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• Pre-formatting text to prevent reflowing

  - by mattjn

  I've written a fairly simple script that will take elements (in this case, <p> elements are the main concern) and type their contents out like a typewriter, one by one. The problem is that as it types, when it reaches the edge of the container mid-word, it reflows the text and jumps to the next line (like word wrap in any text editor). This is, of course, expected behavior; however, I would like to pre-format the text so that this does not happen. I figure that inserting <br> before the word that will wrap would be the best solution, but I'm not quite sure what the best way to go about doing that is that supports all font sizes and container widths, while also keeping any HTML tags intact. I figure something involving a hidden <span> element, adding text to it gradually and checking its width against the container width might be on the right track, but I'm not quite sure how to actually put this together. Any help or suggestions on better methods would be appreciated.

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• PHP Outputting File Attachments with Headers

  - by OneNerd

  After reading a few posts here I formulated this function which is sort of a mishmash of a bunch of others: function outputFile( $filePath, $fileName, $mimeType = '' ) { // Setup $mimeTypes = array( 'pdf' => 'application/pdf', 'txt' => 'text/plain', 'html' => 'text/html', 'exe' => 'application/octet-stream', 'zip' => 'application/zip', 'doc' => 'application/msword', 'xls' => 'application/vnd.ms-excel', 'ppt' => 'application/vnd.ms-powerpoint', 'gif' => 'image/gif', 'png' => 'image/png', 'jpeg' => 'image/jpg', 'jpg' => 'image/jpg', 'php' => 'text/plain' ); // Send Headers //-- next line fixed as per suggestion -- header('Content-Type: ' . $mimeTypes[$mimeType]); header('Content-Disposition: attachment; filename="' . $fileName . '"'); header('Content-Transfer-Encoding: binary'); header('Accept-Ranges: bytes'); header('Cache-Control: private'); header('Pragma: private'); header('Expires: Mon, 26 Jul 1997 05:00:00 GMT'); readfile($filePath); } I have a php page (file.php) which does something like this (lots of other code stripped out): // I run this thru a safe function not shown here $safe_filename = $_GET['filename']; outputFile ( "/the/file/path/{$safe_filename}", $safe_filename, substr($safe_filename, -3) ); Seems like it should work, and it almost does, but I am having the following issues: When its a text file, I am getting a strange symbol as the first letter in the text document When its a word doc, it is corrupt (presumably that same first bit or byte throwing things off). I presume all other file types will be corrupt - have not even tried them Any ideas on what I am doing wrong? Thanks - UPDATE: changed line of code as suggested - still same issue.

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• Survey statistic diagram ideas

  - by Nort

  Hey everyone, I've got some homework tasks in topic surveys and diagrams. The first task is to normalize the input of a survey, because the structure of the data is changing from time-to-time. So there are three types of surveys: static fields, where text is stored dynamic ones, where the user can select one option and multiselect fields, where the user can select multiple options So I'm not really a statistics guy, so I have really no idea what I can do with that incomming data. So the data I have is stored in an orbital XML file from there I can easily get how man times a survey was filled, and how many times a field was filled, so I can (for eg on a pie chart show the relation of filled or not filled). The second idea is to show the relation between the content of a multi option element using a bar chart or so. In case of the multi option elements I've got the idea to show data in implication of one option. But the question is, what could be shown? The other problem are the static elements (text fields and so). What data could be represented from a single field? The data in the XML field is collected from 2001 to 2005 So maybe I can work with the dates of the surveys, but as I said, i don't really know how to process the data, to collect as much data as possible.

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• Appropriate uses of Monad `fail` vs. MonadPlus `mzero`

  - by jberryman

  This is a question that has come up several times for me in the design code, especially libraries. There seems to be some interest in it so I thought it might make a good community wiki. The fail method in Monad is considered by some to be a wart; a somewhat arbitrary addition to the class that does not come from the original category theory. But of course in the current state of things, many Monad types have logical and useful fail instances. The MonadPlus class is a sub-class of Monad that provides an mzero method which logically encapsulates the idea of failure in a monad. So a library designer who wants to write some monadic code that does some sort of failure handling can choose to make his code use the fail method in Monad or restrict his code to the MonadPlus class, just so that he can feel good about using mzero, even though he doesn't care about the monoidal combining mplus operation at all. Some discussions on this subject are in this wiki page about proposals to reform the MonadPlus class. So I guess I have one specific question: What monad instances, if any, have a natural fail method, but cannot be instances of MonadPlus because they have no logical implementation for mplus? But I'm mostly interested in a discussion about this subject. Thanks! EDIT: One final thought occured to me. I recently learned (even though it's right there in the docs for fail) that monadic "do" notation is desugared in such a way that pattern match failures, as in (x:xs) <- return [] call the monad's fail. It seems like the language designers must have been strongly influenced by the prospect of some automatic failure handling built in to haskell's syntax in their inclusion of fail in Monad.

