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• How to change CSS color values in real-time off a javascript slider?

  - by bflora

  I'm making a page where the user gets a javascript slider that goes from 0 to 100 and can use it to set the opacity of a div on the page. I want the opacity of that div to change in real-time as they work the slider. I've not done this before. What's the best approach? There cursor in the slider displays the slider's current value as you move it. It seems to be that I just need to find a way to display that value in any arbitrary other place on the page so I can display it in the style settings for the div. The .js file that generates the slider has a line that (I think) is setting the current value in the cursor: $(this).children(".ui-slider-handle", context).html(parseInt(settings[index]['default'])); TO get this changing number to display somewhere else at the same time, do I just need to add a div somewhere and then add a line like this? $("#newDivId").children(".ui-slider-handle", context).html(parseInt(settings[index]['default'])); That seems like it would give me the number showing up in a div. How then would I get it into a form I could put into the style settings for a div? If this was a php variable, I would do something like this, style="opacity:<?php print $value ?>;" What would be the .js equivalent?

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• Google Bar Chart Time Label Interval

  - by Alex Angelini

  Hi I am using Google Bar Chart through the visualization API on my site: http://code.google.com/apis/visualization/documentation/gallery/imagebarchart.html And my x-axis is time, and every time interval is a time of day in the format (HH:MM) Here is my code for the graph: <script type="text/javascript" src="https://www.google.com/jsapi"></script> <script type="text/javascript"> %s google.load("visualization", "1", {packages:["imagebarchart"]}); google.setOnLoadCallback(drawChart); function drawChart() { var data = new google.visualization.DataTable(); data.addColumn('string', 'Date'); data.addColumn('number', 'Amount'); data.addRows({{Rows}}); %s var chart = new google.visualization.ImageBarChart(document.getElementById('chart_div')); chart.draw(data, {width: 900, height: 340, min: 0, isVertical:true, legend:'none'}); } </script> The rows of data are added later using a templating engine, but that is the jist of my chart. Because I have added my time variable as 'string' I cannot use the valueLabelsInterval option to only show every 4 labels. Because I can't do that the labels overlap and look ugly. Is there any other way to only show every other time label or every 4th one, I read through the docs but could not see how to do it. Any help would be greatly appreciated thanks

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• Mule ESB 3.2 Splitter destroys Enricher results

  - by Eddie

  Here is the snippet of my flow: <logger message="PRODUCT_ID = #[header:productID]" level="INFO" doc:name="Logger"/> <splitter evaluator="jxpath" expression="//*/BisacHeaderCodes" doc:name="Splitter"/> <logger message="PRODUCT_ID_POST_SPLITTER = #[header:productID]" level="INFO" doc:name="Logger"/> #[header:productID] was set up prior to Logger call. I tried #[variable:productID] and got the same result. When I run it, this is the out put I get: INFO 2012-04-05 23:12:47,865 [[bookinista_order_management].connector.http.mule.default.receiver.02] org.mule.api.processor.LoggerMessageProcessor: PRODUCT_ID = 72 ERROR 2012-04-05 23:12:47,871 [[bookinista_order_management].connector.http.mule.default.receiver.02] org.mule.exception.DefaultSystemExceptionStrategy: Caught exception in Exception Strategy: Expression Evaluator "header" with expression "outbound:productID" returned null but a value was required. org.mule.api.expression.RequiredValueException: Expression Evaluator "header" with expression "outbound:productID" returned null but a value was required. So, right before Splitter, I have a perfect value in my header, and right after Splitter, that value disappears! I understand that Splitter propagates only part of payloda, but shouldn't it leave headers and variables alone? Any ideas for a workaround?

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• How to add an extra plist property using CMake?

