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• When is it possible to override top-level bindings in (R7RS) scheme?

  - by Marc

  I have read the current draft of the forthcoming R7RS scheme standard (small language), but I don't understand under which conditions it is not an error to redefine top-level bindings. I guess that it is possible to define or set! a binding that has been introduced at the top-level of a program a second time. But what about imported bindings from an external library? Is it possible to override these bindings by the standard? On page 26/27 of the report, it says: The top level of a program may also include import declarations. In a library declaration, it is an error to import the same identifier more than once with different bindings, or to redefine or mutate an imported binding with define, define-syntax or set!. However, a REPL should permit these actions. Does it mean that redefining is only an error when it does happen in libraries for imported bindings? I understand that it prohibits optimisations by compilers if the compiler does not know whether, say + still means the built-in addition or is any other user-specified error. But from this perspective, it does not make sense to restrict forbidding to rebind on the library level, when it would also make sense (at least) for imported bindings in programs. P.S.: As this is all about the environment of a scheme program: am I right in saying that environments are not first class citizens because one cannot get hold of the current environment? (Which, in turn, allows a compiled program to forget about the chosen names of the bindings.)

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• Does IE completely ignore cache control headers for AJAX requests?

  - by Joshua Hayworth

  Hello there, I've got, what I would consider, a simple test web site. A single page with a single button. Here is a copy of the source I'm working with if you would like to download it and play with it. When that button is clicked, it creates a JavaScript timer that executes once a second. When the timer function is executed, An AJAX call is made to retrieve a text value. That text value is then placed into the DOM. What's my problem? IE Caching. Crack open Task Manager and watch what happens to the iexplorer.exe process (IE 8.0.7600.16385 for me) while the timer in that page is executing. See the memory and handle count getting larger? Why is that happening when, by all accounts, I have caching turned off. I've got the jQuery cache option set to false in $.ajaxSetup. I've got the CacheControl header set to no-cache and no-store. The Expires header is set to DateTime.Now.AddDays(-1). The headers are set in both the page code-behind as well as the HTTP Handler's response. Anybody got any ideas as to how I could prevent IE from caching the results of the AJAX call? Here is what the iexplorer.exe process looks like in ProcessMonitor. I believe that the activity shown in this picture is exactly what I'm attempting to prevent.

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• Prevent hash navigation url

  - by Koningh

  I have the following problem: I'm using a slider (coda) to let people navigate trough some 'pages'. The slider uses hash links to navigate to the next page/slide. If a user is at page one (#page1), there is a link which will lead the user to page 2 (#page2) and so on. At the top of the slider the numbers of the pages appear as a link, but only when the page is visited. So if there are six pages and the user navigates from the first to the second and then the third one, there are only three links at the top of the slider (to page one, two and three). The problem is that a user can navigate to page five (or any page actually) without first visiting the pages previous to page five by just using the hash URL and typing the whole link in their address bar. For example if I would type www.mydomain.com/slider/index.php#page5 the slider automatically navigates to the fifth slide/page of the slider and thereby skipping the first four. I want to allow users to navigate to #page5 only if they have visited the first four (So by clicking trough the slides). This means that if they would go to #page5 directly by typing the URL in the address bar, I would like them to be send to the first page (#page1). Does anyone have any idea on solving this?

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• trouble with state monad composition

  - by user1308560

  I was trying out the example given at http://www.haskell.org/haskellwiki/State_Monad#Complete_and_Concrete_Example_1 How this makes the solution composible is beyond my understanding. Here is what I tried but I get compile errors as follows: Couldn't match expected type `GameValue -> StateT GameState Data.Functor.Identity.Identity b0' with actual type `State GameState GameValue' In the second argument of `(>>=)', namely `g2' In the expression: g1 >>= g2 In an equation for `g3': g3 = g1 >>= g2 Failed, modules loaded: none. Here is the code: See the end lines module StateGame where import Control.Monad.State type GameValue = Int type GameState = (Bool, Int) -- suppose I want to play one game after the other g1 = playGame "abcaaacbbcabbab" g2 = playGame "abcaaacbbcabb" g3 = g1 >>= g2 m2 = print $ evalState g3 startState playGame :: String -> State GameState GameValue playGame [] = do (_, score) <- get return score playGame (x:xs) = do (on, score) <- get case x of 'a' | on -> put (on, score + 1) 'b' | on -> put (on, score - 1) 'c' -> put (not on, score) _ -> put (on, score) playGame xs startState = (False, 0) main str = print $ evalState (playGame str) startState

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• How to iterate properly across a const set?

