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  • TakeWhile and SkipWhile method in LINQ

    - by vik20000in
     In my last post I talked about how to use the take and the Skip keyword to filter out the number of records that we are fetching. But there is only problem with the take and skip statement. The problem lies in the dependency where by the number of records to be fetched has to be passed to it. Many a times the number of records to be fetched is also based on the query itself. For example if we want to continue fetching records till a certain condition is met on the record set. Let’s say we want to fetch records from the array of number till we get 7. For this kind of query LINQ has exposed the TakeWhile Method.     int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };     var firstNumbersLessThan6 = numbers.TakeWhile(n => n < 7);   In the same way we can also use the SkipWhile statement. The skip while statement will skip all the records that do not match certain condition provided. In the example below we are skiping all those number which are not divisible by 3. Remember we could have done this with where clause also, but SkipWhile method can be useful in many other situation and hence the example and the keyword.     int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };     var allButFirst3Numbers = numbers.SkipWhile(n => n % 3 != 0); Vikram

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  • How to have an improved relationship with recruiters?

    - by crosenblum
    I personally, always have problems with recruiter's and their constant spam.. I usually get tons of emails for jobs, not related to what I do. Or they have no idea what I do. Or they say they have a job in my field, but make me go thru hours of paperwork, only to find out they had no real job lead. Or my resume contained a keyword, that they searched for, but that keyword is like 1-10% of what I do, not my main job skill set. My point being is that I want to have a more polite, more accurate, less waste of each other's time. So I want to come up with a form letter, I can create in gmail to automatically send to all recruiter's, to help inform, educate and train them to deal better with me. That way, they know exactly what to send to me, so as to not waste my time. We don't play email/phone tag, just to find out they have no idea what I do, or how to find a job lead that matches that. I want this to be an improvement in my relationship and experience with recruiters, because honestly most of them waste my time. They call me at work, not considering I can't take phone call's at work, and they already had my email address. Mostly they annoy me, but I am tired of having to be rude to get my point across. I want them to immediately make sure they know what I can and have done, (Have you read my resume?) and have actual leads ready to be hired/interviewed soon or now. Any suggestions to how to improve the communication, to avoid wasting each other's time. I certainly hate having to come across as rude or improper, but when they just waste so much of my time, I don't know what else to do. So thank you for your time. Just to be clear, I want your help to write a form letter, that I can send to every recruiter that email's me, how to best work with me, and other people in IT/Web careers.

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  • Finding links among many written and spoken thoughts

    - by Peter Fren
    So... I am using a digital voice recorder to record anything I see important, ranging from business to private, from rants to new business ideas. Every finalized idea is one wma-file. I wrote a program to sort the wma-files into folders. From time to time I listen to the wma-files, convert them to text(manually) and insert them into a mindmap with mindmanager, which I sort hierarchically by area and type in turn. This works very well, no idea is being lost, when I am out of ideas for a special topic, I listen to what I said and can get started again. What could a search system look like that finds links between thoughts(written in the mindmap and in the wma files) or in general gives me good search results even when the keyword I searched for is not present but a synonym of it or related topic(for instance flower should output entries containing orchid aswell, even if they contain orchid but not the very keyword flower). I prefer something ready-made but small adjustments to a given system are fine aswell. How would you approach this task?

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  • Parallelize incremental processing in Tabular #ssas #tabular

    - by Marco Russo (SQLBI)
    I recently came in a problem trying to improve the parallelism of Tabular processing. As you know, multiple tables can be processed in parallel, whereas the processing of several partitions within the same table cannot be parallelized. When you perform an incremental update by adding only new rows to existing table, what you really do is adding rows to a partition, so adding rows to many tables means adding rows to several partitions. The particular condition you have in this case is that every partition in which you add rows belongs to a different table. Adding rows implies using the ProcessAdd command; its QueryBinding parameter specifies a SQL syntax to read new rows, otherwise the original query specified for the partition will be used, and it could generate duplicated data if you don’t have a dynamic behavior on the SQL side. If you create the required XMLA code manually, you will find that the QueryBinding node that should be part of the ProcessAdd command has to be moved out from ProcessAdd in case you are using a Batch command with more than one Process command (which is the reason why you want to use a single batch: run multiple process operations in parallel!). If you use AMO (Analysis Management Objects) you will find that this combination is not supported, even if you don’t have a syntax error compiling the code, but you might obtain this error at execution time: The syntax for the 'Process' command is incorrect. The 'Bindings' keyword cannot appear under a 'Process' command if the 'Process' command is a part of a 'Batch' command and there are more than one 'Process' commands in the 'Batch' or the 'Batch' command contains any out of line related information. In this case, the 'Bindings' keyword should be a part of the 'Batch' command only. If this is happening to you, the best solution I’ve found is manipulating the XMLA code generated by AMO moving the Binding nodes in the right place. A more detailed description of the issue and the code required to send a correct XMLA batch to Analysis Services is available in my article Parallelize ProcessAdd with AMO. By the way, the same technique (and code) can be used also if you have the same problem in a Multidimensional model.

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  • Dealing with curly brace soup

    - by Cyborgx37
    I've programmed in both C# and VB.NET for years, but primarily in VB. I'm making a career shift toward C# and, overall, I like C# better. One issue I'm having, though, is curly brace soup. In VB, each structure keyword has a matching close keyword, for example: Namespace ... Class ... Function ... For ... Using ... If ... ... End If If ... ... End If End Using Next End Function End Class End Namespace The same code written in C# ends up very hard to read: namespace ... { class ... { function ... { for ... { using ... { if ... { ... } if ... { ... } } } // wait... what level is this? } } } Being so used to VB, I'm wondering if there's a technique employed by c-style programmers to improve readability and to ensure that your code ends up in the correct "block". The above example is relatively easy to read, but sometimes at the end of a piece of code I'll have 8 or more levels of curly braces, requiring me to scroll up several pages to figure out which brace ends the block I'm interested in.

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  • Changing website Url - Am I making an SEO mistake

    - by Denis
    I have a webiste with a .com domain that is a year old. The business is a shop based in Ireland and I have purchased a .ie domain. I plan to move the website over to the new domain, SEO Good or Bad idea? Old Url - SmythsOfTerenure.com | New Url - SmythsComputerRepair.ie (I am using Fake names and fictional business in the example Url's) The new domain has my main keyword in it. The old domain has my family name and business location (city district) It currently ranks high for lots of relevant keywords in Google with low traffic and low competition. Current website traffic is about 80 session per week. 80% of that traffic is Organic from Google. I am changing domain in an attempt to help SEO long term by having a CC TLD (.ie rather than .com) and having my main Keyword in the domain. I plan to do 301 re-directs from old to new and update GW Tools and G Analytics but am I making a mistake changing it at all as I know rankings may fall in the sort term. Homepage PR=0 and very few inbound links. Should I just leave it on the old domain? Or after a few months should I be back up ranking as well as I am now?

