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• How to set a static system date for one user or application--"Groundhog Day"

  - by aixylinux

  I have a vendor application on AIX which requires the system date to be set to an arbitrary value for QA testing purposes. The application gets its date from the system, and there is no possibility of changing it to get the date from a parameter. The application runs under a specific userid. I'd like to find a way to set the date for this application or user to a private value without affecting all the other users and applications on the system. So far the only thing I have been able to do is dedicate an LPAR to this application. Every day at midnight a root crontab job resets the date to the static value. This works, but it is wasteful of resources; and now I am faced the requirement to do this for other applications, which, of course, require different dates. Is there any clever solution to this? I need a way to create a sandboxed environment where the date returned from the system can be set to a private value. As I said, the OS is AIX, and that can't be changed for this application either.

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• Is there bug in the Matrix.RotateAt method for certain angles? .Net Winforms

  - by Jules

  Here's the code i'm using to rotate: Dim m As New System.Drawing.Drawing2D.Matrix Dim size = image.Size m.RotateAt(degreeAngle, New PointF(CSng(size.Width / 2), CSng(size.Height / 2))) Dim temp As New Bitmap(600, 600, Imaging.PixelFormat.Format32bppPArgb) Dim g As Graphics = Graphics.FromImage(temp) g.Transform = m g.DrawImage(image, 0, 0) (1) Disposals removed for brevity. (2) I test the code with a 200 x 200 rectangle. (3) Size 600,600 it just an arbitrary large value that I know will fit the right and bottom sides of the rotated image for testing purposes. (4) I know, with this code, the top and left edges will be clipped because I'm not transforming the orgin after the rotate. The problem only occurs at certain angles: (1) At 90, the right hand edge disappears completely. (2) At 180, the right and bottom edges are there, but very faded. (3) At 270, the bottom edge disappears completely. Is this a known bug? If I manually rotate the corners an draw the image by specifying an output rectangle, I don't get the same problem - though it is slightly slower than using RotateAt.

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• ForEach loop in Mathematica.

  - by dreeves

  I'd like something like this: ForEach[i_, {1,2,3}, Print[i] ] Or, more generally, to destructure arbitrary stuff in the list you're looping over, like: ForEach[{i_, j_}, {{1,10}, {2,20}, {3,30}}, Print[i*j] ] (Meta-question: is that a good way to call a ForEach loop, with the first argument a pattern like that?) ADDED: Some answerers have rightly pointed out that usually you want to use Map or other purely functional constructs and eschew a non-functional programming style where you use side effects. I agree! But here's an example where I think this ForEach construct is supremely useful: Say I have a list of options (rules) that pair symbols with expressions, like attrVals = {a -> 7, b -> 8, c -> 9} Now I want to make a hash table where I do the obvious mapping of those symbols to those numbers. I don't think there's a cleaner way to do that than ForEach[a_ -> v_, attrVals, h[a] = v] ADDED: I just realized that to do ForEach properly, it should support Break[] and Continue[]. I'm not sure how to implement that. Perhaps it will need to somehow be implemented in terms of For, While, or Do since those are the only loop constructs that support Break[] and Continue[]. If anyone interested in this wants to ask about that as a separate question, please do!

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• How to draw shadows that don't suck?

  - by mystify

  A CAShapeLayer uses a CGPathRef to draw it's stuff. So I have a star path, and I want a smooth drop shadow with a radius of about 15 units. Probably there is some nice functionality in some new iPhone OS versions, but I need to do it myself for a old aged version of 3.0 (which most people still use). I tried to do some REALLY nasty stuff: I created a for-loop and sequentially created like 15 of those paths, transform-scaling them step by step to become bigger. Then assigning them to a new created CAShapeLayer and decreasing it's alpha a little bit on every iteration. Not only that this scaling is mathematically incorrect and sucks (it should happen relative to the outline!), the shadow is not rounded and looks really ugly. That's why nice soft shadows have a radius. The tips of a star shouldn't appear totally sharp after a shadow size of 15 units. They should be soft like cream. But in my ugly solution they're just as s harp as the star itself, since all I do is scale the star 15 times and decrease it's alpha 15 times. Ugly. I wonder how the big guys do it? If you had an arbitrary path, and that path must throw a shadow, how does the algorithm to do that work? Probably the path would have to be expanded like 30 times, point-by-point relative to the tangent of the outline away from the filled part, and just by 0.5 units to have a nice blending. Before I re-invent the wheel, maybe someone has a handy example or link?