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• "Most popular" GROUP BY in LINQ?

  - by tags2k

  Assuming a table of tags like the stackoverflow question tags: TagID (bigint), QuestionID (bigint), Tag (varchar) What is the most efficient way to get the 25 most used tags using LINQ? In SQL, a simple GROUP BY will do: SELECT Tag, COUNT(Tag) FROM Tags GROUP BY Tag I've written some LINQ that works: var groups = from t in DataContext.Tags group t by t.Tag into g select new { Tag = g.Key, Frequency = g.Count() }; return groups.OrderByDescending(g => g.Frequency).Take(25); Like, really? Isn't this mega-verbose? The sad thing is that I'm doing this to save a massive number of queries, as my Tag objects already contain a Frequency property that would otherwise need to check back with the database for every Tag if I actually used the property. So I then parse these anonymous types back into Tag objects: groups.OrderByDescending(g => g.Frequency).Take(25).ToList().ForEach(t => tags.Add(new Tag() { Tag = t.Tag, Frequency = t.Frequency })); I'm a LINQ newbie, and this doesn't seem right. Please show me how it's really done.

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• Why does this Haskell code produce the "infinite type" error?

  - by Charlie Flowers

  I am new to Haskell and facing a "cannot construct infinite type" error that I cannot make sense of. In fact, beyond that, I have not been able to find a good explanation of what this error even means, so if you could go beyond my basic question and explain the "infinite type" error, I'd really appreciate it. Here's the code: intersperse :: a -> [[a]] -> [a] -- intersperse '*' ["foo","bar","baz","quux"] -- should produce the following: -- "foo*bar*baz*quux" -- intersperse -99 [ [1,2,3],[4,5,6],[7,8,9]] -- should produce the following: -- [1,2,3,-99,4,5,6,-99,7,8,9] intersperse _ [] = [] intersperse _ [x] = x intersperse s (x:y:xs) = x:s:y:intersperse s xs And here's the error trying to load it into the interpreter: Prelude :load ./chapter.3.ending.real.world.haskell.exercises.hs [1 of 1] Compiling Main ( chapter.3.ending.real.world.haskell.exercises.hs, interpreted ) chapter.3.ending.real.world.haskell.exercises.hs:147:0: Occurs check: cannot construct the infinite type: a = [a] When generalising the type(s) for `intersperse' Failed, modules loaded: none. Thanks. EDIT: Thanks to the responses, I have corrected the code and I also have a general guideline for dealing with the "infinite type" error in Haskell: Corrected code intersperse _ [] = [] intersperse _ [x] = x intersperse s (x:xs) = x ++ s:intersperse s xs What the problem was: My type signature states that the second parameter to intersperse is a list of lists. Therefore, when I pattern matched against "s (x:y:xs)", x and y became lists. And yet I was treating x and y as elements, not lists. Guideline for dealing with the "infinite type" error: Most of the time, when you get this error, you have forgotten the types of the various variables you're dealing with, and you have attempted to use a variable as if it were some other type than what it is. Look carefully at what type everything is versus how you're using it, and this will usually uncover the problem.

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• How can I build a generic dataset-handling Perl library?

  - by Pep.

  Hello, I want to build a generic Perl module for handling and analysing biomedical character separated datasets and which can, most certain, be used on any kind of datasets that contain a mixture of categorical (A,B,C,..) and continuous (1.2,3,881..) and identifier (XXX1,XXX2...). The plan is to have people initialize the module and then use some arguments to point to the data file(s), the place were the analysis reports should be placed and the structure of the data. By structure of data I mean which variable is in which place and its name/type. And this is where I need some enlightenment. I am baffled how to do this in a clean way. Obviously, having people create a simple schema file, be it XML or some other format would be the cleanest but maybe not all people enjoy doing something like this. The solutions I can think of are: Create a configuration file in XML or similar and with a prespecified format. Pass the information during initialization of the module. Use the first row of the data as headers and try to guess types (ouch) Surely there must be a "canonical" way of doing this that is also usable and efficient. Thanks p.