  - by Jared

  I'm working on a program that's supposed to represent a graph. My issue is in my printAdjacencyList function. Basically, I have a Graph ADT that has a member variable "nodes", which is a map of the nodes of that graph. Each Node has a set of Edge* to the edges it is connected to. I'm trying to iterate across each node in the graph and each edge of a node. void MyGraph::printAdjacencyList() { std::map<std::string, MyNode*>::iterator mit; std::set<MyEdge*>::iterator sit; for (mit = nodes.begin(); mit != nodes.end(); mit++ ) { std::cout << mit->first << ": {"; const std::set<MyEdge*> edges = mit->second->getEdges(); for (sit = edges.begin(); sit != edges.end(); sit++) { std::pair<MyNode*, MyNode*> edgeNodes = *sit->getEndpoints(); } } std::cout << " }" << std::endl; } getEdges is declared as: const std::set<MyEdge*>& getEdges() { return edges; }; and get Endpoints is declared as: const std::pair<MyNode*, MyNode*>& getEndpoints() { return nodes; }; The compiler error I'm getting is: MyGraph.cpp:63: error: request for member `getEndpoints' in `*(&sit)->std::_Rb_tree_const_iterator<_Tp>::operator-> [with _Tp = MyEdge*]()', which is of non-class type `MyEdge* const' MyGraph.cpp:63: warning: unused variable 'edgeNodes' I have figured out that this probably means I'm misusing const somewhere, but I can't figure out where for the life of me. Any information would be appreciated. Thanks!

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• Uniq in awk; removing duplicate values in a column using awk

  - by D W

  I have a large datafile in the following format below: ENST00000371026 WDR78,WDR78,WDR78, WD repeat domain 78 isoform 1,WD repeat domain 78 isoform 1,WD repeat domain 78 isoform 2, ENST00000371023 WDR32 WD repeat domain 32 isoform 2 ENST00000400908 RERE,KIAA0458, atrophin-1 like protein isoform a,Homo sapiens mRNA for KIAA0458 protein, partial cds., The columns are tab separated. Multiple values within columns are comma separated. I would like to remove the duplicate values in the second column to result in something like this: ENST00000371026 WDR78 WD repeat domain 78 isoform 1,WD repeat domain 78 isoform 1,WD repeat domain 78 isoform 2, ENST00000371023 WDR32 WD repeat domain 32 isoform 2 ENST00000400908 RERE,KIAA0458 atrophin-1 like protein isoform a,Homo sapiens mRNA for KIAA0458 protein, partial cds., I tried the following code below but it doesn't seem to remove the duplicate values. awk ' BEGIN { FS="\t" } ; { split($2, valueArray,","); j=0; for (i in valueArray) { if (!( valueArray[i] in duplicateArray)) { duplicateArray[j] = valueArray[i]; j++; } }; printf $1 "\t"; for (j in duplicateArray) { if (duplicateArray[j]) { printf duplicateArray[j] ","; } } printf "\t"; print $3 }' knownGeneFromUCSC.txt How can I remove the duplicates in column 2 correctly?

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• crash when using stl vector at instead of operator[]