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• Computation overhead in C# - Using getters/setters vs. modifying arrays directly and casting speeds

  - by Jeffrey Kern

  I was going to write a long-winded post, but I'll boil it down here: I'm trying to emulate the graphical old-school style of the NES via XNA. However, my FPS is SLOW, trying to modify 65K pixels per frame. If I just loop through all 65K pixels and set them to some arbitrary color, I get 64FPS. The code I made to look-up what colors should be placed where, I get 1FPS. I think it is because of my object-orented code. Right now, I have things divided into about six classes, with getters/setters. I'm guessing that I'm at least calling 360K getters per frame, which I think is a lot of overhead. Each class contains either/and-or 1D or 2D arrays containing custom enumerations, int, Color, or Vector2D, bytes. What if I combined all of the classes into just one, and accessed the contents of each array directly? The code would look a mess, and ditch the concepts of object-oriented coding, but the speed might be much faster. I'm also not concerned about access violations, as any attempts to get/set the data in the arrays will done in blocks. E.g., all writing to arrays will take place before any data is accessed from them. As for casting, I stated that I'm using custom enumerations, int, Color, and Vector2D, bytes. Which data types are fastest to use and access in the .net Framework, XNA, XBox, C#? I think that constant casting might be a cause of slowdown here. Also, instead of using math to figure out which indexes data should be placed in, I've used precomputed lookup tables so I don't have to use constant multiplication, addition, subtraction, division per frame. :)

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• How to -accurately- measure size in pixels of text being drawn on a canvas by drawTextOnPath()

  - by Nick

  I'm using drawTextOnPath() to display some text on a Canvas and I need to know the dimensions of the text being drawn. I know this is not feasible for paths composed of multiple segments, curves, etc. but my path is a single segment which is perfectly horizontal. I am using Paint.getTextBounds() to get a Rect with the dimensions of the text I want to draw. I use this rect to draw a bounding box around the text when I draw it at an arbitrary location. Here's some simplified code that reflects what I am currently doing: // to keep this example simple, always at origin (0,0) public drawBoundedText(Canvas canvas, String text, Paint paint) { Rect textDims = new Rect(); paint.getTextBounds(text,0, text.length(), textDims); float hOffset = 0; float vOffset = paint.getFontMetrics().descent; // vertically centers text float startX = textDims.left; / 0 float startY = textDims.bottom; float endX = textDims.right; float endY = textDims.bottom; path.moveTo(startX, startY); path.lineTo(endX, endY); path.close(); // draw the text canvas.drawTextOnPath(text, path, 0, vOffset, paint); // draw bounding box canvas.drawRect(textDims, paint); } The results are -close- but not perfect. If I replace the second to last line with: canvas.drawText(text, startX, startY - vOffset, paint); Then it works perfectly. Usually there is a gap of 1-3 pixels on the right and bottom edges. The error seems to vary with font size as well. Any ideas? It's possible I'm doing everything right and the problem is with drawTextOnPath(); the text quality very visibly degrades when drawing along paths, even if the path is horizontal, likely because of the interpolation algorithm or whatever its using behind the scenes. I wouldnt be surprised to find out that the size jitter is also coming from there.

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• Multiple plugin instance loading with MEF

  - by Dave

  In my last application, using MEF to load plugins went just fine, but now I'm running into a new issue. I have a solution for it that I explain at the end of this question, but I'm looking for other ways to do it. Let's say I have an interface called ApplianceInterface. I also have two plugins that inherit from ApplianceInterface, let's call them Blender and Processor. Now, I would like to have multiple Blenders and Processors in my application, but I am not sure how to instantiate them properly. Before, I would simply use the ImportMany attribute and upon calling ComposeParts, my application would load Blender and Processor. For example: [ImportMany(typeof(ApplianceInterface))] private IEnumerable<ApplianceInterface> Appliances { get; set; } and my Blender and Processor plugins would be attributed like this: [PartCreationPolicy(CreationPolicy.NonShared)] [Export(typeof(MyInterface)] public class Blender : ApplianceInterface { ... } but what this ends up doing for me is populating Appliances with one Blender and one Processor. I need to be able to create an arbitrary number of Blender and Processor objects. Now, from the documentation I understand that [PartCreationPolicy(CreationPolicy.NonShared)] is what allows MEF to create a new instance each time, but is there a similar "magical" way to create a specific number of instances of something using MEF? Up until now, I've relied on [Import] and [ImportMany] to resolve the assemblies. Is my only option to use a global container, and then resolve the export manually using GetExportedValue<? I have tried GetExportedValue< and that implementation does work fine for me, but I was just curious if there is a better, more accepted way to do it.

