x in a given range

    - by Austin Henley
    I need to find all monomials in the form AX that when evaluated falls within a range from m to n. It is safe to say that the base A is greater than 1, the power X is greater than 2, and only integers need to be used. For example, in the range 50 to 100, the solutions would be: 2^6 3^4 4^3 My first attempt to solve this was to brute force all combinations of A and X that make "sense." However this becomes too slow when used for very large numbers in a big range since these solutions are used in part of much more intensive processing. Here is the code: def monoSearch(min, max): base = 2 power = 3 while 1: while base**power < max: if base**power > min: print "Found " + repr(base) + "^" + repr(power) + " = " + repr(base**power) power = power + 1 base = base + 1 power = 3 if base**power > max: break I could remove one base**power by saving the value in a temporary variable but I don't think that would make a drastic effect. I also wondered if using logarithms would be better or if there was a closed form expression for this. I am open to any optimizations or alternatives to finding the solutions.

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  • lambda expressions in VB.NET... what am I doing wrong???

    - by Bob
    when I run this C# code, no problems... but when I translate it into VB.NET it compiles but blows due to 'CompareString' member not being allowed in the expression... I feel like I'm missing something key here... private void PrintButton_Click(object sender, EventArgs e) { if (ListsListBox.SelectedIndex > -1) { //Context using (ClientOM.ClientContext ctx = new ClientOM.ClientContext(UrlTextBox.Text)) { //Get selected list string listTitle = ListsListBox.SelectedItem.ToString(); ClientOM.Web site = ctx.Web; ctx.Load(site, s => s.Lists.Where(l => l.Title == listTitle)); ctx.ExecuteQuery(); ClientOM.List list = site.Lists[0]; //Get fields for this list ctx.Load(list, l => l.Fields.Where(f => f.Hidden == false && (f.CanBeDeleted == true || f.InternalName == "Title"))); ctx.ExecuteQuery(); //Get items for the list ClientOM.ListItemCollection listItems = list.GetItems( ClientOM.CamlQuery.CreateAllItemsQuery()); ctx.Load(listItems); ctx.ExecuteQuery(); // DOCUMENT CREATION CODE GOES HERE } MessageBox.Show("Document Created!"); } } but in VB.NET code this errors due to not being allowed 'CompareString' members in the ctx.Load() methods... Private Sub PrintButton_Click(sender As Object, e As EventArgs) If ListsListBox.SelectedIndex > -1 Then 'Context Using ctx As New ClientOM.ClientContext(UrlTextBox.Text) 'Get selected list Dim listTitle As String = ListsListBox.SelectedItem.ToString() Dim site As ClientOM.Web = ctx.Web ctx.Load(site, Function(s) s.Lists.Where(Function(l) l.Title = listTitle)) ctx.ExecuteQuery() Dim list As ClientOM.List = site.Lists(0) 'Get fields for this list ctx.Load(list, Function(l) l.Fields.Where(Function(f) f.Hidden = False AndAlso (f.CanBeDeleted = True OrElse f.InternalName = "Title"))) ctx.ExecuteQuery() 'Get items for the list Dim listItems As ClientOM.ListItemCollection = list.GetItems(ClientOM.CamlQuery.CreateAllItemsQuery()) ctx.Load(listItems) ' DOCUMENT CREATION CODE GOES HERE ctx.ExecuteQuery() End Using MessageBox.Show("Document Created!") End If End Sub

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  • Why is T() = T() allowed?

    - by Rimo
    I believe the expression T() creates an rvalue (by the Standard). However, the following code compiles (at least on gcc4.0): class T {}; int main() { T() = T(); } I know technically this is possible because member functions can be invoked on temporaries and the above is just invoking the operator= on the rvalue temporary created from the first T(). But conceptually this is like assigning a new value to an rvalue. Is there a good reason why this is allowed? Edit: The reason I find this odd is it's strictly forbidden on built-in types yet allowed on user-defined types. For example, int(2) = int(3) won't compile because that is an "invalid lvalue in assignment". So I guess the real question is, was this somewhat inconsistent behavior built into the language for a reason? Or is it there for some historical reason? (E.g it would be conceptually more sound to allow only const member functions to be invoked on rvalue expressions, but that cannot be done because that might break some existing code.)

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  • page variable in a repeater

    - by carrot_programmer_3
    Hi I'm having a bit of an issue with a asp.net repeater I'm building a categories carousel with the dynamic categories being output by a repeater. Each item is a LinkButton control that passes an argument of the category id to the onItemClick handler. a page variable is set by this handler to track what the selected category id is.... public String SelectedID { get { object o = this.ViewState["_SelectedID"]; if (o == null) return "-1"; else return (String)o; } set { this.ViewState["_SelectedID"] = value; } } problem is that i cant seem to read this value while iterating through the repeater as follows... <asp:Repeater ID="categoriesCarouselRepeater" runat="server" onitemcommand="categoriesCarouselRepeater_ItemCommand"> <ItemTemplate> <%#Convert.ToInt32(Eval("CategoryID")) == Convert.ToInt32(SelectedID) ? "<div class=\"selectedcategory\">":"<div>"%> <asp:LinkButton ID="LinkButton1" CommandName="select_category" CommandArgument='<%#Eval("CategoryID")%>' runat="server"><img src="<%#Eval("imageSource")%>" alt="category" /><br /> </div> </ItemTemplate> </asp:Repeater> calling <%=SelectedID%> in the item template works but when i try the following expression the value of SelectedID returns empty.. <%#Convert.ToInt32(Eval("CategoryID")) == Convert.ToInt32(SelectedID) ? "match" : "not a match"%> the value is being set as follows... protected void categoriesCarouselRepeater_ItemCommand(object source, RepeaterCommandEventArgs e) { SelectedID = e.CommandArgument); } Any ideas whats wrong here?

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