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  • Sitecore Item Web API and Json.Net Test Drive (Part II –Strongly Typed)

    - by jonel
    In the earlier post I did related to this topic, I have talked about using Json.Net to consume the result of Sitecore Item Web API. In that post, I have used the keyword dynamic to express my intention of consuming the returned json of the API. In this article, I will create some useful classes to write our implementation of consuming the API using strongly-typed. We will start of with the Record class which will hold the top most elements the API will present us. Pretty straight forward class. It has 2 properties to hold the statuscode and the result elements. If you intend to use a different property name in your class from the json property, you can do so by passing a string literal of the json property name to the JsonProperty attribute and name your class property differently. If you look at the earlier post, you will notice that the API returns an array of items that contains all of the Sitecore content item or items and stores them under the result->items array element. To be able to map that array of items, we have to write a collection property and decorate that with the JsonProperty attribute. The JsonItem class is a simple class which will map to the corresponding item property contained in the array. If you notice, these properties are just the basic Sitecore fields. And here’s the main portion of this post that will binds them all together. And here’s the output of this code. In closing, the same result can be achieved using the dynamic keyword or defining classes to map the json propery returned by the Sitecore Item Web API. With a little bit more of coding, you can take advantage of power of strongly-typed solution. Have a good week ahead of you.

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  • What are some practical uses of the "new" modifier in C# with respect to hiding?

    - by Joel Etherton
    A co-worker and I were looking at the behavior of the new keyword in C# as it applies to the concept of hiding. From the documentation: Use the new modifier to explicitly hide a member inherited from a base class. To hide an inherited member, declare it in the derived class using the same name, and modify it with the new modifier. We've read the documentation, and we understand what it basically does and how it does it. What we couldn't really get a handle on is why you would need to do it in the first place. The modifier has been there since 2003, and we've both been working with .Net for longer than that and it's never come up. When would this behavior be necessary in a practical sense (e.g.: as applied to a business case)? Is this a feature that has outlived its usefulness or is what it does simply uncommon enough in what we do (specifically we do web forms and MVC applications and some small factor WinForms and WPF)? In trying this keyword out and playing with it we found some behaviors that it allows that seem a little hazardous if misused. This sounds a little open-ended, but we're looking for a specific use case that can be applied to a business application that finds this particular tool useful.

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  • Multiple domains for different products?

    - by alexandertr
    I have a website with software applications. Is it good for SEO to choose one keyword rich domain name for each of our software products or should we stick to a single domain? From a user's perspective I think it would be easier to remember a domain that is keyword rich as the user will instantly know what this product is for. But I have read articles that the latest trend in SEO is to stick to one domain for all of your products and invest on this single domain website. Is that true? What do you advise? Should I register a separate domain for each of our products or should I use only one single domain? Should I do a 301 redirect with a .htaccess to a single domain? And what about the sitemaps? Should I register all sites in Google Webmaster Tools and post a separate sitemap for each one of them? should my main site sitemap include all pages or should separate domains have their own sitemaps?

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  • How to simulate browser form POST method using PHP/cURL

    - by user283266
    I'm trying to simulate browser with POST method using PHP/cURL. When I looked at that live Http header it shows Content-Type: multipart/form-data. I checked on the internet where it was suggested that cURL will send multipart/form-data when a custom headers is specified to Content-Type: multipart/form-data. $headers = array( 'Content-Type' => 'multipart/form-data; boundary='.$boundary ); This didn't work for me either when I print_r(curl_getinfo()) it showed [content_type] => text/html; charset=UTF-8 Which means cURL sent a default headers I also read that sending/uploading a file with cURL will cause data to be send as multipart/form-data. I created a file which curl uploaded but again when I ran curl_getinfo I got [content_type] => text/html; charset=UTF-8 $data_array = array("field" => "@c:\file_location.txt"); I also tried to read a file content so that the only thing sent would be content NOT ATTACHED FILE but this didn't work for me curl_getinfo shows [content_type] => text/html; charset=UTF-8. $data_array = array("field" => "<c:\file_location.txt"); // note @ replaced with < Do I miss somthing here? This is the referer url POST somepath HTTP/1.1 Host: www(dot)domain(dot)com User-Agent: Mozilla/5.0 (Windows) Gecko/13081217 Firefox/3 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 Accept-Language: en-us,en;q=0.5 Accept-Encoding: gzip,deflate Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7 Keep-Alive: 300 Connection: keep-alive Referer: url/some-file.php Content-Type: multipart/form-data; boundary=--------------------------$boundary Content-Length: $some_number ----------------------------$boundary Content-Disposition: form-data; name="$some_Value1" $some_text1 ----------------------------$boundary Content-Disposition: form-data; name="$some_Value2" $some_text2 ----------------------------$boundary Content-Disposition: form-data; name="$some_Value3" $some_text3 ----------------------------$boundary Content-Disposition: form-data; name="$some_Value4" $some_text4 ----------------------------$boundary Content-Disposition: form-data; name="$some_Value5" $some_text5 ----------------------------$boundary Content-Disposition: form-data; name="$some_Value6" $some_text6 ----------------------------$boundary Content-Disposition: form-data; name="$some_Value7" $some_text7 ----------------------------$boundary Content-Disposition: form-data; name="$some_Value8" $some_text8 ----------------------------$boundary Content-Disposition: form-data; name="$some_Value9" ----------------------------$boundary Content-Disposition: form-data; name="$some_Value10" ----------------------------$boundary-- Here is a piece of code. <? //Include files set_time_limit(0); include'body.php'; include'keyword.php'; include'bio.php'; include'summary.php'; include'headline.php'; include'category.php'; include'spin.php'; include'random-text.php'; $category = category(); $headline = headline() ; $summary = summary(); $keyword = keyword(); $body = body(); $bio = bio(); $target="url"; $ref ="url_ref"; $c = "Content-Disposition: form-data; name="; $boundary = "---------------------------".random_text(); $category = category(); $headline = headline() ; $summary = summary(); $keyword = keyword(); $body = body(); $bio = bio(); // emulating content form as it appears on livehttp header $data = "\r\n".$boundary."\r\n".$c."\"pen_id\"\r\n\r\n".$Auth_id."\r\n".$boundary."\r\n".$c."\"cat_id\"\r\n\r\n".category()."\r\n".$boundary."\r\n".$c."\"title\"\r\n\r\n".headline()."\r\n".$boundary."\r\n".$c."\"meta_desc\"\r\n\r\n".summary()."\r\n".$boundary."\r\n".$c."\"meta_keys\"\r\n\r\n".keyword()."\r\n".$boundary."\r\n".$c."\"content\"\r\n\r\n".body()."\r\n".$boundary."\r\n".$c."\"author_bio\"\r\n\r\n".bio()."\r\n".$boundary."\r\n".$c."\"allow_comments\"\r\n\r\ny\r\n".$boundary."\r\n".$c."\"id\"\r\n\r\n\r\n".$boundary."\r\n".$c."\"action\"\r\n\r\n\r\n".$boundary."--\r\n"; // inserting content into a file $file = "C:\file_path.txt"; $fh = fopen($file, 'w+') or die("Can't open file"); fwrite($fh,$data); fclose($fh); // pulling out content from a file as multipart/form-data $data_array = array ("field" => "<C:\file_path.txt"); $headers = array ( 'POST /myhome/article/new HTTP/1.1', 'Host: url', 'User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.20) Gecko/20081217 Firefox/2.0.0.20 (.NET CLR 3.5.30729)', 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9;q=0.8', 'Accept-Language: en-us,en;q=0.5', 'Accept-Encoding: gzip,deflate', 'Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7', 'Keep-Alive: 300', 'Connection: keep-alive', 'Content-Type: multipart/form-data; boundary='.$boundary, 'Content-Length: '.strlen($data), ); # Create the cURL session $ch = curl_init(); curl_setopt($ch, CURLOPT_URL, $target); // Define target site curl_setopt($ch, CURLOPT_POST,1); curl_setopt($ch, CURLOPT_HEADER, $headers); // No http head //curl_setopt($ch, CURLOPT_REFERER, $ref); curl_setopt($ch, CURLOPT_NOBODY, FALSE); curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE); // Return page in string curl_setopt($ch, CURLOPT_COOKIEJAR, "c:\cookie\cookies.txt"); // Tell cURL where to write curl_setopt($ch, CURLOPT_COOKIEFILE, "c:\cookie\cookies.txt"); // Tell cURL which cookies //curl_setopt($ch, CURLOPT_USERAGENT, $agent); curl_setopt($ch, CURLOPT_POST, TRUE); curl_setopt($ch, CURLOPT_POSTFIELDS, "$data_array"); curl_setopt($ch, CURLOPT_FOLLOWLOCATION, TRUE); // Follow redirects curl_setopt($ch, CURLOPT_MAXREDIRS, 4); # Execute the PHP/CURL session and echo the downloaded page $page = curl_exec($ch); $err = curl_error($ch); $info =curl_getinfo($ch); # Close the cURL session curl_close($ch); print_r($err); print_r($info); ?>