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• Delphi: How to avoid EIntOverflow underflow when subtracting?

  - by Ian Boyd

  Microsoft already says, in the documentation for GetTickCount, that you could never compare tick counts to check if an interval has passed. e.g.: Incorrect (pseudo-code): DWORD endTime = GetTickCount + 10000; //10 s from now ... if (GetTickCount > endTime) break; The above code is bad because it is suceptable to rollover of the tick counter. For example, assume that the clock is near the end of it's range: endTime = 0xfffffe00 + 10000 = 0x00002510; //9,488 decimal Then you perform your check: if (GetTickCount > endTime) Which is satisfied immediatly, since GetTickCount is larger than endTime: if (0xfffffe01 > 0x00002510) The solution Instead you should always subtract the two time intervals: DWORD startTime = GetTickCount; ... if (GetTickCount - startTime) > 10000 //if it's been 10 seconds break; Looking at the same math: if (GetTickCount - startTime) > 10000 if (0xfffffe01 - 0xfffffe00) > 10000 if (1 > 10000) Which is all well and good in C/C++, where the compiler behaves a certain way. But what about Delphi? But when i perform the same math in Delphi, with overflow checking on ({Q+}, {$OVERFLOWCHECKS ON}), the subtraction of the two tick counts generates an EIntOverflow exception when the TickCount rolls over: if (0x00000100 - 0xffffff00) > 10000 0x00000100 - 0xffffff00 = 0x00000200 What is the intended solution for this problem? Edit: i've tried to temporarily turn off OVERFLOWCHECKS: {$OVERFLOWCHECKS OFF}] delta = GetTickCount - startTime; {$OVERFLOWCHECKS ON} But the subtraction still throws an EIntOverflow exception. Is there a better solution, involving casts and larger intermediate variable types?

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• Pass an array from IronRuby to C#

  - by cgyDeveloper

  I'm sure this is an easy fix and I just can't find it, but here goes: I have a C# class (let's call it Test) in an assembly (let's say SOTest.dll). Here is something along the lines of what I'm doing: private List<string> items; public List<string> list_items() { return this.items; } public void set_items(List<string> new_items) { this.items = new_items; } In the IronRuby interpreter I run: >>> require "SOTest.dll" true >>> include TestNamespace Object >>> myClass = Test.new TestNamespace.Test >>> myClass.list_items() ['Apples', 'Oranges', 'Pears'] >>> myClass.set_items ['Peaches', 'Plums'] TypeError: can't convert Array into System::Collections::Generic::List(string) I get a similar error whether I make the argument a 'List< string ', 'List< object ' or 'string[ ]'. What is the proper syntax? I can't find a documented mapping of types anywhere (because it's likely too complicated to define in certain scenarios given what Ruby can do).

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• How do I select dynamic ids in this format?

  - by sjsc

  I'm trying to select dynamic ids when a user types something into the input fields. My app spits out the input fields in the following format: <input id="student_1_first_name" /> <input id="student_1_last_name" /> <input id="student_2_first_name" /> <input id="student_2_last_name" /> <input id="student_3_first_name" /> <input id="student_3_last_name" /> etc. For example, I tried doing this to select the end of the id string: <script type="text/javascript"> $(document).ready( function (){ $("input[id$=_first_name]").bind("keyup", run_some_function_here); run_some_function_here(); $("input[id$=_last_name]").bind("keyup", run_some_function_here); run_some_function_here(); } ); </script> When I do that, Jquery can't seem to select the input ids, so the functions don't run. Do you have any ideas on how I can select the ids correctly?

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• Starting an STA thread, but with parameters to the final function