  - by Jesse Beder

  I'm trying to add the item <key>UIStatusBarHidden</key><true/> to my plist that's auto-generated by CMake. For certain keys, it appears there are pre-defined ways to add an item; for example: set(MACOSX_BUNDLE_ICON_FILE ${ICON}) But I can't find a way to add an arbitrary property. I tried using the MACOSX_BUNDLE_INFO_PLIST target property as follows: I'd like the resulting plist to be identical to the old one, except with the new property I want, so I just copied the auto-generated plist and set that as my template. But the plist uses some Xcode variables, which also look like ${foo}, and CMake grumbles about this: Syntax error in cmake code when parsing string <string>com.bedaire.${PRODUCT_NAME:identifier}</string> syntax error, unexpected cal_SYMBOL, expecting } (47) Policy CMP0010 is not set: Bad variable reference syntax is an error. Run "cmake --help-policy CMP0010" for policy details. Use the cmake_policy command to set the policy and suppress this warning. This warning is for project developers. Use -Wno-dev to suppress it. In any case, I'm not even sure that this is the right thing to do. I can't find a good example or any good documentation about this. Ideally, I'd just let CMake generate everything as before, and just add a single extra line. What can I do?

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• Accessing global variables of custom controls in ASP.NET

  - by CL4NCY

  Hi, I have built lots of custom asp.net controls which work really well separately but I want to somehow allow global access to all their variables from anywhere on the page. I have a central control called the ContentManager which I can use to store these variables. The problem I have is that all the controls are bound at different times so I only want the variables available after they're bound. For example I have many custom repeaters on the page which when bound I want to add a reference in the content manager so all their variables are then available to use. <Custom:ContentManager ID="cm" runat="server"/> <Custom:Repeater ID="r1" runat="server"/> <Custom:Repeater ID="r2" runat="server"/> <Custom:Repeater ID="r3" runat="server"/> Then I want a tag which can access all variables from any of these controls. <%= cm.controls["r1"].Items[0]["name"] %> The problem with this is that the variable isn't available until the repeater is bound so I might need to use events to push out the value to tags on the page like so: <Custom:Var ID="v1" control="r1" value="Items[0]["name"]" runat="server"/> Is this possible or can you recommend a better approach?

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• Android Camera intent creating two files

  - by Kyle Ramstad

  I am making a program that takes a picture and then shows it's thumbnail. When using the emulator all goes well and the discard button deletes the photo. But on a real device the camera intent saves the image at the imageUri variable and a second one that is named like if I had just opened up the camera and took a picture by itself. private static final int CAMERA_PIC_REQUEST = 1337; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.camera); //start camera values = new ContentValues(); values.put(MediaStore.Images.Media.TITLE, "New Picture"); values.put(MediaStore.Images.Media.DESCRIPTION,"From your Camera"); imageUri = getContentResolver().insert(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, values); image = (ImageView) findViewById(R.id.ImageView01); Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE); intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri); startActivityForResult(intent, CAMERA_PIC_REQUEST); //save the image buttons Button save = (Button) findViewById(R.id.Button01); Button close = (Button) findViewById(R.id.Button02); } @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { if (requestCode == CAMERA_PIC_REQUEST && resultCode == RESULT_OK) { try{ thumbnail = MediaStore.Images.Media.getBitmap(getContentResolver(), imageUri); image.setImageBitmap(thumbnail); } catch(Exception e){ e.printStackTrace(); } } else{ finish(); } } public void myClickHandler(View view) { switch (view.getId()) { case R.id.Button01: finish(); break; case R.id.Button02: dicard(); } } private void dicard(){ getContentResolver().delete(imageUri, null, null); finish(); }

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• Retaining Managed objects - more general retaining objects

  - by Luuk D. Jansen

  A quick question regarding Managed Objects. I created an Array with Managed Objects (in Object 1: TableViewConbtroller), and pass one of those objects to another class/object (object 2: TableCell). The original array should still be retained in the original caller class. Then Object 2 is released, does that mean that that particular item in the array is released as well, as the reference to it in Object 2 was released? I am trying to better understand how to work with ManagedObjects as I get 'Object was released' errors. [EDIT] After some experimenting I came across the following scenario: I have the main AppDelegate. In a different class I create an AppDelegate to obtain the ManagedObjectContext. appDelegate = (iDomsAppDelegate *)[[UIApplication sharedApplication] delegate]; [self setContext:[appDelegate managedObjectContext]]; When the class is finished, and I release it, the variable in the class 'appDelegate' is also released. But then the ManagedObjectContext is closed, and obvious any future attempt to use it will cause a crash. So should I leave the appDelegate unreleased? This comes to the same question as the above about when and how to release in those situations where an objects is used from another class. I think a way of putting it is, how to know when you own an object and when not.