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  • Mulit-tenant ASP.NET MVC – Controllers

    - by zowens
    Part I – Introduction Part II – Foundation   The time has come to talk about controllers in a multi-tenant ASP.NET MVC architecture. This is actually the most critical design decision you will make when dealing with multi-tenancy with MVC. In my design, I took into account the design goals I mentioned in the introduction about inversion of control and what a tenant is to my design. Be aware that this is only one way to achieve multi-tenant controllers.   The Premise MvcEx (which is a sample written by Rob Ashton) utilizes dynamic controllers. Essentially a controller is “dynamic” in that multiple action results can be placed in different “controllers” with the same name. This approach is a bit too complicated for my design. I wanted to stick with plain old inheritance when dealing with controllers. The basic premise of my controller design is that my main host defines a set of universal controllers. It is the responsibility of the tenant to decide if the tenant would like to utilize these core controllers. This can be done either by straight usage of the controller or inheritance for extension of the functionality defined by the controller. The controller is resolved by a StructureMap container that is attached to the tenant, as discussed in Part II.   Controller Resolution I have been thinking about two different ways to resolve controllers with StructureMap. One way is to use named instances. This is a really easy way to simply pull the controller right out of the container without a lot of fuss. I ultimately chose not to use this approach. The reason for this decision is to ensure that the controllers are named properly. If a controller has a different named instance that the controller type, then the resolution has a significant disconnect and there are no guarantees. The final approach, the one utilized by the sample, is to simply pull all controller types and correlate the type with a controller name. This has a bit of a application start performance disadvantage, but is significantly more approachable for maintainability. For example, if I wanted to go back and add a “ControllerName” attribute, I would just have to change the ControllerFactory to suit my needs.   The Code The container factory that I have built is actually pretty simple. That’s really all we need. The most significant method is the GetControllersFor method. This method makes the model from the Container and determines all the concrete types for IController.  The thing you might notice is that this doesn’t depend on tenants, but rather containers. You could easily use this controller factory for an application that doesn’t utilize multi-tenancy. public class ContainerControllerFactory : IControllerFactory { private readonly ThreadSafeDictionary<IContainer, IDictionary<string, Type>> typeCache; public ContainerControllerFactory(IContainerResolver resolver) { Ensure.Argument.NotNull(resolver, "resolver"); this.ContainerResolver = resolver; this.typeCache = new ThreadSafeDictionary<IContainer, IDictionary<string, Type>>(); } public IContainerResolver ContainerResolver { get; private set; } public virtual IController CreateController(RequestContext requestContext, string controllerName) { var controllerType = this.GetControllerType(requestContext, controllerName); if (controllerType == null) return null; var controller = this.ContainerResolver.Resolve(requestContext).GetInstance(controllerType) as IController; // ensure the action invoker is a ContainerControllerActionInvoker if (controller != null && controller is Controller && !((controller as Controller).ActionInvoker is ContainerControllerActionInvoker)) (controller as Controller).ActionInvoker = new ContainerControllerActionInvoker(this.ContainerResolver); return controller; } public void ReleaseController(IController controller) { if (controller != null && controller is IDisposable) ((IDisposable)controller).Dispose(); } internal static IEnumerable<Type> GetControllersFor(IContainer container) { Ensure.Argument.NotNull(container); return container.Model.InstancesOf<IController>().Select(x => x.ConcreteType).Distinct(); } protected virtual Type GetControllerType(RequestContext requestContext, string controllerName) { Ensure.Argument.NotNull(requestContext, "requestContext"); Ensure.Argument.NotNullOrEmpty(controllerName, "controllerName"); var container = this.ContainerResolver.Resolve(requestContext); var typeDictionary = this.typeCache.GetOrAdd(container, () => GetControllersFor(container).ToDictionary(x => ControllerFriendlyName(x.Name))); Type found = null; if (typeDictionary.TryGetValue(ControllerFriendlyName(controllerName), out found)) return found; return null; } private static string ControllerFriendlyName(string value) { return (value ?? string.Empty).ToLowerInvariant().Without("controller"); } } One thing to note about my implementation is that we do not use namespaces that can be utilized in the default ASP.NET MVC controller factory. This is something that I don’t use and have no desire to implement and test. The reason I am not using namespaces in this situation is because each tenant has its own namespaces and the routing would not make sense in this case.   Because we are using IoC, dependencies are automatically injected into the constructor. For example, a tenant container could implement it’s own IRepository and a controller could be defined in the “main” project. The IRepository from the tenant would be injected into the main project’s controller. This is quite a useful feature.   Again, the source code is on GitHub here.   Up Next Up next is the view resolution. This is a complicated issue, so be prepared. I hope that you have found this series useful. If you have any questions about my implementation so far, send me an email or DM me on Twitter. I have had a lot of great conversations about multi-tenancy so far and I greatly appreciate the feedback!