  - by DRapp

  I'm a bit weak on how some delegates behave, such as passing a method as the parameter to be invoked. While trying to do some NUnit test scripts, I have something that I need to run many test with. Each of these tests requires a GUI created and thus the need for an STA thread. So, I have something like public class MyTest { // the Delegate "ThreadStart" is part of the System.Threading namespace and is defined as // public delegate void ThreadStart(); protected void Start_STA_Thread(ThreadStart whichMethod) { Thread thread = new Thread(whichMethod); thread.SetApartmentState(ApartmentState.STA); //Set the thread to STA thread.Start(); thread.Join(); } [Test] public void Test101() { // Since the thread issues an INVOKE of a method, I'm having it call the // corresponding "FromSTAThread" method, such as Start_STA_Thread( Test101FromSTAThread ); } protected void Test101FromSTAThread() { MySTA_RequiredClass oTmp = new MySTA_RequiredClass(); Assert.IsTrue( oTmp.DoSomething() ); } } This part all works fine... Now the next step. I now have a different set of tests that ALSO require an STA thread. However, each "thing" I need to do requires two parameters... both strings (for this case). How do I go about declaring proper delegate so I can pass in the method I need to invoke, AND the two string parameters in one shot... I may have 20+ tests to run with in this pattern and may have future of other similar tests with different parameter counts and types of parameters too. Thanks.

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• MySQL - What is wrong with this query or my database? Terrible performance.

  - by Moss

  SELECT * from `employees` a LEFT JOIN (SELECT phone1 p1, count(*) c, FROM `employees` GROUP BY phone1) b ON a.phone1 = b.p1; I'm not sure if it is this query in particular that has the problem. I have been getting terrible performance in general with this database. The table in question has 120,000 rows. I have tried this particular query remotely and locally with the MyISAM and InnoDB engines, with different types of joins, and with and without an index on phone1. I can get this to complete in about 4 minutes on a 10,000 row table successfully but performance drops exponentially with larger tables. Remotely it will lose connection to the server and locally it brings my system to its knees and seems to go on forever. This query is only a smaller step I was trying to do when a larger query couldn't complete. Maybe I should explain the whole scenario. I have one big flat ugly table that lists a bunch of people and their contact info and the info of the companies they work for. I'm trying to normalize the database and intelligently determine which phone numbers apply to individual people and which apply to an office location. My reasoning is that if a phone number occurs multiple times and the number of occurrence equals the number of times that the street address it is attached to occurs then it must be an office number. So the first step is to count each phone number grouping by phone number. Normally if you just use COUNT()...GROUP BY it will only list the first record it finds in that group so I figured I have to join the full table to the count table where the phone number matches. This does work but as I said I can't successfully complete it on any table much larger than 10,000 rows. This seems pathetic and this doesn't seem like a crazy query to do. Is there a better way to achieve what I want or do I have to break my large table into 12 pieces or is there something wrong with the table or db?

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• Automatically restarting Erlang applications

  - by Nick

  I recently ran into a bug where an entire Erlang application died, yielding a log message that looked like this: =INFO REPORT==== 11-Jun-2010::11:07:25 === application: myapp exited: shutdown type: temporary I have no idea what triggered this shutdown, but the real problem I have is that it didn't restart itself. Instead, the now-empty Erlang VM just sat there doing nothing. Now, from the research I've done, it looks like there are other "start types" you can give an application: 'transient' and 'permanent'. If I start a Supervisor within an application, I can tell it to make a particular process transient or permanent, and it will automatically restart it for me. However, according to the documentation, if I make an application transient or permanent, it doesn't restart it when it dies, but rather it kills all the other applications as well. What I really want to do is somehow tell the Erlang VM that a particular application should always be running, and if it goes down, restart it. Is this possible to do? (I'm not talking about implementing a supervisor on top of my application, because then it's a catch 22: what if my supervisor process crashes? I'm looking for some sort of API or setting that I can use to have Erlang monitor and restart my application for me.) Thanks!

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• How to hide helper functions from public API in c

  - by emge

  I'm working on a project and I need to create an API. I am using sockets to communicate between the server (my application) and the clients (the other applications using my API). This project is in c not C++ I come from a linux background and this is my first project using Windows, Visual Studio 2008, and dll libraries. I have communication working between the client and server, but I have some that is duplicated on both projects. I would like to create a library (probably a dll file), that both projects can link to so I don't have to maintain extra code. I also have to create the library that has the API that I need to make available for my clients. Within the API functions that I want public are the calls to these helper functions that are "duplicated code", I don't want to expose these functions to my client, but I do want my server to be able to use those functions. How can I do this? I will try to clarify with an example. This is what I started with. Server Project: int Server_GetPacket(SOCKET sd); int ReceiveAll(SOCKET sd, char *buf, int len); int VerifyLen(char *buf); Client Project: int Client_SendCommand(int command); int Client_GetData(int command, char *buf, int len); int ReceiveAll(SOCKET sd, char *buf, int len); int VerifyLen(char *buf); This is kind of what I would like to end up with: //Server Project: int Server_GetPacket(SOCKET sd); // library with public and private types // private API (not exposed to my client) int ReceiveAll(SOCKET sd, char *buf, int len); int VerifyLen(char *buf); // public API (header file available for client) int Client_SendCommand(int command); int Client_GetData(int command, char *buf, int len); Thanks any help would be appreciated.