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• Can the Visual Studio (2010) Command Window handle "external tools" with project/solution relative p

  - by ee

  I have been playing with the Command Window in Visual Studio (View-Other Windows-Command Window). It is great for several mouse-free scenarios. (The autocompleting file "Open" command rocks in a non-trivial solution.) That success got me thinking and experimenting: Possibility 1.1: You can use the Alias commands to create custom commands Possibility 1.2: You can use the Shell command to run arbitrary executables and specify parameters (and pipe the result to the output or command windows) Possibility 2: A previously setup external tool definition (with project-relative path variables) could be run from the command window What I am stuck on is: There doesn't appear to be a way to send parameters to an aliased command (and thus the underlying Shell call) There doesn't appear to be a way to use project/solution relative paths ($SolutionDir/$ProjectDir) on a Shell call Using absolute paths in Shell works, but is fragile and high-maintenance (one alias for each needed use case). Typically you want the command to run against a file relative to your project/solution. It seems you can't run the traditional external tools (Tools-External Tools...) in the command window Ultimately I want the external tool functionality in the command window in some way. Can anyone see a way to do this? Or am I barking up the wrong tree? So my questions: Can an "external tool" of some sort (using relative project/solution path parameters) be used in the Command Window? If yes, How? If no, what might be a suitable alternative?

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• How to cancel a deeply nested process

  - by Mystere Man

  I have a class that is a "manager" sort of class. One of it's functions is to signal that the long running process of the class should shut down. It does this by setting a boolean called "IsStopping" in class. public class Foo { bool isStoping void DoWork() { while (!isStopping) { // do work... } } } Now, DoWork() was a gigantic function, and I decided to refactor it out and as part of the process broke some of it into other classes. The problem is, Some of these classes also have long running functions that need to check if isStopping is true. public class Foo { bool isStoping void DoWork() { while (!isStopping) { MoreWork mw = new MoreWork() mw.DoMoreWork() // possibly long running // do work... } } } What are my options here? I have considered passing isStopping by reference, which I don't really like because it requires there to be an outside object. I would prefer to make the additional classes as stand alone and dependancy free as possible. I have also considered making isStopping a property, and then then having it call an event that the inner classes could be subscribed to, but this seems overly complex. Another option was to create a "Process Cancelation Token" class, similar to what .net 4 Tasks use, then that token be passed to those classes. How have you handled this situation? EDIT: Also consider that MoreWork might have a EvenMoreWork object that it instantiates and calls a potentially long running method on... and so on. I guess what i'm looking for is a way to be able to signal an arbitrary number of objects down a call tree to tell them to stop what they're doing and clean up and return.

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• How can data templates in generic.xaml get applied automatically?

  - by Thiado de Arruda

  I have a custom control that has a ContentPresenter that will have an arbitrary object set as it content. This object does not have any constraint on its type, so I want this control to display its content based on any data templates defined by application or by data templates defined in Generic.xaml. If in a application I define some data template(without a key because I want it to be applied automatically to objects of that type) and I use the custom control bound to an object of that type, the data template gets applied automatically. But I have some data templates defined for some types in the generic.xaml where I define the custom control style, and these templates are not getting applied automatically. Here is the generic.xaml : If I set an object of type 'PredefinedType' as the content in the contentpresenter, the data template does not get applied. However, If it works if I define the data template in the app.xaml for the application thats using the custom control. Does someone got a clue? I really cant assume that the user of the control will define this data template, so I need some way to tie it up with the custom control.