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  • Super constructor must be a first statement in Java constructor [closed]

    - by Val
    I know the answer: "we need rules to prevent shooting into your own foot". Ok, I make millions of programming mistakes every day. To be prevented, we need one simple rule: prohibit all JLS and do not use Java. If we explain everything by "not shooting your foot", this is reasonable. But there is not much reason is such reason. When I programmed in Delphy, I always wanted the compiler to check me if I read uninitializable. I have discovered myself that is is stupid to read uncertain variable because it leads unpredictable result and is errorenous obviously. By just looking at the code I could see if there is an error. I wished if compiler could do this job. It is also a reliable signal of programming error if function does not return any value. But I never wanted it do enforce me the super constructor first. Why? You say that constructors just initialize fields. Super fields are derived; extra fields are introduced. From the goal point of view, it does not matter in which order you initialize the variables. I have studied parallel architectures and can say that all the fields can even be assigned in parallel... What? Do you want to use the unitialized fields? Stupid people always want to take away our freedoms and break the JLS rules the God gives to us! Please, policeman, take away that person! Where do I say so? I'm just saying only about initializing/assigning, not using the fields. Java compiler already defends me from the mistake of accessing notinitialized. Some cases sneak but this example shows how this stupid rule does not save us from the read-accessing incompletely initialized in construction: public class BadSuper { String field; public String toString() { return "field = " + field; } public BadSuper(String val) { field = val; // yea, superfirst does not protect from accessing // inconstructed subclass fields. Subclass constr // must be called before super()! System.err.println(this); } } public class BadPost extends BadSuper { Object o; public BadPost(Object o) { super("str"); this. o = o; } public String toString() { // superconstructor will boom here, because o is not initialized! return super.toString() + ", obj = " + o.toString(); } public static void main(String[] args) { new BadSuper("test 1"); new BadPost(new Object()); } } It shows that actually, subfields have to be inilialized before the supreclass! Meantime, java requirement "saves" us from writing specializing the class by specializing what the super constructor argument is, public class MyKryo extends Kryo { class MyClassResolver extends DefaultClassResolver { public Registration register(Registration registration) { System.out.println(MyKryo.this.getDepth()); return super.register(registration); } } MyKryo() { // cannot instantiate MyClassResolver in super super(new MyClassResolver(), new MapReferenceResolver()); } } Try to make it compilable. It is always pain. Especially, when you cannot assign the argument later. Initialization order is not important for initialization in general. I could understand that you should not use super methods before initializing super. But, the requirement for super to be the first statement is different. It only saves you from the code that does useful things simply. I do not see how this adds safety. Actually, safety is degraded because we need to use ugly workarounds. Doing post-initialization, outside the constructors also degrades safety (otherwise, why do we need constructors?) and defeats the java final safety reenforcer. To conclude Reading not initialized is a bug. Initialization order is not important from the computer science point of view. Doing initalization or computations in different order is not a bug. Reenforcing read-access to not initialized is good but compilers fail to detect all such bugs Making super the first does not solve the problem as it "Prevents" shooting into right things but not into the foot It requires to invent workarounds, where, because of complexity of analysis, it is easier to shoot into the foot doing post-initialization outside the constructors degrades safety (otherwise, why do we need constructors?) and that degrade safety by defeating final access modifier When there was java forum alive, java bigots attecked me for these thoughts. Particularly, they dislaked that fields can be initialized in parallel, saying that natural development ensures correctness. When I replied that you could use an advanced engineering to create a human right away, without "developing" any ape first, and it still be an ape, they stopped to listen me. Cos modern technology cannot afford it. Ok, Take something simpler. How do you produce a Renault? Should you construct an Automobile first? No, you start by producing a Renault and, once completed, you'll see that this is an automobile. So, the requirement to produce fields in "natural order" is unnatural. In case of alarmclock or armchair, which are still chair and clock, you may need first develop the base (clock and chair) and then add extra. So, I can have examples where superfields must be initialized first and, oppositely, when they need to be initialized later. The order does not exist in advance. So, the compiler cannot be aware of the proper order. Only programmer/constructor knows is. Compiler should not take more responsibility and enforce the wrong order onto programmer. Saying that I cannot initialize some fields because I did not ininialized the others is like "you cannot initialize the thing because it is not initialized". This is a kind of argument we have. So, to conclude once more, the feature that "protects" me from doing things in simple and right way in order to enforce something that does not add noticeably to the bug elimination at that is a strongly negative thing and it pisses me off, altogether with the all the arguments to support it I've seen so far. It is "a conceptual question about software development" Should there be the requirement to call super() first or not. I do not know. If you do or have an idea, you have place to answer. I think that I have provided enough arguments against this feature. Lets appreciate the ones who benefit form it. Let it just be something more than simple abstract and stupid "write your own language" or "protection" kind of argument. Why do we need it in the language that I am going to develop?

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  • MAMP + Python MySQLDB - trouble installing