  - by Jamie Cook

  I have a method as follows (from a class than implements TBB task interface - not currently multithreading though) My problem is that two ways of accessing a vector are causing quite different behaviour - one works and the other causes the entire program to bomb out quite spectacularly (this is a plugin and normally a crash will be caught by the host - but this one takes out the host program as well! As I said quite spectacular) void PtBranchAndBoundIterationOriginRunner::runOrigin(int origin, int time) const // NOTE: const method { BOOST_FOREACH(int accessMode, m_props->GetAccessModes()) { // get a const reference to appropriate vector from member variable // map<int, vector<double>> m_rowTotalsByAccessMode; const vector<double>& rowTotalsForAccessMode = m_rowTotalsByAccessMode.find(accessMode)->second; if (origin != 129) continue; // Additional debug constrain: I know that the vector only has one non-zero element at index 129 m_job->Write("size: " + ToString(rowTotalsForAccessMode.size())); try { // check for early return... i.e. nothing to do for this origin if (!rowTotalsForAccessMode[origin]) continue; // <- this works if (!rowTotalsForAccessMode.at(origin)) continue; // <- this crashes } catch (...) { m_job->Write("Caught an exception"); // but its not an exception } // do some other stuff } } I hate not putting in well defined questions but at the moment my best phrasing is : "WTF?" I'm compiling this with Intel C++ 11.0.074 [IA-32] using Microsoft (R) Visual Studio Version 9.0.21022.8 and my implementation of vector has const_reference operator[](size_type _Pos) const { // subscript nonmutable sequence #if _HAS_ITERATOR_DEBUGGING if (size() <= _Pos) { _DEBUG_ERROR("vector subscript out of range"); _SCL_SECURE_OUT_OF_RANGE; } #endif /* _HAS_ITERATOR_DEBUGGING */ _SCL_SECURE_VALIDATE_RANGE(_Pos < size()); return (*(_Myfirst + _Pos)); } (Iterator debugging is off - I'm pretty sure) and const_reference at(size_type _Pos) const { // subscript nonmutable sequence with checking if (size() <= _Pos) _Xran(); return (*(begin() + _Pos)); } So the only difference I can see is that at calls begin instead of simply using _Myfirst - but how could that possibly be causing such a huge difference in behaviour?

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• Many users, many cpus, no delays. Good for cloud?

  - by Eric

  I wish to set up a CPU-intensive time-important query service for users on the internet. A usage scenario is described below. Is cloud computing the right way to go for such an implementation? If so, what cloud vendor(s) cater to this type of application? I ask specifically, in terms of: 1) pricing 2) latency resulting from: - slow CPUs, instance creations, JIT compiles, etc.. - internal management and communication of processes inside the cloud (e.g. a queuing process and a calculation process) - communication between cloud and end user 3) ease of deployment A usage scenario I am expecting is: - A typical user sends a query (XML of size around 1K) once every 30 seconds on average. - Each query requires a numerical computation of average time 0.2 sec and max time 1 sec on a 1 GHz Pentium. The computation requires no data other than the query itself and is performed by the same piece of code each time. - The delay a user experiences between sending a query and receiving a response should be on average no more than 2 seconds and in general no more than 5 seconds. - A background save to a DB of the response should occur (not time critical) - There can be up to 30000 simultaneous users - i.e., on average 1000 queries a second, each requiring an average 0.2 sec calculation, so that would necessitate around 200 CPUs. Currently I'm look at GAE Java (for quicker deployment and less IT hassle) and EC2 (Speed and price optimization) as options. Where can I learn more about the right way to set ups such a system? past threads, different blogs, books, etc.. BTW, if my terminology is wrong or confusing, please let me know. I'd greatly appreciate any help.

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• Getting memory leak at NSURL connection in Iphone sdk.

  - by monish

  Hi guys, Here Im getting leak at the NSURL connection in my libxml parser can anyone tell how to resolve it. The code where leak generates is: - (BOOL)parseWithLibXML2Parser { BOOL success = NO; ZohoAppDelegate *appDelegate = (ZohoAppDelegate*) [ [UIApplication sharedApplication] delegate]; NSString* curl; if ([cName length] == 0) { curl = @"https://invoice.zoho.com/api/view/settings/currencies?ticket="; curl = [curl stringByAppendingString:appDelegate.ticket]; curl = [curl stringByAppendingString:@"&apikey="]; curl = [curl stringByAppendingString:appDelegate.apiKey]; curl = [curl stringByReplacingOccurrencesOfString:@"\n" withString:@""]; } NSURLRequest *theRequest = [NSURLRequest requestWithURL:[NSURL URLWithString:curl]]; NSLog(@"the request parserWithLibXml2Parser %@",theRequest); NSURLConnection *con = [[[NSURLConnection alloc] initWithRequest:theRequest delegate:self] autorelease];//Memory leak generated here at this line of code. //self.connection = con; //[con release]; // This creates a context for "push" parsing in which chunks of data that are // not "well balanced" can be passed to the context for streaming parsing. // The handler structure defined above will be used for all the parsing. The // second argument, self, will be passed as user data to each of the SAX // handlers. The last three arguments are left blank to avoid creating a tree // in memory. _xmlParserContext = xmlCreatePushParserCtxt(&simpleSAXHandlerStruct, self, NULL, 0, NULL); if(con != nil) { do { [[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode beforeDate:[NSDate distantFuture]]; } while (!_done && !self.error); } if(self.error) { //NSLog(@"parsing error"); [self.delegate parser:self encounteredError:nil]; } else { success = YES; } return success; } Anyone's help will be muck appreciated . Thank you, Monish.