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• Help me find article on Multi-threading and Event Handling in Java

  - by JDR

  I once read an article on how to properly write event handlers for multi-threading in Java, but I can't for the life of me find it anymore. It described the pitfalls and potentials for deadlocks that can occur when firing events (not Swing events mind you, but general events like model update notifications). To clarify, the situation would be as such: // let's say this is code from an MVC model somewhere public void setSomeProperty(String myProperty){ if(!this.myProperty.equals(myProperty)){ this.myProperty = myProperty; fireMyPropertyChangedEvent(...); } } The article described how passing control to arbitrary external listener code was a potential cause for deadlock. I now find myself in a situation where I need to fire such events in a multithreaded environment and I would very much like to read the article again to see what it has to say before I continue. Does anyone know the article I'm referring to? I believe it came as a (fairly short) PDF. It started off with an initial naive implementation and incrementally pointed out flaws and improved upon it. It ended with a sort of final proper-way-to-fire-multithreaded-events. I've searched endlessly in my browse history and on google, but all I could find were endless amounts topics on Swing event dispatch threads. Thank you.

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• Retrieving my own data via FaceBook API

  - by goggin13

  I am building a website for a comedy group which uses Facebook as one of their marketing platforms; one of the requirements for the new site is to display all of their Facebook events on a calendar. Currently, I am just trying to put together a Python script which can pull some data from my own Facebook account, like a list of all my friends. I presume once I can accomplish this I can move to pulling more complicated data out of my clients account (since they have given me access to their account). I have looked at many of the posts here, and also went through the Facebook API documentation, including Facebook Connect, but am really beating my head against the wall. Everything I have read seems like overkill, as it involves setting up a good deal of infrastructure to allow my app to set up connections to any arbitrary user's account (who authorizes me). Shouldn't it be much simpler, given I only ever need to access 1 account? I cannot find a way to retrieve data without having to display the Facebook login window. I have a script which will retrieve all my friends, but it includes a redirect where I have to physically log myself in to Facebook. Would appreciate any advice or links, I just feel like I must be missing something simple. Thank you!

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• Any techniques to interrupt, kill, or otherwise unwind (releasing synchronization locks) a single de

  - by gojomo

  I have a long-running process where, due to a bug, a trivial/expendable thread is deadlocked with a thread which I would like to continue, so that it can perform some final reporting that would be hard to reproduce in another way. Of course, fixing the bug for future runs is the proper ultimate resolution. Of course, any such forced interrupt/kill/stop of any thread is inherently unsafe and likely to cause other unpredictable inconsistencies. (I'm familiar with all the standard warnings and the reasons for them.) But still, since the only alternative is to kill the JVM process and go through a more lengthy procedure which would result in a less-complete final report, messy/deprecated/dangerous/risky/one-time techniques are exactly what I'd like to try. The JVM is Sun's 1.6.0_16 64-bit on Ubuntu, and the expendable thread is waiting-to-lock an object monitor. Can an OS signal directed to an exact thread create an InterruptedException in the expendable thread? Could attaching with gdb, and directly tampering with JVM data or calling JVM procedures allow a forced-release of the object monitor held by the expendable thread? Would a Thread.interrupt() from another thread generate a InterruptedException from the waiting-to-lock frame? (With some effort, I can inject an arbitrary beanshell script into the running system.) Can the deprecated Thread.stop() be sent via JMX or any other remote-injection method? Any ideas appreciated, the more 'dangerous', the better! And, if your suggestion has worked in personal experience in a similar situation, the best!

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• Full and Partial Matching of Sets

  - by jeffrey

  I have several sets of the same type [Y, M, D] and am trying to write a function to search these sets and return an array of the available sets that fit my parameters. ReturnedSets = return_matches(Y,M,D); I want the three parameters of the function return_matches to be optional. Which means any combination of values can be used to return the sets. For example, one could write - return_matches(13,null,2); - and the function would look for all sets that contain [13, anyValue, 2]; I'm writing this in PHP, to allow users to manage dated files on my website, but I'd like to be able to use this function again for other uses. Thanks! edit: (This, or variations of this, is all I can come up with so far... There is something extra that I don't understand, because this function ends up / would not work to return sets that contain y and d, but leaving m arbitrary. if(y == s[0]){ if(m == s[1]){ if(d == s[2]){ print "day match"; } } else {print "month match";} } else {print "year match";} } else {print "no match";}

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• Why is Excel's 'Evaluate' method a general expression evaluator?