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• C++ Templates: Convincing self against code bloat

  - by ArunSaha

  I have heard about code bloats in context of C++ templates. I know that is not the case with modern C++ compilers. But, I want to construct an example and convince myself. Lets say we have a class template< typename T, size_t N > class Array { public: T * data(); private: T elems_[ N }; }; template< typename T, size_t N > T * Array<T>::data() { return elems_; } Further, let's say types.h contains typedef Array< int, 100 > MyArray; x.cpp contains MyArray ArrayX; and y.cpp contains MyArray ArrayY; Now, how can I verify that the code space for MyArray::data() is same for both ArrayX and ArrayY? What else I should know and verify from this (or other similar simple) examples? If there is any g++ specific tips, I am interested for that too. PS: Regarding bloat, I am concerned even for the slightest of bloats, since I come from embedded context.

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• C# wrapper for objects

  - by Haggai

  I'm looking for a way to create a generic wrapper for any object. The wrapper object will behave just like the class it wraps, but will be able to have more properties, variable, methods etc., for e.g. object counting, caching etc. Say the wrapper class be called Wrapper, and the class to be wrapped be called Square and has the constructor Square(double edge_len) and the properties/methods EdgeLength and Area, I would like to use it as follows: Wrapper<Square> mySquare = new Wrapper<Square>(2.5); /* or */ new Square(2.5); Console.Write("Edge {0} -> Area {1}", mySquare.EdgeLength, mySquare.Area); Obviously I can create such a wrapper class for each class I want to wrap, but I'm looking for a general solution, i.e. Wrapper<T> which can handle both primitive and compound types (although in my current situation I would be happy with just wrapping my own classes). Suggestions? Thanks.

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• Casting Type array to Generic array?

  - by George R

  The short version of the question - why can't I do this? I'm restricted to .NET 3.5. T[] genericArray; // Obviously T should be float! genericArray = new T[3]{ 1.0f, 2.0f, 0.0f }; // Can't do this either, why the hell not genericArray = new float[3]{ 1.0f, 2.0f, 0.0f }; Longer version - I'm working with the Unity engine here, although that's not important. What is - I'm trying to throw conversion between its fixed Vector2 (2 floats) and Vector3 (3 floats) and my generic Vector< class. I can't cast types directly to a generic array. using UnityEngine; public struct Vector { private readonly T[] _axes; #region Constructors public Vector(int axisCount) { this._axes = new T[axisCount]; } public Vector(T x, T y) { this._axes = new T[2] { x, y }; } public Vector(T x, T y, T z) { this._axes = new T[3]{x, y, z}; } public Vector(Vector2 vector2) { // This doesn't work this._axes = new T[2] { vector2.x, vector2.y }; } public Vector(Vector3 vector3) { // Nor does this this._axes = new T[3] { vector3.x, vector3.y, vector3.z }; } #endregion #region Properties public T this[int i] { get { return _axes[i]; } set { _axes[i] = value; } } public T X { get { return _axes[0];} set { _axes[0] = value; } } public T Y { get { return _axes[1]; } set { _axes[1] = value; } } public T Z { get { return this._axes.Length (Vector2 vector2) { Vector vector = new Vector(vector2); return vector; } public static explicit operator Vector(Vector3 vector3) { Vector vector = new Vector(vector3); return vector; } #endregion }

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• JPA entitylisteners and @embeddable