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• Why does GLSL's arithmetic functions yield so different results on the iPad than on the simulator?

  - by cheeesus

  I'm currently chasing some bugs in my OpenGL ES 2.0 fragment shader code which is running on iOS devices. The code runs fine in the simulator, but on the iPad it has huge problems and some of the calculations yield vastly different results, I had for example 0.0 on the iPad and 4013.17 on the simulator, so I'm not talking about small differences which could be the result of some rounding errors. One of the things I noticed is that, on the iPad, float1 = pow(float2, 2.0); can yield results which are very different from the results of float1 = float2 * float2; Specifically, when using pow(x, 2.0) on a variable containing a larger negative number like -8, it seemed to return a value which satified the condition if (powResult <= 0.0). Also, the result of both operations (pow(x, 2.0) as well as x*x) yields different results in the simulator than on the iPad. Used floats are mediump, but I get the same stuff with highp. Is there a simple explanation for those differences? I'm narrowing the problem down, but it takes so much time, so maybe someone can help me here with a simple explanation.

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• define a closure as method from class

  - by user272839

  Hi, i'm trying to play with php5.3 and closure. I see here (Listing 7. Closure inside an object : http://www.ibm.com/developerworks/opensource/library/os-php-5.3new2/index.html) that it's possible to use $this in the callback function, but it's not. So I try to give $this as use variable : $self = $this; $foo = function() use($self) { //do something with $self } So to use the same example : class Dog { private $_name; protected $_color; public function __construct($name, $color) { $this->_name = $name; $this->_color = $color; } public function greet($greeting) { $self = $this; return function() use ($greeting, $self) { echo "$greeting, I am a {$self->_color} dog named {$self->_name}."; }; } } $dog = new Dog("Rover","red"); $dog->greet("Hello"); Output: Hello, I am a red dog named Rover. First of all this example does not print the string but return the function, but that's not my problem. Secondly I can't access to private or protected, because the callback function is a global function and not in the context from the Dog object. Tha't my problem. It's the same as : function greet($greeting, $object) { echo "$greeting, I am a {$self->_color} dog named {$self->_name}."; } And I want : public function greet($greeting) { echo "$greeting, I am a {$self->_color} dog named {$self->_name}."; } Which is from Dog and not global. I hope that I am clear ...

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• php request variables assigning $_GEt

  - by chris

  if you take a look at a previous question http://stackoverflow.com/questions/2690742/mod-rewrite-title-slugs-and-htaccess I am using the solution that Col. Shrapnel proposed- but when i assign values to $_GET in the actual file and not from a request the code doesnt work. It defaults away from the file as if the $_GET variables are not set The code I have come up with is- if(!empty($_GET['cat'])){ $_GET['target'] = "category"; if(isset($_GET['page'])){ $_GET['pageID'] = $_GET['page']; } $URL_query = "SELECT category_id FROM cats WHERE slug = '".$_GET['cat']."';"; $URL_result = mysql_query($URL_query); $URL_array = mysql_fetch_array($URL_result); $_GET['category_id'] = $URL_array['category_id']; }elseif($_GET['product']){ $_GET['target'] = "product"; $URL_query = "SELECT product_id FROM products WHERE slug = '".$_GET['product']."';"; $URL_result = mysql_query($URL_query); $URL_array = mysql_fetch_array($URL_result); print_r($URL_array); $_GET['product_id'] = $URL_array['product_id']; The original variable string that im trying to represent is /cart.php?Target=product&product_id=16142&category_id=249 And i'm trying to build the query string variables with code and including cart.php so i can use cleaner URL's So I have product/product-title-with-clean-url/ going to slug.php?product=slug Then the slug searches the db for a record with the matching slug and returns the product_id as in the code above.Then built the query string and include cart.php

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• Find all ways to insert zeroes into a bit pattern

  - by James

  I've been struggling to wrap my head around this for some reason. I have 15 bits that represent a number. The bits must match a pattern. The pattern is defined in the way the bits start out: they are in the most flush-right representation of that pattern. So say the pattern is 1 4 1. The bits will be: 000000010111101 So the general rule is, take each number in the pattern, create that many bits (1, 4 or 1 in this case) and then have at least one space separating them. So if it's 1 2 6 1 (it will be random): 001011011111101 Starting with the flush-right version, I want to generate every single possible number that meets that pattern. The # of bits will be stored in a variable. So for a simple case, assume it's 5 bits and the initial bit pattern is: 00101. I want to generate: 00101 01001 01010 10001 10010 10100 I'm trying to do this in Objective-C, but anything resembling C would be fine. I just can't seem to come up with a good recursive algorithm for this. It makes sense in the above example, but when I start getting into 12431 and having to keep track of everything it breaks down.