  - by jtolle

  A few questions have come up recently involving the Application.Evaluate method callable from Excel VBA. The old XLM macro language also exposes an EVALUATE() function. Both can be quite useful. Does anyone know why the evaluator that is exposed can handle general expressions, though? My own hunch is that Excel needed to give people a way to get ranges from string addresses, and to get the value of named formulas, and just opening a portal to the expression evaluator was the easiest way. (The help for the VBA version does say its purpose it to "convert a Microsoft Excel name to an object or a value".) But of course you don't need the ability to evaluate arbitrary expressions just to do that. (That is, Excel could provide a Name.Evaluate method or something instead.) Application.Evaluate seems kind of...unfinished. It's full behavior isn't very well documented, and there are quite a few quirks and limitations (as described by Charles Williams here: http://www.decisionmodels.com/calcsecretsh.htm) with what is exposed. I suppose the answer could be simply "why not expose it?", but I'd be interested to know what design decisions led to this feature taking the form that it does. Failing that, I'd be interested to hear other hunches.

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• Automatically use inclusion tags (?) in a template, depending on installed apps

  - by Ludwik Trammer

  The title may be a little confusing, but I don't know how else to call it. I would like to create a Django project with a large set of applications you could arbitrary turn on or off using INSTALLED_APPS option in settings.py (you would obviously also need to edit urls.py and run syncdb). After being turned on an app should be able to automatically: Register it's content in site-wide search. Luckily django-haystack has this built-in, so it's not a problem. Register cron jobs. django-cron does exactly that. Not a problem. Register a widget that should be displayed on the homepage. The homepage should include a list of boxes with widgets form different applications. I thought about inclusion tags, because you can put them anywhere on a page and they control both content and presentation. The problem is I don't know how to automatically get a list of inclusion tags provided by my applications, and display them one by one on a homepage. I need a way to register them somehow, and then display all registered tags.

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• Looping through a method without for/foreach/while

  - by RichK

  Is there a way of calling a method/lines of code multiple times not using a for/foreach/while loop? For example, if I were to use to for loop: int numberOfIterations = 6; for(int i = 0; i < numberOfIterations; i++) { DoSomething(); SomeProperty = true; } The lines of code I'm calling don't use 'i' and in my opinion the whole loop declaration hides what I'm trying to do. This is the same for a foreach. I was wondering if there's a looping statement I can use that looks something like: do(6) { DoSomething(); SomeProperty = true; } It's really clear that I just want to execute that code 6 times and there's no noise involving index instantiating and adding 1 to some arbitrary variable. As a learning exercise I have written a static class and method: Do.Multiple(int iterations, Action action) Which works but scores very highly on the pretentious scale and I'm sure my peers wouldn't approve. I'm probably just being picky and a for loop is certainly the most recognisable, but as a learning point I was just wondering if there (cleaner) alternatives. Thanks. (I've had a look at this thread, but it's not quite the same) http://stackoverflow.com/questions/2248985/using-ienumerable-without-foreach-loop

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• Reordering columns (fields) in a ADO Recordset

  - by Sukotto

  I have a classic asp webpage written in vbscript that outputs the results from a third-party stored procedure. My user wants the page to display the columns of data in a different order than they come in from the database. Is there an easy and safe way to re-order the columns in an ADO recordset? I did not write this page and cannot change the SP. What is the minimum change I can make here to get the job done and not risk screwing up all the other stuff in the page? The code looks something like dim Conn, strSQL, RS Set Conn = Server.CreateObject("ADODB.Connection") Conn.Open ServerName Set strSQL = "EXEC storedProc @foo = " & Request("fooParam") 'This stored procedure returns a date column, an arbitrary ' ' number of data columns, and two summation columns. We ' ' want the two summation columns to move so they appear ' ' immediately after the data column ' Set RS = Server.CreateObject("ADODB.RecordSet") RS.ActiveConnection = Nothing RS.CursorLocation = adUseClient RS.CursorType = adOpenStatic RS.LockType = adLockBatchOptimistic RS.Open strSQL, Conn, adOpenDynamic, adLockOptimistic dim A ' ----- ' ' Insert some code here to move the columns of the RS around ' ' to suit the whim of my user ' ' ----- ' ' Several blocks of code that iterate over the RS and display it various ways ' RS.MoveFirst For A = 0 To RS.Fields.Count -1 ' do stuff ' Next ... RS.MoveFirst For A = 0 To RS.Fields.Count -1 ' do more stuff ' Next RS.Close : Set RS = Nothing Conn.Close : Set Conn = Nothing

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• Does Monitor.Wait ensure that fields are re-read?