  - by seanizer

  I have a class hierarchy of JPA entities that all inherit from a BaseEntity class: @MappedSuperclass @EntityListeners( { ValidatorListener.class }) public abstract class BaseEntity implements Serializable { // other stuff } I want all entities that implement a given interface to be validated automatically on persist and/or update. Here's what I've got. My ValidatorListener: public class ValidatorListener { private enum Type { PERSIST, UPDATE } @PrePersist public void checkPersist(final Object entity) { if (entity instanceof Validateable) { this.check((Validateable) entity, Type.PERSIST); } } @PreUpdate public void checkUpdate(final Object entity) { if (entity instanceof Validateable) { this.check((Validateable) entity, Type.UPDATE); } } private void check(final Validateable entity, final Type persist) { switch (persist) { case PERSIST: if (entity instanceof Persist) { ((Persist) entity).persist(); } if (entity instanceof PersistOrUpdate) { ((PersistOrUpdate) entity).persistOrUpdate(); } break; case UPDATE: if (entity instanceof Update) { ((Update) entity).update(); } if (entity instanceof PersistOrUpdate) { ((PersistOrUpdate) entity).persistOrUpdate(); } break; default: break; } } } and here's my Validateable interface that it checks against (the outer interface is just a marker, the inner contain the methods): public interface Validateable { interface Persist extends Validateable { void persist(); } interface PersistOrUpdate extends Validateable { void persistOrUpdate(); } interface Update extends Validateable { void update(); } } All of this works, however I would like to extend this behavior to Embeddable classes. I know two solutions: call the validation method of the embeddable object manually from the entity validation method: public void persistOrUpdate(){ // validate my own properties first // then manually validate the embeddable property: myEmbeddable.persistOrUpdate(); // this works but I'd like something that I don't have to call manually } use reflection, checking all properties to see if their type is of one of their interface types. This would work, but it's not pretty. Is there a more elegant solution?

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• Selectind DOM elements based on attribute content

  - by sameold

  I have several types of <a> in my document. I'd like to select only the <a> whose title attribute begins with the text "more data ..." like <a title="more data *"> For example given the markup below, I'd like to select the first and second <a>, but skip the third because title doesn't begin with more data, and skip the 4th because <a> doesn't even have a title attribute. <a title="more data some text" href="http://mypage.com/page.html">More</a> <a title="more data other text" href="http://mypage.com/page.html">More</a> <a title="not needed" href="http://mypage.com/page.html">Not needed</a> <a href="http://mypage.com/page.html">Not needed</a> I'm using DOMXPath. How would my query look like? $xpath = new DOMXPath($doc); $q = $xpath->query('//a');

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• Surely a foolish error, but I can't see it

  - by dnagirl

  I have a form (greatly simplified): <form action='http://example.com/' method='post' name='event_form'> <input type='text' name='foo' value='3'/> <input type='submit' name='event_submit' value='Edit'/> </form> And I have a class "EventForm" to process the form. The main method, process() looks like this: public function process($submitname=false){ $success=false; if ($submitname && isset($_POST[$submitname])){ //PROBLEM: isset($_POST[$submitname] is always FALSE for some reason if($success=$this->ruler->validate()){//check that dependancies are honoured and data types are correct if($success=$this->map_fields()){//divide input data into Event, Schedule_Element and Temporal_Expression(s) $success=$this->eventholder->save(); } } } else {//get the record from the db based on event_id or schedule_element_id foreach($this->gets as $var){//list of acceptable $_GET keys if(isset($_GET[$var])){ if($success= $this->__set($var,$_GET[$var])) break; } } } $this->action=(empty($this->eventholder->event_id))? ADD : EDIT; return $success; } When the form is submitted, this happens: $form->process('event_submit'); For some reason though, isset($_POST['event_submit']) always evaluates to FALSE. Can anyone see why?

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• Open closed prinicple, problem

  - by Marcus

  Hi, I'm trying to apply OCP to a code snippet I have that in it's current state is really smelly, but I feel I'm not getting all the way to the end. Current code: public abstract class SomeObject {} public class SpecificObject1 : SomeObject {} public class SpecificObject2 : SomeObject {} // Smelly code public class Model { public void Store(SomeObject someObject) { if (someObject is SpecificObject1) {} else if (someObject is SpecificObject2) {} } } That is really ugly, my new approach looks like this: // No so smelly code public class Model { public void Store(SomeObject someObject) { throw new Expception("Not allowed!"); } public void Store(SpecificObject1 someObject) {} public void Store(SpecificObject2 someObject) {} } When a new SomeObject type comes along I must implement how that specific object is stored, this will break OCP cause I need to alter the Model-class. To move the store logic to SomeObject also feels wrong cause then I will violate SRP (?), becuase in this case the SomeObject is almost like a DTO, it's resposibility it not how to know to store itself. If a new implementation to SomeObject comes along who's store implementation is missing I will get a runtime error due to exception in Store method in Model class, it also feels like a code smell. This is because calling code will in the form of IEnumerable<SomeObject> sequence; I will not know the specific types of the sequence objects. I can't seem to grasp the OCP-concept. Anyone has any concrete examples or links that is a bit more than just some Car/Fruit example?