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• How to create a generic list in this wierd case in c#

  - by Marc Bettex

  Hello, In my program, I have a class A which is extended by B, C and many more classes. I have a method GetInstance() which returns a instance of B or C (or of one of the other child), but I don't know which one, so the return type of the method is A. In the method CreateGenericList(), I have a variable v of type A, which is in fact either a B, a C or another child type and I want to create a generic list of the proper type, i.e. List<B> if v is a B or List<C> if v is a C, ... Currently I do it by using reflection, which works, but this is extremely slow. I wanted to know if there is another way to to it, which doesn't use reflection. Here is an example of the code of my problem: class A { } class B : A { } class C : A { } // More childs of A. class Program { static A GetInstance() { // returns an instance of B or C } static void CreateGenericList() { A v = Program.GetInstance(); IList genericList = // Here I want an instance of List<B> or List<C> or ... depending of the real type of v, not a List<A>. } } I tried the following hack. I call the following method, hoping the type inferencer will guess the type of model, but it doesn't work and return a List<A>. I believe that because c# is statically typed, T is resolved as A and not as the real type of model at runtime. static List<T> CreateGenericListFromModel<T>(T model) where T : A { return new List<T> (); } Does anybody have a solution to that problem that doesn't use reflection or that it is impossible to solve that problem without reflection? Thank you very much, Marc

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• R: Are there any alternatives to loops for subsetting from an optimization standpoint?

  - by Adam

  A recurring analysis paradigm I encounter in my research is the need to subset based on all different group id values, performing statistical analysis on each group in turn, and putting the results in an output matrix for further processing/summarizing. How I typically do this in R is something like the following: data.mat <- read.csv("...") groupids <- unique(data.mat$ID) #Assume there are then 100 unique groups results <- matrix(rep("NA",300),ncol=3,nrow=100) for(i in 1:100) { tempmat <- subset(data.mat,ID==groupids[i]) #Run various stats on tempmat (correlations, regressions, etc), checking to #make sure this specific group doesn't have NAs in the variables I'm using #and assign results to x, y, and z, for example. results[i,1] <- x results[i,2] <- y results[i,3] <- z } This ends up working for me, but depending on the size of the data and the number of groups I'm working with, this can take up to three days. Besides branching out into parallel processing, is there any "trick" for making something like this run faster? For instance, converting the loops into something else (something like an apply with a function containing the stats I want to run inside the loop), or eliminating the need to actually assign the subset of data to a variable?

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• ASP.NET - Accessing copied content

  - by James Kolpack

  I have a class library project which contains some content files configured with the "Copy if newer" copy build action. This results in the files being copied to a folder under ...\bin\ for every project in the solution. In this same solution, I've got a ASP.NET web project (which is MVC, by the way). In the library I have a static constructor load the files into data structures accessible by the web project. Previously I've been including the content as an embedded resource. I now need to be able to replace them without recompiling. I want to access the data in three different contexts: Unit testing the library assembly Debugging the web application Hosting the site in IIS For unit testing, Environment.CurrentDirectory points to a path containing the copied content. When debugging however, it points to C:\Program Files\Microsoft Visual Studio 9.0\Common7\IDE. I've also looked at Assembly.GetExecutingAssembly().Location which points to C:\Windows\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\root\c44f9da4\9238ccc\assembly\dl3\eb4c23b4\9bd39460_f7d4ca01\. What I need is to the physical location of the webroot \bin folder, but since I'm in a static constructor in the library project, I don't have access to a Request.PhysicalApplicationPath. Is there some other environment variable or structure where I can always find my "Copy if newer" files?