  - by Marc Gravell

  It is generally accepted (I believe!) that a lock will force any values from fields to be reloaded (essentially acting as a memory-barrier or fence - my terminology in this area gets a bit loose, I'm afraid), with the consequence that fields that are only ever accessed inside a lock do not themselves need to be volatile. (If I'm wrong already, just say!) A good comment was raised here, questioning whether the same is true if code does a Wait() - i.e. once it has been Pulse()d, will it reload fields from memory, or could they be in a register (etc). Or more simply: does the field need to be volatile to ensure that the current value is obtained when resuming after a Wait()? Looking at reflector, Wait calls down into ObjWait, which is managed internalcall (the same as Enter). The scenario in question was: bool closing; public bool TryDequeue(out T value) { lock (queue) { // arbitrary lock-object (a private readonly ref-type) while (queue.Count == 0) { if (closing) { // <==== (2) access field here value = default(T); return false; } Monitor.Wait(queue); // <==== (1) waits here } ...blah do something with the head of the queue } } Obviously I could just make it volatile, or I could move this out so that I exit and re-enter the Monitor every time it gets pulsed, but I'm intrigued to know if either is necessary.

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• Permuting output of a tree of closures

  - by yan

  This a conceptual question on how one would implement the following in Lisp (assuming Common Lisp in my case, but any dialect would work). Assume you have a function that creates closures that sequentially iterate over an arbitrary collection (or otherwise return different values) of data and returns nil when exhausted, i.e. (defun make-counter (up-to) (let ((cnt 0)) (lambda () (if (< cnt up-to) (incf cnt) nil)))) CL-USER> (defvar gen (make-counter 3)) GEN CL-USER> (funcall gen) 1 CL-USER> (funcall gen) 2 CL-USER> (funcall gen) 3 CL-USER> (funcall gen) NIL CL-USER> (funcall gen) NIL Now, assume you are trying to permute a combinations of one or more of these closures. How would you implement a function that returns a new closure that subsequently creates a permutation of all closures contained within it? i.e.: (defun permute-closures (counters) ......) such that the following holds true: CL-USER> (defvar collection (permute-closures (list (make-counter 3) (make-counter 3)))) CL-USER> (funcall collection) (1 1) CL-USER> (funcall collection) (1 2) CL-USER> (funcall collection) (1 3) CL-USER> (funcall collection) (2 1) ... and so on. The way I had it designed originally was to add a 'pause' parameter to the initial counting lambda such that when iterating you can still call it and receive the old cached value if passed ":pause t", in hopes of making the permutation slightly cleaner. Also, while the example above is a simple list of two identical closures, the list can be an arbitrarily-complicated tree (which can be permuted in depth-first order, and the resulting permutation set would have the shape of the tree.). I had this implemented, but my solution wasn't very clean and am trying to poll how others would approach the problem. Thanks in advance.

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• why does django-registration use an "activation window" for activating accounts?

  - by bharal

  i'm using django-registration, which is a django lib that helps with users registering on a django-built website. All well and dandy, except that it insists i have an "activation email" associated with all new users. It defaults to a 7 day window, after which, if someone signed up (and we then sent an email to confirm their email address) but didn't click on the link in the sent email within the 7 days, then they cannot sign up. Instead, they need to do the whole process all over again. I'm sure this is a concept that exists generally in web design, because why would django-registration make its own arbitrary signup process up? Anyway, the question is why? What do i gain by having the peace of mind knowing that all the users of my site are the kind of go-getters that click on registration emails with 7 days of receiving them? Why should i sleep easier knowing that my database isn't filled with users who, for whatever reason, clicked through to sign up but didn't actually want to sign up? cheers!