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• Determing if an unordered vector<T> has all unique elements

  - by Hooked

  Profiling my cpu-bound code has suggested I that spend a long time checking to see if a container contains completely unique elements. Assuming that I have some large container of unsorted elements (with < and = defined), I have two ideas on how this might be done: The first using a set: template <class T> bool is_unique(vector<T> X) { set<T> Y(X.begin(), X.end()); return X.size() == Y.size(); } The second looping over the elements: template <class T> bool is_unique2(vector<T> X) { typename vector<T>::iterator i,j; for(i=X.begin();i!=X.end();++i) { for(j=i+1;j!=X.end();++j) { if(*i == *j) return 0; } } return 1; } I've tested them the best I can, and from what I can gather from reading the documentation about STL, the answer is (as usual), it depends. I think that in the first case, if all the elements are unique it is very quick, but if there is a large degeneracy the operation seems to take O(N^2) time. For the nested iterator approach the opposite seems to be true, it is lighting fast if X[0]==X[1] but takes (understandably) O(N^2) time if all the elements are unique. Is there a better way to do this, perhaps a STL algorithm built for this very purpose? If not, are there any suggestions eek out a bit more efficiency?

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• Jquery passing an HTML element into a function

  - by christian

  I have an HTML form where I am going to copy values from a series of input fields to some spans/headings as the user populates the input fields. I am able to get this working using the following code: $('#source').keyup(function(){ if($("#source").val().length == 0){ $("#destinationTitle").text('Sample Title'); }else{ $("#destinationTitle").text($("#source").val()); } }); In the above scenario the html is something like: Sample Title Basically, as the users fills out the source box, the text of the is changed to the value of the source input. If nothing is input in, or the user deletes the values typed into the box some default text is placed in the instead. Pretty straightforward. However, since I need to make this work for many different fields, it makes sense to turn this into a generic function and then bind that function to each 's onkeyup() event. But I am having some trouble with this. My implementation: function doStuff(source,target,defaultValue) { if($(source).val().length == 0){ $(target).text(defaultValue); }else{ $(target).text($(source).val()); } } which is called as follows: $('#source').keyup(function() { doStuff(this, '"#destinationTitle"', 'SampleTitle'); }); What I can't figure out is how to pass the second parameter, the name of the destination html element into the function. I have no problem passing in the element I'm binding to via "this", but can't figure out the destination element syntax. Any help would be appreciated - many thanks!

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• Linear Interpolation. How to implement this algorithm in C ? (Python version is given)

  - by psihodelia

  There exists one very good linear interpolation method. It performs linear interpolation requiring at most one multiply per output sample. I found its description in a third edition of Understanding DSP by Lyons. This method involves a special hold buffer. Given a number of samples to be inserted between any two input samples, it produces output points using linear interpolation. Here, I have rewritten this algorithm using Python: temp1, temp2 = 0, 0 iL = 1.0 / L for i in x: hold = [i-temp1] * L temp1 = i for j in hold: temp2 += j y.append(temp2 *iL) where x contains input samples, L is a number of points to be inserted, y will contain output samples. My question is how to implement such algorithm in ANSI C in a most effective way, e.g. is it possible to avoid the second loop? NOTE: presented Python code is just to understand how this algorithm works. UPDATE: here is an example how it works in Python: x=[] y=[] hold=[] num_points=20 points_inbetween = 2 temp1,temp2=0,0 for i in range(num_points): x.append( sin(i*2.0*pi * 0.1) ) L = points_inbetween iL = 1.0/L for i in x: hold = [i-temp1] * L temp1 = i for j in hold: temp2 += j y.append(temp2 * iL) Let's say x=[.... 10, 20, 30 ....]. Then, if L=1, it will produce [... 10, 15, 20, 25, 30 ...]