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• Updating section in ConfigParser (or an alternative)

  - by lyrae

  I am making a plugin for another program and so I am trying to make thing as lightweight as possible. What i need to do is be able to update the name of a section in the ConfigParser's config file. [project name] author:john doe email: [email protected] year: 2010 I then have text fields where user can edit project's name, author, email and year. I don't think changing [project name] is possible, so I have thought of two solutions: 1 -Have my config file like this: [0] projectname: foobar author:john doe email: [email protected] year: 2010 that way i can change project's name just like another option. But the problem is, i would need the section # to be auto incremented. And to do this i would have to get every section, sort of, and figure out what the next number should be. The other option would be to delete the entire section and its value, and re-add it with the updated values which would require a little more work as well, such as passing a variable that holds the old section name through functions, etc, but i wouldn't mind if it's faster. Which of the two is best? or is there another way? I am willing to go with the fastest/lightweight solution possible, doesn't matter if it requires more work or not.

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• map operator [] operands

  - by Jamie Cook

  Hi all I have the following in a member function int tt = 6; vector<set<int>>& temp = m_egressCandidatesByDestAndOtMode[tt]; set<int>& egressCandidateStops = temp.at(dest); and the following declaration of a member variable map<int, vector<set<int>>> m_egressCandidatesByDestAndOtMode; However I get an error when compiling (Intel Compiler 11.0) 1>C:\projects\svn\bdk\Source\ZenithAssignment\src\Iteration\PtBranchAndBoundIterationOriginRunner.cpp(85): error: no operator "[]" matches these operands 1> operand types are: const std::map<int, std::vector<std::set<int, std::less<int>, std::allocator<int>>, std::allocator<std::set<int, std::less<int>, std::allocator<int>>>>, std::less<int>, std::allocator<std::pair<const int, std::vector<std::set<int, std::less<int>, std::allocator<int>>, std::allocator<std::set<int, std::less<int>, std::allocator<int>>>>>>> [ const int ] 1> vector<set<int>>& temp = m_egressCandidatesByDestAndOtMode[tt]; 1> ^ I know it's got to be something silly but I can't see what I've done wrong.

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• How should I define a JavaScript 'namespace' to satisfy JSLint?

  - by Matthew Murdoch

  I want to be able to package my JavaScript code into a 'namespace' to prevent name clashes with other libraries. Since the declaration of a namespace should be a simple piece of code I don't want to depend on any external libraries to provide me with this functionality. I've found various pieces of advice on how to do this simply but none seem to be free of errors when run through JSLint (using 'The Good Parts' options). As an example, I tried this from Advanced JavaScript (section Namespaces without YUI): "use strict"; if (typeof(MyNamespace) === 'undefined') { MyNamespace = {}; } Running this through JSLint gives the following errors: Problem at line 2 character 12: 'MyNamespace' is not defined. Problem at line 3 character 5: 'MyNamespace' is not defined. Implied global: MyNamespace 2,3 The 'Implied global' error can be fixed by explicitly declaring MyNamespace... "use strict"; if (typeof(MyNamespace) === 'undefined') { var MyNamespace = {}; } ...and the other two errors can be fixed by declaring the variable outside the if block. "use strict"; var MyNamespace; if (typeof(MyNamespace) === 'undefined') { MyNamespace = {}; } So that works, but it seems to me that (since MyNamespace will always be undefined at the point it is checked?) it is equivalent to the much simpler: "use strict"; var MyNamespace = {}; JSLint is content with this but I'm concerned that I've simplified the code to such an extent that it will no longer function correctly as a namespace. Is this final formulation sensible?

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• jsf, richfaces, popup window

  - by Hubidubi

  Hi I would like to make a list-detail view with richfaces. There will be a link for every record in the list that should open a new window containing record details. I tried to implement the link this way: <a4j:commandLink oncomplete="window.open('/pages/serviceDetail.jsf','popupWindow', 'dependent=yes, menubar=no, toolbar=no, height=500, width=400')" actionListener="#{monitoringBean.recordDetail}" value="details" /> I use <a4j:keepAlive beanName="monitoringBean" ajaxOnly="false" /> for both the list and the detail page. recordDetail method fills the data of the selected record to a variable of the bean that I would like to display on the detail page. The problem is that keepalive doesn't work, so I get new bean instance on the detail page every time. So the the previously selected record from the other bean is not accessible here. Is there a way to pass parameter (id) to the detail page to handle record selection. Or is there any way to make keepalive work? (I this this would be the easiest). Thanks

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• How do actually castings work at the CLR level?