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• Solr : how do i index and search several fields?

  - by sbrattla

  Hi, I've set up my first 'installation' of Solr, where each index (document) represents a musical work (with properties like number (int), title (string), version (string), composers (string) and keywords (string)). I've set the field 'title' as the default search field. However, what do I do when I would like to do a query on all fields? I'd like to give users the opportunity to search in all fields, and as far as I've understood there is at least two options for this: (1) Specify which fields the query should be made against. (2) Set up the Solr configuration with copyfields, so that values added to each of the fields will be copied to a 'catch-all'-like field which can be used for searching. However, in this case, i am uncertain how things would turn out when i take into consideration that the data types are not all the same for the various fields (the various fields will to a lesser og greater degree go through filters, but as copyfield values are taken from their original fields before the values have been run through their original fields' filters, i would have to apply one single filter to all values on the copyfield. This, again, would result in integers being 'filtered' just as strings would). Is this a case where i should use copyfields? At first glance, it seems a bit more 'flexible' to rather just search on all fields. However, maybe there's a cost? All feedback appreciated! Thanks!

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• C: socket connection timeout

  - by The.Anti.9

  I have a simple program to check if a port is open, but I want to shorten the timeout length on the socket connection because the default is far too long. I'm not sure how to do this though. Here's the code: #include <sys/socket.h> #include <sys/time.h> #include <sys/types.h> #include <arpa/inet.h> #include <netinet/in.h> #include <errno.h> #include <fcntl.h> #include <stdio.h> #include <netdb.h> #include <stdlib.h> #include <string.h> #include <unistd.h> int main(int argc, char **argv) { u_short port; /* user specified port number */ char addr[1023]; /* will be a copy of the address entered by u */ struct sockaddr_in address; /* the libc network address data structure */ short int sock = -1; /* file descriptor for the network socket */ if (argc != 3) { fprintf(stderr, "Usage %s <port_num> <address>", argv[0]); return EXIT_FAILURE; } address.sin_addr.s_addr = inet_addr(argv[2]); /* assign the address */ address.sin_port = htons(atoi(argv[2])); /* translate int2port num */ sock = socket(AF_INET, SOCK_STREAM, 0); if (connect(sock,(struct sockaddr *)&address,sizeof(address)) == 0) { printf("%i is open\n", port); } close(sock); return 0; }

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• Input questions mysql php html

  - by Marcelo

  (Q1)Hi I'm using textbox in my project and I can't receive the values that are typed <textarea rows="5" cols="60"> Type your suggestion </textarea> <br> <input type="submit" name="sugestao" value="Submit" /> Sorry I don't know how to 'kill' html code, that's why < is missing. All I'm getting in the column of the database from this text box is "Submit", I'd like to receive whatever is written in the text area. How can I make the value equal whaterever is typed? (Q2) How can I make sure that I'll only store the same type(int,varchar,text) that I setted,declared in the database. For example: age(int), but if someone types "abc" in the input it will be stored in my database as the value 0 . How can I forbid this, and only save the age when it's just int and all the other fields(like name, email) are filled ?. And if is still possible warn the user that he is typing something wrong, don't need to say where. Sorry for any mistake in English and Thanks for the attention.

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• C# - Calling ToString() on a Reference Type

  - by nfplee

  Given two object arrays I need to compare the differences between the two (when converted to a string). I've reduced the code to the following and the problem still exists: public void Compare(object[] array1, object[] array2) { for (var i = 0; i < array1.Length; i++) { var value1 = GetStringValue(array1[i]); var value2 = GetStringValue(array2[i]); } } public string GetStringValue(object value) { return value != null && value.ToString() != string.Empty ? value.ToString() : ""; } The code executes fine no matter what object arrays I throw at it. However if one of the items in the array is a reference type then somehow the reference is updated. This causes issues later. It appears that this happens when calling ToString() against the object reference. I have updated the GetStringValue method to the following (which makes sure the object is either a value type or string) and the problem goes away. public string GetStringValue(object value) { return value != null && (value.GetType().IsValueType || value is string) && value.ToString() != string.Empty ? value.ToString() : ""; } However this is just a temporary hack as I'd like to be able to override the ToString() method on my reference types and compare them as well. I'd appreciate it if someone could explain why this is happening and offer a potential solution. Thanks

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