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• iPhone: Which are the most useful techniques for faster Bluetooth?

  - by Mike Howard

  Hi. I'm adding peer-to-peer bluetooth using GameKit to an iPhone shoot-em-up, so speed is vital. I'm sending about 40 messages a second each way, most of them with the faster GKSendDataUnreliable, all serializing with NSCoding. In testing between a 3G and 3GS, this is slowing the 3G down a lot more than I'd like. I'm wondering where I should concentrate my efforts to speed it up. How much slower is GKSendDataReliable? For the few packets that have to get there, would it be faster to send a GKSendDataUnreliable and have the peer send an acknowledgement so I can send again if I don't get the Ack within, say, 100ms? How much faster would it be to create the NSData instance using a regular C array rather than archiving with the NSCoding protocol? Is this serialization process (for about a dozen floats) just as slow as you'd expect from an object creation/deallocation overhead, or is something particularly slow happening? I heard that (for example) sending four seperate sets of data is much, much slower, than sending one piece of data four times the size. Would I make a significant saving by sending separate packets of data that wouldn't always go together in the same packet when they happen at the same time? Are there any other bluetooth performance secrets I've missed? Thanks for your help.

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• jquery ui dialog open multiple dialog boxes using the same class on the button and the content div

  - by MichaelAntoni

  Hello there, i want to open multiple dialog boxes by using the same class on both the button and the content div. The below works but only for the first time. jQuery('.helpDialog').hide(); jQuery('.helpButton').click(function() { jQuery(this).next('.helpDialog').dialog({ autoOpen: true, title: 'Help', width: 500, height: 300, position: [180,10], draggable: true, resizable: false, modal: false }); return false; }); we know the reason for this http://blog.nemikor.com/2009/04/08/basic-usage-of-the-jquery-ui-dialog/ "the second call is ignored because the dialog has already been instantiated on that element." But when i fix that problem by trying the code below, the dialog box no longer opens. Can anyone help? Thanks in advance jQuery('.helpDialog').hide(); jQuery(function() { jQuery('.helpDialog').dialog({ autoOpen: false, modal: true, title: 'Info', width: 600, height: 400, position: [200,0], draggable: false }); }); jQuery('.helpButton').click(function() { jQuery(this).next('.helpDialog').dialog('open'); return false; });

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• C# Freq. Table with Random Values

  - by Sef

  Hello, I am trying to write a frequency program that will represent a bar diagram (in console code). The problem is i have no idea how exactly to caculate this frequency or how do i exactly then give the bars different heights according to there frequency (trough calculation). The frequency height is capped at 21. (meaning the bars go from 1 to 21, so the max bar height would be for example 21 stars(* as display sign for the bar itself). A calculation i have so far (although not sure if correct) for frequency: This array takes the random values generated: for (int j = 0; j < T.Length; j++) { T[j] = (MaxHeight* T[j]) / Ber.GreatestElement(T); Console.Write("{0,7}", T[j]); } This results in values between 0 and 21 -- Based on the values my bars should give a certain height compared to all the other frequency values. (for example 8000 could have 21 in height where 39 could have 1). To represent this diagram i used 2 for loops to display height and width (keep in mind i only wish to use Using System; to keep it to the "basics"). for (int height= 1; height<= 21; height++) { for (int width= 0; width<= 10; width++) { if(...??) { Console.Write("{0,7}", bar); // string bar= ("*"); } else { Console.Write("{0,7}", empty); } } Console.WriteLine(); } So so far i have a entire field filled with * and the random values generated along with their frequency value (although i have no idea if the freq value is properly calculated). I assume i need a if (.....) in the second for but i cannot seem to get further then this. Thanks in advance!