  - by devoured elysium

  When doing an upcast or downcast, what does really happen behind the scenes? I had the idea that when doing something as: string myString = "abc"; object myObject = myString; string myStringBack = (string)myObject; the cast in the last line would have as only purpose tell the compiler we are safe we are not doing anything wrong. So, I had the idea that actually no casting code would be embedded in the code itself. It seems I was wrong: .maxstack 1 .locals init ( [0] string myString, [1] object myObject, [2] string myStringBack) L_0000: nop L_0001: ldstr "abc" L_0006: stloc.0 L_0007: ldloc.0 L_0008: stloc.1 L_0009: ldloc.1 L_000a: castclass string L_000f: stloc.2 L_0010: ret Why does the CLR need something like castclass string? There are two possible implementations for a downcast: You require a castclass something. When you get to the line of code that does an castclass, the CLR tries to make the cast. But then, what would happen had I ommited the castclass string line and tried to run the code? You don't require a castclass. As all reference types have a similar internal structure, if you try to use a string on an Form instance, it will throw an exception of wrong usage (because it detects a Form is not a string or any of its subtypes). Also, is the following statamente from C# 4.0 in a Nutshell correct? Upcasting and downcasting between compatible reference types performs reference conversions: a new reference is created that points to the same object. Does it really create a new reference? I thought it'd be the same reference, only stored in a different type of variable. Thanks

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• Is there a way to get the PREMATCH ($`) and POSTMATCH ($') from pcrecpp?

  - by Eric Peers

  Is there a way to obtain the C++ equivalent of Perl's PREMATCH ($`) and POSTMATCH ($') from pcrecpp? I would be happy with a string, a char *, or pairs indices/startpos+length that point at this. StringPiece seems like it might accomplish part of this, but I'm not certain how to get it. in perl: $_ = "Hello world"; if (/lo\s/) { $pre = $`; #should be "Hel" $post = $'; #should be "world" } in C++ I would have something like: string mystr = "Hello world"; //do I need to map this in a StringPiece? if (pcrecpp::RE("lo\s").PartialMatch(mystr)) { //should I use Consume or FindAndConsume? //What should I do here to get pre+post matches??? } pcre plainjane c seems to have the ability to return the vector with the matches including the "end" portion of the string, so I could theoretically extract such a pre/post variable, but that seems like a lot of work. I like the simplicty of the pcrecpp interface. Suggestions? Thanks! --Eric

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• Capacity Allocation

  - by user1708730

  I am new to VB in Excel. I have a unique requirement for capacity allocation which I want to automate using excel VB and facing hard time doing so, hope you can help. The objective is to maximize profit by allocating maximum capacity to those products which have highest profit potential first. Every Month I get demand along with backlogs of previous month. I need to allocate capacity to backlogs of previous month first and then only the remaining capacity for fresh demand. There are two primary constraints: 1.The number of working days in a month (variable) 2. Not all products can be made on every production line and out of same product may be different for each production line Also there will be losses whenever there is a change over from one SKU to another depending upon the Variant Type and size of next product. If there is variant change then 8 hours of production loss needs to be accounted and 4 hours in case of size change(8 hours in case of both). I have attached sample data(Actual data has 10 production lines and 50 products) https://rapidshare.com/files/1822719405/Sample%20Data.xlsx?bin=1 Thanks in advance for help!

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• Understanding the singleton class when aliasing a instance method

  - by Backo

  I am using Ruby 1.9.2 and the Ruby on Rails v3.2.2 gem. I am trying to learn Metaprogramming "the right way" and at this time I am aliasing an instance method in the included do ... end block provided by the RoR ActiveSupport::Concern module: module MyModule extend ActiveSupport::Concern included do # Builds the instance method name. my_method_name = build_method_name.to_sym # => :my_method # Defines the :my_method instance method in the including class of MyModule. define_singleton_method(my_method_name) do |*args| # ... end # Aliases the :my_method instance method in the including class of MyModule. singleton_class = class << self; self end singleton_class.send(:alias_method, :my_new_method, my_method_name) end end "Newbiely" speaking, with a search on the Web I came up with the singleton_class = class << self; self end statement and I used that (instead of the class << self ... end block) in order to scope the my_method_name variable, making the aliasing generated dynamically. I would like to understand exactly why and how the singleton_class works in the above code and if there is a better way (maybe, a more maintainable and performant one) to implement the same (aliasing, defining the singleton method and so on), but "the right way" since I think it isn't so.