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• Managing server instance identity on EC2

  - by kikibobo

  I recently brought up a cluster on EC2, and I felt like I had to invent a lot of things. I'm wondering what kinds of tools, patterns, ideas are out there for how to deal with this. Some context: I had 3 different kinds of servers, so first I created AMIs for each of them. The first AMI had zookeeper, so step one in deploying the system was to get the zookeeper server running. My script then made a note of the mapping between EC2's completely arbitrary and unpredictable hostnames, and the zookeeper server. Then as I brought up new instances of the other 2 kinds of servers, the first thing I would do is ssh to the new server, and add the zookeeper server to its /etc/hosts file. Then as the server software on each instance starts up, it can find zookeeper. Obviously this is a problem that lots of people have to solve, and it probably works a little bit differently in different clouds. Are there products that address this concept? I was pretty surprised that EC2 didn't provide some kind of way to tie your own name to its name. Thanks for any ideas.

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• Can I set NHibernate's default "OrderBy" to be "CreatedDate" not "Id"?

  - by Chris F

  This is an oddball question I figure. Can I get NHibernate to ask SQL to sort data by CreatedDate by default unless I set an OrderBy in my HQL or Criteria? I'm interested in knowing whether this sort can be accomplished at the DB level to avoid bringing in LINQ. The reason is that I use GUIDs for Ids and when I do something like this: Sheet sheet = sheetRepository.Get(_someGUID); IList<SheetLineItems> lineItems = sheet.LineItems; to fetch all of the lineItems, they come back in whatever arbitrary way that SQL sorts that fetch, which I figure is GUID. At some point I'll add ordinals to my line items, but for now, I just want to use CreatedDate as the sort criteria. I don't want to be forced to do: IList<SheetLineItem> lineItems = sheetLineItemRepository.GetAll(_sheetGUID); and then writing that method to sort by CreatedDate. I figure if everything is just sorted on CreatedDate by default, that would be fine, unless specifically requested otherwise.

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• Optimize Duplicate Detection

  - by Dave Jarvis

  Background This is an optimization problem. Oracle Forms XML files have elements such as: <Trigger TriggerName="name" TriggerText="SELECT * FROM DUAL" ... /> Where the TriggerText is arbitrary SQL code. Each SQL statement has been extracted into uniquely named files such as: sql/module=DIAL_ACCESS+trigger=KEY-LISTVAL+filename=d_access.fmb.sql sql/module=REP_PAT_SEEN+trigger=KEY-LISTVAL+filename=rep_pat_seen.fmb.sql I wrote a script to generate a list of exact duplicates using a brute force approach. Problem There are 37,497 files to compare against each other; it takes 8 minutes to compare one file against all the others. Logically, if A = B and A = C, then there is no need to check if B = C. So the problem is: how do you eliminate the redundant comparisons? The script will complete in approximately 208 days. Script Source Code The comparison script is as follows: #!/bin/bash echo Loading directory ... for i in $(find sql/ -type f -name \*.sql); do echo Comparing $i ... for j in $(find sql/ -type f -name \*.sql); do if [ "$i" = "$j" ]; then continue; fi # Case insensitive compare, ignore spaces diff -IEbwBaq $i $j > /dev/null # 0 = no difference (i.e., duplicate code) if [ $? = 0 ]; then echo $i :: $j >> clones.txt fi done done Question How would you optimize the script so that checking for cloned code is a few orders of magnitude faster? System Constraints Using a quad-core CPU with an SSD; trying to avoid using cloud services if possible. The system is a Windows-based machine with Cygwin installed -- algorithms or solutions in other languages are welcome. Thank you!

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• C# assign values of array to separate variables in one line

  - by Sarah Vessels

  Can I assign each value in an array to separate variables in one line in C#? Here's an example in Ruby code of what I want: irb(main):001:0> str1, str2 = ["hey", "now"] => ["hey", "now"] irb(main):002:0> str1 => "hey" irb(main):003:0> str2 => "now" I'm not sure if what I'm wanting is possible in C#. Edit: for those suggesting I just assign the strings "hey" and "now" to variables, that's not what I want. Imagine the following: irb(main):004:0> val1, val2 = get_two_values() => ["hey", "now"] irb(main):005:0> val1 => "hey" irb(main):006:0> val2 => "now" Now the fact that the method get_two_values returned strings "hey" and "now" is arbitrary. In fact it could return any two values, they don't even have to be strings.

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