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• Java: Inputting text from a file using split

  - by 00PS

  I am inputting an adjacency list for a graph. There are three columns of data (vertex, destination, edge) separated by a single space. Here is my implementation so far: FileStream in = new FileStream("input1.txt"); Scanner s = new Scanner(in); String buffer; String [] line = null; while (s.hasNext()) { buffer = s.nextLine(); line = buffer.split("\\s+"); g.add(line[0]); System.out.println("Added vertex " + line[0] + "."); g.addEdge(line[0], line[1], Integer.parseInt(line[2])); System.out.println("Added edge from " + line[0] + " to " + line[1] + " with a weight of " + Integer.parseInt(line[2]) + "."); } System.out.println("Size of graph = " + g.size()); Here is the output: Added vertex a. Added edge from a to b with a weight of 9. Exception in thread "main" java.lang.NullPointerException at structure5.GraphListDirected.addEdge(GraphListDirected.java:93) at Driver.main(Driver.java:28) I was under the impression that line = buffer.split("\\s+"); would return a 2 dimensional array of Strings to the variable line. It seemed to work the first time but not the second. Any thoughts? I would also like some feedback on my implementation of this problem. Is there a better way? Anything to help out a novice! :)

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• Vertical line on HxW canvas of pixels

  - by bobby williams

  I searched and found nothing. I'm trying to draw lines (simple y=mx+b ones) on a canvas of black pixels. It works fine, but no line occurs when it is vertical. I'm not sure why. My first if statement checks if the denominator is zero, therefore m is undefined and no need for a line equation. My second and third if statement check how steep it is and based on that, calculate the points in between. I don't think there is a need for other classes, since I think there is a bug in my code or I'm just not translating the mathematics into code properly. If more is needed, I'll be happy to post more. /** * Returns an collection of points that connects p1 and p2 */ public ArrayList getPoints() { ArrayList points = new ArrayList(); // checks to see if denominator in m is zero. if zero, undefined. if ((p2.getX() - p1.getX()) == 0) { for (int y = p1.getY(); y<p2.getY(); y++) { points.add(new Point(p1.getX(), y, getColor())); } } double m = (double)(p2.getY()-p1.getY())/(double)(p2.getX()-p1.getX()); int b = (int)(p1.getY() - (m * p1.getX())); // checks to see if slope is steep. if (m > -1 || m < 1) { for (int x = p1.getX(); x<p2.getX(); x++) { int y = (int) ((m*x)+b); points.add(new Point(x, y, getColor())); } } // checks to see if slope is not steep. if (m <= -1 || m >= 1) { for (int y = p1.getY(); y<p2.getY(); y++) { int x = (int) ((y-b)/m); points.add(new Point(x, y, getColor())); } } return points; }

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• What's the best practice for handling system-specific information under version control?

  - by Joe

  I'm new to version control, so I apologize if there is a well-known solution to this. For this problem in particular, I'm using git, but I'm curious about how to deal with this for all version control systems. I'm developing a web application on a development server. I have defined the absolute path name to the web application (not the document root) in two places. On the production server, this path is different. I'm confused about how to deal with this. I could either: Reconfigure the development server to share the same path as the production Edit the two occurrences each time production is updated. I don't like #1 because I'd rather keep the application flexible for any future changes. I don't like #2 because if I start developing on a second development server with a third path, I would have to change this for every commit and update. What is the best way to handle this? I thought of: Using custom keywords and variable expansion (such as setting the property $PATH$ in the version control properties and having it expanded in all the files). Git doesn't support this because it would be a huge performance hit. Using post-update and pre-commit hooks. Possibly the likely solution for git, but every time I looked at the status, it would report the two files as being changed. Not really clean. Pulling the path from a config file outside of version control. Then I would have to have the config file in the same location on all servers. Might as well just have the same path to begin with. Is there an easy way to deal with this? Am I over thinking it?

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• Creating simple calculator with bison & flex in C++ (not C)

  - by ak91

  Hey, I would like to create simple C++ calculator using bison and flex. Please note I'm new to the creating parsers. I already found few examples in bison/flex but they were all written in C. My goal is to create C++ code, where classes would contain nodes of values, operations, funcs - to create AST (evaluation would be done just after creating whole AST - starting from the root and going forward). For example: my_var = sqrt(9 ** 2 - 32) + 4 - 20 / 5 my_var * 3 Would be parsed as: = / \ my_var + / \ sqrt - | / \ - 4 / / \ / \ ** 32 20 5 / \ 9 2 and the second AST would look like: * / \ my_var 3 Then following pseudocode reflects AST: ast_root = create_node('=', new_variable("my_var"), exp) where exp is: exp = create_node(OPERATOR, val1, val2) but NOT like this: $$ = $1 OPERATOR $3 because this way I directly get value of operation instead of creation the Node. I believe the Node should contain type (of operation), val1 (Node), val2 (Node). In some cases val2 would be NULL, like above mentioned sqrt which takes in the end one argument. Right? It will be nice if you can propose me C++ skeleton (without evaluation) for above described problem (including *.y file creating AST) to help me understand the way of creating/holding Nodes in AST. Code can be snipped, just to let me get the idea. I'll also be grateful if you point me to an existing (possibly simple) example if you know any. Thank you all for your time and assistance!