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• Getting ellipses function parameters without an initial argument

  - by Tox1k

  So I've been making a custom parser for a scripting language, and I wanted to be able to pass only ellipses arguments. I don't need or want an initial variable, however Microsoft and C seem to want something else. FYI, see bottom for info. I've looked at the va_* definitions #define _crt_va_start(ap,v) ( ap = (va_list)_ADDRESSOF(v) + _INTSIZEOF(v) ) #define _crt_va_arg(ap,t) ( *(t *)((ap += _INTSIZEOF(t)) - _INTSIZEOF(t)) ) #define _crt_va_end(ap) ( ap = (va_list)0 ) and the part I don't want is the v in va_start. As a little background I'm competent in goasm and I know how the stack works so I know what's happening here. I was wondering if there is a way to get the function stack base without having to use inline assembly. Ideas I've had: #define im_va_start(ap) (__asm { mov [ap], ebp }) and etc... but really I feel like that's messy and I'm doing it wrong. struct function_table { const char* fname; (void)(*fptr)(...); unsigned char maxArgs; }; function_table mytable[] = { { "MessageBox", &tMessageBoxA, 4 } }; ... some function that sorts through a const char* passed to it to find the matching function in mytable and calls tMessageBoxA with the params. Also, the maxArgs argument is just so I can check that a valid number of parameters is being sent. I have personal reasons for not wanting to send it in the function, but in the meantime we can just say it's because I'm curious. This is just an example; custom libraries are what I would be implementing so it wouldn't just be calling WinAPI stuff. void tMessageBoxA(...) { // stuff to load args passed MessageBoxA(arg1, arg2, arg3, arg4); } I'm using the __cdecl calling convention and I've looked up ways to reliably get a pointer to the base of the stack (not the top) but I can't seem to find any. Also, I'm not worried about function security or typechecking.

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• Can this code cause a memory leak (Arduino)

  - by tbraun89

  I have a arduino project and I created this struct: struct Project { boolean status; String name; struct Project* nextProject; }; In my application I parse some data and create Project objects. To have them in a list there is a pointer to the nextProject in each Project object expect the last. This is the code where I add new projects: void RssParser::addProject(boolean tempProjectStatus, String tempData) { if (!startProject) { startProject = true; firstProject.status = tempProjectStatus; firstProject.name = tempData; firstProject.nextProject = NULL; ptrToLastProject = &firstProject; } else { ptrToLastProject->nextProject = new Project(); ptrToLastProject->nextProject->status = tempProjectStatus; ptrToLastProject->nextProject->name = tempData; ptrToLastProject->nextProject->nextProject = NULL; ptrToLastProject = ptrToLastProject->nextProject; } } firstProject is an private instance variable and defined in the header file like this: Project firstProject; So if there actually no project was added, I use firstProject, to add a new one, if firstProject is set I use the nextProject pointer. Also I have a reset() method that deletes the pointer to the projects: void RssParser::reset() { delete ptrToLastProject; delete firstProject.nextProject; startProject = false; } After each parsing run I call reset() the problem is that the memory used is not released. If I comment out the addProject method there are no issues with my memory. Someone can tell me what could cause the memory leak?

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• Semi-generic function

  - by Fredrik Ullner

  I have a bunch of overloaded functions that operate on certain data types such as int, double and strings. Most of these functions perform the same action, where only a specific set of data types are allowed. That means I cannot create a simple generic template function as I lose type safety (and potentially incurring a run-time problem for validation within the function). Is it possible to create a "semi-generic compile time type safe function"? If so, how? If not, is this something that will come up in C++0x? An (non-valid) idea; template <typename T, restrict: int, std::string > void foo(T bar); ... foo((int)0); // OK foo((std::string)"foobar"); // OK foo((double)0.0); // Compile Error Note: I realize I could create a class that has overloaded constructors and assignment operators and pass a variable of that class instead to the function.

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