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• rendering a TextView in a Bitmap for an android widget

  - by foke

  I'm building a widget which displays some text. By widget I mean the kind which lies on the desktop. The problem is that I want to change text's font at runtime. There is several textview I would like, at runtime, to set the first as bold, the second blue and italic for example, etc. I came up with this : TextView tv = new TextView(context); tv.setText(stringToDisplay); tv.setTextColor(0xa00050ff); // example tv.setTextSize(30); // example Bitmap b = loadBitmapFromView(tv); updateViews.setImageViewBitmap(R.id.id_of_the_imageview, b); with private static Bitmap loadBitmapFromView(View v) { Bitmap b = Bitmap.createBitmap(v.getLayoutParams().width, v.getLayoutParams().height, Bitmap.Config.ARGB_8888); Canvas c = new Canvas(b); v.layout(0, 0, v.getLayoutParams().width, v.getLayoutParams().height); v.draw(c); return b; } but it wont work (NullPointerException on first line of loadBitmap), until I replace v.getLayoutParams().width, v.getLayoutParams().height by fixed sizes like 250, 50 Bitmap b = Bitmap.createBitmap(250, 50, Bitmap.Config.ARGB_8888); // ... v.layout(0, 0, 250, 50); But that's not a good solution ... so I tried this : LayoutInflater li = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE); View row = li.inflate(R.layout.widget_text, null); TextView tv = (TextView) row.findViewById(R.id.id_of_the_textview); widget_text being a layout similar to the displayed one but with TextViews instead of ImageViews, in the hope to get some size information out of it .. but it's not working and I get this exception : 01-02 17:35:06.001: ERROR/AndroidRuntime(11025): Caused by: java.lang.IllegalArgumentException: width and height must be > 0 on the call to Bitmap.createBitmap() so, someone could point me in the right direction?

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• codeigniter differentiate field names in JOINed tables

  - by Patrick

  Hi, I need to retrieve data from two tables. the first is a list of events, the second is a list of venues. I have a fields with the same name in both tables: events.venue (which is an ID) and venues.venue is the name of the place, say "blues bar". The tables can be joined on events.venue = venues.id. Snippet of my model: $this->db->select('events.*, venues.*'); $this->db->join('venues', 'events.venue = venues.id'); if ($date != 'all') { $this->db->where('date', $date); } if ($keyword) { $this->db->like('description', $keyword); $this->db->or_like('band', $keyword); $this->db->or_like('venue', $keyword); $this->db->or_like('genre', $keyword); } $Q = $this->db->get('events'); if ($Q->num_rows() > 0) { foreach ($Q->result() as $row) { $data[] = $row; } } $Q->free_result(); return $data; Snippet of the View: foreach ($events as $row) { echo "<p>{$row->band} ({$row->genre})<br />"; echo "Playing at: {$row->venue}<br /></p>"; // echoes "blues bar" //more here... } 2 Questions: 1) Why does $row-venue echo venues.venue, instead of events.venue? B) how can I differentiate them? eg. What if I want to echo both events.venue and venues.venue? I can probably do something like "SELECT venues.venue as name_of_the_venue", but how can I do this when I've already selected *?

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• Using boost::iterator_adaptor

  - by Neil G

  I wrote a sparse vector class (see #1, #2.) I would like to provide two kinds of iterators: The first set, the regular iterators, can point any element, whether set or unset. If they are read from, they return either the set value or value_type(), if they are written to, they create the element and return the lvalue reference. Thus, they are: Random Access Traversal Iterator and Readable and Writable Iterator The second set, the sparse iterators, iterate over only the set elements. Since they don't need to lazily create elements that are written to, they are: Random Access Traversal Iterator and Readable and Writable and Lvalue Iterator I also need const versions of both, which are not writable. I can fill in the blanks, but not sure how to use boost::iterator_adaptor to start out. Here's what I have so far: class iterator : public boost::iterator_adaptor< iterator // Derived , value_type* // Base , boost::use_default // Value , boost::?????? // CategoryOrTraversal > class sparse_iterator : public boost::iterator_adaptor< iterator // Derived , value_type* // Base , boost::use_default // Value , boost::random_access_traversal_tag? // CategoryOrTraversal >

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• ViewController behaving oddly when pushed on the window

  - by ayazalavi

  I am using multiple controller during launch of an application in app delegate. One controller is for registration and the second controller is tabbar. tabbar was loading fine but when I pushed registration controller on window, contents went up by 20 units and I have good white blank screen at bottom. Therefore I recreated frame of my registration view controller in its viewdidload method and slided it 20 units down. The code is self.view.frame = CGRectMake(0, 20, self.view.frame.size.width, self.view.frame.size.height); and code in my app delegate for launch application was - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { if (![self accountExists]) { //code if account does not exists on iphone app database self.registerAccount = [[registerViewController alloc] initWithNibName:@"registerViewController" bundle:nil]; [window addSubview:registerAccount.view]; } else if([self autoLoginForAnyAccount]){ //code for autologin to app } else { self.tabBarController.selectedIndex = 1; self.tabBarController.delegate = self; [window addSubview:tabBarController.view]; } [window makeKeyAndVisible]; return YES; } if anyone knows why there is a white space at bottom when registration controller is pushed then please share it with me.

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• Doing some downloading without blocking you app

  - by Code

  Hi guys, I'm working on my first app that's doing a few different web connections at once. My first screen is my Menu. And at the bottom of viewDidLoad of MenuViewController i call a method that gets and parses a .xml file that is located on my webserver. Also at the bottom of viewDidLoad i do FootballScores = [[FootBallScores alloc] init]; and FootballScores makes a connection to a html page which it loads into a string and then parses out data. Now since both of these are getting called at the bottom of viewDidLoad of the class thats is responsible for the main menu(first screen in the app) it means the app is kinda slow to load. What is the right way to do the above? Should i remove the 2 pieces of code from my viewDidLoad and replace with maybe dataGetterOne = [NSTimer scheduledTimerWithTimeInterval:1.000 target:self selector:@selector(xmlParser) userInfo:nil repeats:NO]; dataGetterTwo = [NSTimer scheduledTimerWithTimeInterval:2.000 target:self selector:@selector(htmlParser) userInfo:nil repeats:NO]; This would mean that the methods get called later on and the viewDidLoad gets to finish before the i try get the data from the web servers. Making 2 connections to we bservers a second apart to quick? Can the iphone handle having 2 connections open at once? I'm really unsure of anything bad/dangerous I am doing in regards to connections. Many Thanks -Code

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• Jquery UI dialog does not disappear

  - by iamrohitbanga

  I am using jquery-ui tabs and dialog functionality. Each tab has a button on the page which opens a dialog. This works for one of the tabs. However if I go the second tab, the button does not work there. When I come back to the first tab, the dialog does show up but the problem is I notice as I make switches back and forth to the first tab, it keeps on inserting new div's while the old div's have display:none set on them. I am doing this using JSP. This is how the reusable jsp looks like: <script> $(function() { var formData = null; $.ajax({ url : "addFormGenerator.html", success : function(data) { formData = data; $("#addFormDialog").html(data); $("#addFormDialog").dialog({ autoOpen : false, height : 300, width : 350, modal : true, buttons : { "Add" : function() { $(this).dialog("close"); }, Cancel : function() { $(this).dialog("close"); } }, close : function() { } }); } }); $("#addButton").button().click(function() { $("#addFormDialog").html(formData); $("#addFormDialog").dialog("open"); }); }); </script> <button id="addButton">Click here to Add New</button> <div id="addFormDialog" title="Add New"></div> This jsp fragment is included in other jsp pages as well. I was assuming as I switch between tabs the old button will be garbage collected. Can you help me understand the problem and fix it?

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