    - by Frederico
    I'm currently running the latest version of MAMP on my Snow Leopard OSX, and I'm trying to install MySQLDB. Downloaded: MySQL-python-1.2.3c1 I went into the setup_posix.py and adjusted the location of the mysql_config to the one in MAMP: mysql_config.path = "/Applications/MAMP/Library/bin/mysql_config" When trying to build I get the error below. Could anyone give me a hand please: creating build/temp.macosx-10.6-universal-2.6 gcc-4.2 -fno-strict-aliasing -fno-common -dynamic -DNDEBUG -g -fwrapv -Os -Wall -Wstrict-prototypes -DENABLE_DTRACE -arch i386 -arch ppc -arch x86_64 -pipe -Dversion_info=(1,2,3,'gamma',1) -D_version_=1.2.3c1 -I/Applications/MAMP/Library/include/mysql -I/System/Library/Frameworks/Python.framework/Versions/2.6/include/python2.6 -c _mysql.c -o build/temp.macosx-10.6-universal-2.6/_mysql.o -fno-omit-frame-pointer -D_P1003_1B_VISIBLE -DSIGNAL_WITH_VIO_CLOSE -DSIGNALS_DONT_BREAK_READ -DIGNORE_SIGHUP_SIGQUIT -DDONT_DECLARE_CXA_PURE_VIRTUAL _mysql.c:36:23: error: my_config.h: No such file or directory _mysql.c:38:19: error: mysql.h: No such file or directory _mysql.c:39:26: error: mysqld_error.h: No such file or directory _mysql.c:40:20: error: errmsg.h: No such file or directory _mysql.c:76: error: expected specifier-qualifier-list before ‘MYSQL’ _mysql.c:90: error: expected specifier-qualifier-list before ‘MYSQL_RES’ _mysql.c: In function ‘_mysql_Exception’: _mysql.c:120: warning: implicit declaration of function ‘mysql_errno’ _mysql.c:120: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c:123: error: ‘CR_MAX_ERROR’ undeclared (first use in this function) _mysql.c:123: error: (Each undeclared identifier is reported only once _mysql.c:123: error: for each function it appears in.) _mysql.c:131: error: ‘CR_COMMANDS_OUT_OF_SYNC’ undeclared (first use in this function) _mysql.c:132: error: ‘ER_DB_CREATE_EXISTS’ undeclared (first use in this function) _mysql.c:133: error: ‘ER_SYNTAX_ERROR’ undeclared (first use in this function) _mysql.c:134: error: ‘ER_PARSE_ERROR’ undeclared (first use in this function) _mysql.c:135: error: ‘ER_NO_SUCH_TABLE’ undeclared (first use in this function) _mysql.c:136: error: ‘ER_WRONG_DB_NAME’ undeclared (first use in this function) _mysql.c:137: error: ‘ER_WRONG_TABLE_NAME’ undeclared (first use in this function) _mysql.c:138: error: ‘ER_FIELD_SPECIFIED_TWICE’ undeclared (first use in this function) _mysql.c:139: error: ‘ER_INVALID_GROUP_FUNC_USE’ undeclared (first use in this function) _mysql.c:140: error: ‘ER_UNSUPPORTED_EXTENSION’ undeclared (first use in this function) _mysql.c:141: error: ‘ER_TABLE_MUST_HAVE_COLUMNS’ undeclared (first use in this function) _mysql.c:170: error: ‘ER_DUP_ENTRY’ undeclared (first use in this function) _mysql.c:213: warning: implicit declaration of function ‘mysql_error’ _mysql.c:213: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c:213: warning: passing argument 1 of ‘PyString_FromString’ makes pointer from integer without a cast _mysql.c: In function ‘_mysql_server_init’: _mysql.c:308: warning: label ‘finish’ defined but not used _mysql.c:234: warning: unused variable ‘item’ _mysql.c:233: warning: unused variable ‘groupc’ _mysql.c:233: warning: unused variable ‘i’ _mysql.c:233: warning: unused variable ‘cmd_argc’ _mysql.c:232: warning: unused variable ‘s’ _mysql.c: In function ‘_mysql_ResultObject_Initialize’: _mysql.c:363: error: ‘MYSQL_RES’ undeclared (first use in this function) _mysql.c:363: error: ‘result’ undeclared (first use in this function) _mysql.c:368: error: ‘MYSQL_FIELD’ undeclared (first use in this function) _mysql.c:368: error: ‘fields’ undeclared (first use in this function) _mysql.c:377: error: ‘_mysql_ResultObject’ has no member named ‘use’ _mysql.c:380: warning: implicit declaration of function ‘mysql_use_result’ _mysql.c:380: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c:382: warning: implicit declaration of function ‘mysql_store_result’ _mysql.c:382: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c:383: error: ‘_mysql_ResultObject’ has no member named ‘result’ _mysql.c:386: error: ‘_mysql_ResultObject’ has no member named ‘converter’ _mysql.c:389: warning: implicit declaration of function ‘mysql_num_fields’ _mysql.c:390: error: ‘_mysql_ResultObject’ has no member named ‘nfields’ _mysql.c:391: error: ‘_mysql_ResultObject’ has no member named ‘converter’ _mysql.c:392: warning: implicit declaration of function ‘mysql_fetch_fields’ _mysql.c:438: error: ‘_mysql_ResultObject’ has no member named ‘converter’ _mysql.c: In function ‘_mysql_ResultObject_traverse’: _mysql.c:450: error: ‘_mysql_ResultObject’ has no member named ‘converter’ _mysql.c:451: error: ‘_mysql_ResultObject’ has no member named ‘converter’ _mysql.c: In function ‘_mysql_ResultObject_clear’: _mysql.c:462: error: ‘_mysql_ResultObject’ has no member named ‘converter’ _mysql.c:462: error: ‘_mysql_ResultObject’ has no member named ‘converter’ _mysql.c:462: error: ‘_mysql_ResultObject’ has no member named ‘converter’ _mysql.c:462: error: ‘_mysql_ResultObject’ has no member named ‘converter’ _mysql.c:463: error: ‘_mysql_ResultObject’ has no member named ‘converter’ _mysql.c: In function ‘_mysql_ConnectionObject_Initialize’: _mysql.c:475: error: ‘MYSQL’ undeclared (first use in this function) _mysql.c:475: error: ‘conn’ undeclared (first use in this function) _mysql.c:500: error: ‘_mysql_ConnectionObject’ has no member named ‘converter’ _mysql.c:501: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c:525: error: ‘_mysql_ConnectionObject’ has no member named ‘converter’ _mysql.c:547: warning: implicit declaration of function ‘mysql_init’ _mysql.c:547: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c:550: warning: implicit declaration of function ‘mysql_options’ _mysql.c:550: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c:550: error: ‘MYSQL_OPT_CONNECT_TIMEOUT’ undeclared (first use in this function) _mysql.c:554: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c:554: error: ‘MYSQL_OPT_COMPRESS’ undeclared (first use in this function) _mysql.c:555: error: ‘CLIENT_COMPRESS’ undeclared (first use in this function) _mysql.c:558: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c:558: error: ‘MYSQL_OPT_NAMED_PIPE’ undeclared (first use in this function) _mysql.c:560: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c:560: error: ‘MYSQL_INIT_COMMAND’ undeclared (first use in this function) _mysql.c:562: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c:562: error: ‘MYSQL_READ_DEFAULT_FILE’ undeclared (first use in this function) _mysql.c:564: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c:564: error: ‘MYSQL_READ_DEFAULT_GROUP’ undeclared (first use in this function) _mysql.c:567: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c:567: error: ‘MYSQL_OPT_LOCAL_INFILE’ undeclared (first use in this function) _mysql.c:575: warning: implicit declaration of function ‘mysql_real_connect’ _mysql.c:575: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c:590: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c: In function ‘_mysql_ConnectionObject_traverse’: _mysql.c:671: error: ‘_mysql_ConnectionObject’ has no member named ‘converter’ _mysql.c:672: error: ‘_mysql_ConnectionObject’ has no member named ‘converter’ _mysql.c: In function ‘_mysql_ConnectionObject_clear’: _mysql.c:680: error: ‘_mysql_ConnectionObject’ has no member named ‘converter’ _mysql.c:680: error: ‘_mysql_ConnectionObject’ has no member named ‘converter’ _mysql.c:680: error: ‘_mysql_ConnectionObject’ has no member named ‘converter’ _mysql.c:680: error: ‘_mysql_ConnectionObject’ has no member named ‘converter’ _mysql.c:681: error: ‘_mysql_ConnectionObject’ has no member named ‘converter’ _mysql.c: In function ‘_mysql_ConnectionObject_close’: _mysql.c:696: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c:698: warning: implicit declaration of function ‘mysql_close’ _mysql.c:698: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c:700: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c: In function ‘_mysql_ConnectionObject_affected_rows’: _mysql.c:722: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c:723: warning: implicit declaration of function ‘mysql_affected_rows’ _mysql.c:723: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c: In function ‘_mysql_debug’: _mysql.c:739: warning: implicit declaration of function ‘mysql_debug’ _mysql.c: In function ‘_mysql_ConnectionObject_dump_debug_info’: _mysql.c:757: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c:759: warning: implicit declaration of function ‘mysql_dump_debug_info’ _mysql.c:759: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c: In function ‘_mysql_ConnectionObject_autocommit’: _mysql.c:783: warning: implicit declaration of function ‘mysql_query’ _mysql.c:783: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c: In function ‘_mysql_ConnectionObject_commit’: _mysql.c:806: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c: In function ‘_mysql_ConnectionObject_rollback’: _mysql.c:828: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c: In function ‘_mysql_ConnectionObject_errno’: _mysql.c:940: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c:941: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c: In function ‘_mysql_ConnectionObject_error’: _mysql.c:956: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c:957: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c:957: warning: passing argument 1 of ‘PyString_FromString’ makes pointer from integer without a cast _mysql.c: In function ‘_mysql_escape_string’: _mysql.c:981: warning: implicit declaration of function ‘mysql_escape_string’ _mysql.c: In function ‘_mysql_escape’: _mysql.c:1088: error: ‘_mysql_ConnectionObject’ has no member named ‘converter’ _mysql.c: In function ‘_mysql_ResultObject_describe’: _mysql.c:1168: error: ‘MYSQL_FIELD’ undeclared (first use in this function) _mysql.c:1168: error: ‘fields’ undeclared (first use in this function) _mysql.c:1171: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c:1172: error: ‘_mysql_ResultObject’ has no member named ‘result’ _mysql.c:1173: error: ‘_mysql_ResultObject’ has no member named ‘result’ _mysql.c:1184: warning: implicit declaration of function ‘IS_NOT_NULL’ _mysql.c: In function ‘_mysql_ResultObject_field_flags’: _mysql.c:1204: error: ‘MYSQL_FIELD’ undeclared (first use in this function) _mysql.c:1204: error: ‘fields’ undeclared (first use in this function) _mysql.c:1207: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c:1208: error: ‘_mysql_ResultObject’ has no member named ‘result’ _mysql.c:1209: error: ‘_mysql_ResultObject’ has no member named ‘result’ _mysql.c: At top level: _mysql.c:1250: error: expected declaration specifiers or ‘...’ before ‘MYSQL_ROW’ _mysql.c: In function ‘_mysql_row_to_tuple’: _mysql.c:1256: error: ‘_mysql_ResultObject’ has no member named ‘result’ _mysql.c:1258: warning: implicit declaration of function ‘mysql_fetch_lengths’ _mysql.c:1258: error: ‘_mysql_ResultObject’ has no member named ‘result’ _mysql.c:1258: warning: assignment makes pointer from integer without a cast _mysql.c:1261: error: ‘_mysql_ResultObject’ has no member named ‘converter’ _mysql.c:1262: error: ‘row’ undeclared (first use in this function) _mysql.c: At top level: _mysql.c:1275: error: expected declaration specifiers or ‘...’ before ‘MYSQL_ROW’ _mysql.c: In function ‘_mysql_row_to_dict’: _mysql.c:1280: error: ‘MYSQL_FIELD’ undeclared (first use in this function) _mysql.c:1280: error: ‘fields’ undeclared (first use in this function) _mysql.c:1282: error: ‘_mysql_ResultObject’ has no member named ‘result’ _mysql.c:1284: error: ‘_mysql_ResultObject’ has no member named ‘result’ _mysql.c:1284: warning: assignment makes pointer from integer without a cast _mysql.c:1285: error: ‘_mysql_ResultObject’ has no member named ‘result’ _mysql.c:1288: error: ‘_mysql_ResultObject’ has no member named ‘converter’ _mysql.c:1289: error: ‘row’ undeclared (first use in this function) _mysql.c: At top level: _mysql.c:1314: error: expected declaration specifiers or ‘...’ before ‘MYSQL_ROW’ _mysql.c: In function ‘_mysql_row_to_dict_old’: _mysql.c:1319: error: ‘MYSQL_FIELD’ undeclared (first use in this function) _mysql.c:1319: error: ‘fields’ undeclared (first use in this function) _mysql.c:1321: error: ‘_mysql_ResultObject’ has no member named ‘result’ _mysql.c:1323: error: ‘_mysql_ResultObject’ has no member named ‘result’ _mysql.c:1323: warning: assignment makes pointer from integer without a cast _mysql.c:1324: error: ‘_mysql_ResultObject’ has no member named ‘result’ _mysql.c:1327: error: ‘_mysql_ResultObject’ has no member named ‘converter’ _mysql.c:1328: error: ‘row’ undeclared (first use in this function) _mysql.c: At top level: _mysql.c:1350: error: expected declaration specifiers or ‘...’ before ‘MYSQL_ROW’ _mysql.c: In function ‘mysql_fetch_row’: _mysql.c:1361: error: ‘MYSQL_ROW’ undeclared (first use in this function) _mysql.c:1361: error: expected ‘;’ before ‘row’ _mysql.c:1365: error: ‘_mysql_ResultObject’ has no member named ‘use’ _mysql.c:1366: error: ‘row’ undeclared (first use in this function) _mysql.c:1366: warning: implicit declaration of function ‘mysql_fetch_row’ _mysql.c:1366: error: ‘_mysql_ResultObject’ has no member named ‘result’ _mysql.c:1369: error: ‘_mysql_ResultObject’ has no member named ‘result’ _mysql.c:1372: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c:1380: error: too many arguments to function ‘convert_row’ _mysql.c: In function ‘_mysql_ResultObject_fetch_row’: _mysql.c:1404: error: expected declaration specifiers or ‘...’ before ‘MYSQL_ROW’ _mysql.c:1419: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c:1431: error: ‘_mysql_ResultObject’ has no member named ‘use’ _mysql.c:1445: warning: implicit declaration of function ‘mysql_num_rows’ _mysql.c:1445: error: ‘_mysql_ResultObject’ has no member named ‘result’ _mysql.c: In function ‘_mysql_ConnectionObject_character_set_name’: _mysql.c:1512: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c: In function ‘_mysql_get_client_info’: _mysql.c:1603: warning: implicit declaration of function ‘mysql_get_client_info’ _mysql.c:1603: warning: passing argument 1 of ‘PyString_FromString’ makes pointer from integer without a cast _mysql.c: In function ‘_mysql_ConnectionObject_get_host_info’: _mysql.c:1617: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c:1618: warning: implicit declaration of function ‘mysql_get_host_info’ _mysql.c:1618: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c:1618: warning: passing argument 1 of ‘PyString_FromString’ makes pointer from integer without a cast _mysql.c: In function ‘_mysql_ConnectionObject_get_proto_info’: _mysql.c:1632: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c:1633: warning: implicit declaration of function ‘mysql_get_proto_info’ _mysql.c:1633: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c: In function ‘_mysql_ConnectionObject_get_server_info’: _mysql.c:1647: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c:1648: warning: implicit declaration of function ‘mysql_get_server_info’ _mysql.c:1648: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c:1648: warning: passing argument 1 of ‘PyString_FromString’ makes pointer from integer without a cast _mysql.c: In function ‘_mysql_ConnectionObject_info’: _mysql.c:1664: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c:1665: warning: implicit declaration of function ‘mysql_info’ _mysql.c:1665: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c:1665: warning: assignment makes pointer from integer without a cast _mysql.c: In function ‘_mysql_ConnectionObject_insert_id’: _mysql.c:1697: error: ‘my_ulonglong’ undeclared (first use in this function) _mysql.c:1697: error: expected ‘;’ before ‘r’ _mysql.c:1699: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c:1701: error: ‘r’ undeclared (first use in this function) _mysql.c:1701: warning: implicit declaration of function ‘mysql_insert_id’ _mysql.c:1701: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c: In function ‘_mysql_ConnectionObject_kill’: _mysql.c:1718: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c:1720: warning: implicit declaration of function ‘mysql_kill’ _mysql.c:1720: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c: In function ‘_mysql_ConnectionObject_field_count’: _mysql.c:1739: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c:1741: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c: In function ‘_mysql_ResultObject_num_fields’: _mysql.c:1756: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c:1757: error: ‘_mysql_ResultObject’ has no member named ‘result’ _mysql.c: In function ‘_mysql_ResultObject_num_rows’: _mysql.c:1772: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c:1773: error: ‘_mysql_ResultObject’ has no member named ‘result’ _mysql.c: In function ‘_mysql_ConnectionObject_ping’: _mysql.c:1802: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c:1803: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c:1805: warning: implicit declaration of function ‘mysql_ping’ _mysql.c:1805: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c: In function ‘_mysql_ConnectionObject_query’: _mysql.c:1826: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c:1828: warning: implicit declaration of function ‘mysql_real_query’ _mysql.c:1828: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c: In function ‘_mysql_ConnectionObject_select_db’: _mysql.c:1856: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c:1858: warning: implicit declaration of function ‘mysql_select_db’ _mysql.c:1858: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c: In function ‘_mysql_ConnectionObject_shutdown’: _mysql.c:1877: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c:1879: warning: implicit declaration of function ‘mysql_shutdown’ _mysql.c:1879: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c: In function ‘_mysql_ConnectionObject_stat’: _mysql.c:1904: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c:1906: warning: implicit declaration of function ‘mysql_stat’ _mysql.c:1906: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c:1906: warning: assignment makes pointer from integer without a cast _mysql.c: In function ‘_mysql_ConnectionObject_store_result’: _mysql.c:1927: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c:1928: error: ‘_mysql_ConnectionObject’ has no member named ‘converter’ _mysql.c:1937: error: ‘_mysql_ResultObject’ has no member named ‘result’ _mysql.c: In function ‘_mysql_ConnectionObject_thread_id’: _mysql.c:1966: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c:1968: warning: implicit declaration of function ‘mysql_thread_id’ _mysql.c:1968: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c: In function ‘_mysql_ConnectionObject_use_result’: _mysql.c:1988: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c:1989: error: ‘_mysql_ConnectionObject’ has no member named ‘converter’ _mysql.c:1998: error: ‘_mysql_ResultObject’ has no member named ‘result’ _mysql.c: In function ‘_mysql_ConnectionObject_dealloc’: _mysql.c:2016: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c: In function ‘_mysql_ConnectionObject_repr’: _mysql.c:2028: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c:2029: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c: In function ‘_mysql_ResultObject_data_seek’: _mysql.c:2047: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c:2048: warning: implicit declaration of function ‘mysql_data_seek’ _mysql.c:2048: error: ‘_mysql_ResultObject’ has no member named ‘result’ _mysql.c: In function ‘_mysql_ResultObject_row_seek’: _mysql.c:2061: error: ‘MYSQL_ROW_OFFSET’ undeclared (first use in this function) _mysql.c:2061: error: expected ‘;’ before ‘r’ _mysql.c:2063: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c:2064: error: ‘_mysql_ResultObject’ has no member named ‘use’ _mysql.c:2069: error: ‘r’ undeclared (first use in this function) _mysql.c:2069: warning: implicit declaration of function ‘mysql_row_tell’ _mysql.c:2069: error: ‘_mysql_ResultObject’ has no member named ‘result’ _mysql.c:2070: warning: implicit declaration of function ‘mysql_row_seek’ _mysql.c:2070: error: ‘_mysql_ResultObject’ has no member named ‘result’ _mysql.c: In function ‘_mysql_ResultObject_row_tell’: _mysql.c:2082: error: ‘MYSQL_ROW_OFFSET’ undeclared (first use in this function) _mysql.c:2082: error: expected ‘;’ before ‘r’ _mysql.c:2084: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c:2085: error: ‘_mysql_ResultObject’ has no member named ‘use’ _mysql.c:2090: error: ‘r’ undeclared (first use in this function) _mysql.c:2090: error: ‘_mysql_ResultObject’ has no member named ‘result’ _mysql.c:2091: error: ‘_mysql_ResultObject’ has no member named ‘result’ _mysql.c: In function ‘_mysql_ResultObject_dealloc’: _mysql.c:2099: warning: implicit declaration of function ‘mysql_free_result’ _mysql.c:2099: error: ‘_mysql_ResultObject’ has no member named ‘result’ _mysql.c: At top level: _mysql.c:2330: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c:2337: error: ‘_mysql_ConnectionObject’ has no member named ‘converter’ _mysql.c:2344: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c:2351: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c:2358: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c:2421: error: ‘_mysql_ResultObject’ has no member named ‘converter’ _mysql.c:2421: error: initializer element is not constant _mysql.c:2421: error: (near initialization for ‘_mysql_ResultObject_memberlist[0].offset’) _mysql.c: In function ‘_mysql_ConnectionObject_getattr’: _mysql.c:2443: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c:36:23: error: my_config.h: No such file or directory _mysql.c:38:19: error: mysql.h: No such file or directory _mysql.c:39:26: error: mysqld_error.h: No such file or directory _mysql.c:40:20: error: errmsg.h: No such file or directory _mysql.c:76: error: expected specifier-qualifier-list before ‘MYSQL’ _mysql.c:90: error: expected specifier-qualifier-list before ‘MYSQL_RES’ _mysql.c: In function ‘_mysql_Exception’: _mysql.c:120: warning: implicit declaration of function ‘mysql_errno’ _mysql.c:120: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c:123: error: ‘CR_MAX_ERROR’ undeclared (first use in this function) _mysql.c:123: error: (Each undeclared identifier is reported only once _mysql.c:123: error: for each function it appears in.) _mysql.c:131: error: ‘CR_COMMANDS_OUT_OF_SYNC’ undeclared (first use in this function) _mysql.c:132: error: ‘ER_DB_CREATE_EXISTS’ undeclared (first use in this function) _mysql.c:133: error: ‘ER_SYNTAX_ERROR’ undeclared (first use in this function) _mysql.c:134: error: ‘ER_PARSE_ERROR’ undeclared (first use in this function) _mysql.c:135: error: ‘ER_NO_SUCH_TABLE’ undeclared (first use in this function) _mysql.c:136: error: ‘ER_WRONG_DB_NAME’ undeclared (first use in this function) _mysql.c:137: error: ‘ER_WRONG_TABLE_NAME’ undeclared (first use in this function) _mysql.c:138: error: ‘ER_FIELD_SPECIFIED_TWICE’ undeclared (first use in this function) _mysql.c:139: error: ‘ER_INVALID_GROUP_FUNC_USE’ undeclared (first use in this function) _mysql.c:140: error: ‘ER_UNSUPPORTED_EXTENSION’ undeclared (first use in this function) _mysql.c:141: error: ‘ER_TABLE_MUST_HAVE_COLUMNS’ undeclared (first use in this function) _mysql.c:170: error: ‘ER_DUP_ENTRY’ undeclared (first use in this function) _mysql.c:213: warning: implicit declaration of function ‘mysql_error’ _mysql.c:213: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c:213: warning: passing argument 1 of ‘PyString_FromString’ makes pointer from integer without a cast _mysql.c: In function ‘_mysql_server_init’: _mysql.c:308: warning: label ‘finish’ defined but not used _mysql.c:234: warning: unused variable ‘item’ _mysql.c:233: warning: unused variable ‘groupc’ _mysql.c:233: warning: unused variable ‘i’ _mysql.c:233: warning: unused variable ‘cmd_argc’ _mysql.c:232: warning: unused variable ‘s’ _mysql.c: In function ‘_mysql_ResultObject_Initialize’: _mysql.c:363: error: ‘MYSQL_RES’ undeclared (first use in this function) _mysql.c:363: error: ‘result’ undeclared (first use in this function) _mysql.c:368: error: ‘MYSQL_FIELD’ undeclared (first use in this function) _mysql.c:368: error: ‘fields’ undeclared (first use in this function) _mysql.c:377: error: ‘_mysql_ResultObject’ has no member named ‘use’ _mysql.c:380: warning: implicit declaration of function ‘mysql_use_result’ _mysql.c:380: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c:382: warning: implicit declaration of function ‘mysql_store_result’ _mysql.c:382: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c:383: error: ‘_mysql_ResultObject’ has no member named ‘result’ _mysql.c:386: error: ‘_mysql_ResultObject’ has no member named ‘converter’ _mysql.c:389: warning: implicit declaration of function ‘mysql_num_fields’ _mysql.c:390: error: ‘_mysql_ResultObject’ has no member named ‘nfields’ _mysql.c:391: error: ‘_mysql_ResultObject’ has no member named ‘converter’ _mysql.c:392: warning: implicit declaration of function ‘mysql_fetch_fields’ _mysql.c:438: error: ‘_mysql_ResultObject’ has no member named ‘converter’ _mysql.c: In function ‘_mysql_ResultObject_traverse’: _mysql.c:450: error: ‘_mysql_ResultObject’ has no member named ‘converter’ _mysql.c:451: error: ‘_mysql_ResultObject’ has no member named ‘converter’ _mysql.c: In function ‘_mysql_ResultObject_clear’: _mysql.c:462: error: ‘_mysql_ResultObject’ has no member named ‘converter’ _mysql.c:462: error: ‘_mysql_ResultObject’ has no member named ‘converter’ _mysql.c:462: error: ‘_mysql_ResultObject’ has no member named ‘converter’ _mysql.c:462: error: ‘_mysql_ResultObject’ has no member named ‘converter’ _mysql.c:463: error: ‘_mysql_ResultObject’ has no member named ‘converter’ _mysql.c: In function ‘_mysql_ConnectionObject_Initialize’: _mysql.c:475: error: ‘MYSQL’ undeclared (first use in this function) _mysql.c:475: error: ‘conn’ undeclared (first use in this function) _mysql.c:500: error: ‘_mysql_ConnectionObject’ has no member named ‘converter’ _mysql.c:501: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c:525: error: ‘_mysql_ConnectionObject’ has no member named ‘converter’ _mysql.c:547: warning: implicit declaration of function ‘mysql_init’ _mysql.c:547: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c:550: warning: implicit declaration of function ‘mysql_options’ _mysql.c:550: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c:550: error: ‘MYSQL_OPT_CONNECT_TIMEOUT’ undeclared (first use in this function) _mysql.c:554: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c:554: error: ‘MYSQL_OPT_COMPRESS’ undeclared (first use in this function) _mysql.c:555: error: ‘CLIENT_COMPRESS’ undeclared (first use in this function) _mysql.c:558: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c:558: error: ‘MYSQL_OPT_NAMED_PIPE’ undeclared (first use in this function) _mysql.c:560: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c:560: error: ‘MYSQL_INIT_COMMAND’ undeclared (first use in this function) _mysql.c:562: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c:562: error: ‘MYSQL_READ_DEFAULT_FILE’ undeclared (first use in this function) _mysql.c:564: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c:564: error: ‘MYSQL_READ_DEFAULT_GROUP’ undeclared (first use in this function) _mysql.c:567: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c:567: error: ‘MYSQL_OPT_LOCAL_INFILE’ undeclared (first use in this function) _mysql.c:575: warning: implicit declaration of function ‘mysql_real_connect’ _mysql.c:575: error: ‘_mysql_ConnectionObject’ has no member named ‘connection’ _mysql.c:590: error: ‘_mysql_ConnectionObject’ has no member named ‘open’ _mysql.c: In function ‘_mysql_ConnectionObject_traverse’: _mysql.c:671: error: ‘_mysql_ConnectionObject’ has no member named ‘converter’ _mysql.c:

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  • Optional Parameters and Named Arguments in C# 4 (and a cool scenario w/ ASP.NET MVC 2)

    - by ScottGu
    [In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu] This is the seventeenth in a series of blog posts I’m doing on the upcoming VS 2010 and .NET 4 release. Today’s post covers two new language feature being added to C# 4.0 – optional parameters and named arguments – as well as a cool way you can take advantage of optional parameters (both in VB and C#) with ASP.NET MVC 2. Optional Parameters in C# 4.0 C# 4.0 now supports using optional parameters with methods, constructors, and indexers (note: VB has supported optional parameters for awhile). Parameters are optional when a default value is specified as part of a declaration.  For example, the method below takes two parameters – a “category” string parameter, and a “pageIndex” integer parameter.  The “pageIndex” parameter has a default value of 0, and as such is an optional parameter: When calling the above method we can explicitly pass two parameters to it: Or we can omit passing the second optional parameter – in which case the default value of 0 will be passed:   Note that VS 2010’s Intellisense indicates when a parameter is optional, as well as what its default value is when statement completion is displayed: Named Arguments and Optional Parameters in C# 4.0 C# 4.0 also now supports the concept of “named arguments”.  This allows you to explicitly name an argument you are passing to a method – instead of just identifying it by argument position.  For example, I could write the code below to explicitly identify the second argument passed to the GetProductsByCategory method by name (making its usage a little more explicit): Named arguments come in very useful when a method supports multiple optional parameters, and you want to specify which arguments you are passing.  For example, below we have a method DoSomething that takes two optional parameters: We could use named arguments to call the above method in any of the below ways: Because both parameters are optional, in cases where only one (or zero) parameters is specified then the default value for any non-specified arguments is passed. ASP.NET MVC 2 and Optional Parameters One nice usage scenario where we can now take advantage of the optional parameter support of VB and C# is with ASP.NET MVC 2’s input binding support to Action methods on Controller classes. For example, consider a scenario where we want to map URLs like “Products/Browse/Beverages” or “Products/Browse/Deserts” to a controller action method.  We could do this by writing a URL routing rule that maps the URLs to a method like so: We could then optionally use a “page” querystring value to indicate whether or not the results displayed by the Browse method should be paged – and if so which page of the results should be displayed.  For example: /Products/Browse/Beverages?page=2. With ASP.NET MVC 1 you would typically handle this scenario by adding a “page” parameter to the action method and make it a nullable int (which means it will be null if the “page” querystring value is not present).  You could then write code like below to convert the nullable int to an int – and assign it a default value if it was not present in the querystring: With ASP.NET MVC 2 you can now take advantage of the optional parameter support in VB and C# to express this behavior more concisely and clearly.  Simply declare the action method parameter as an optional parameter with a default value: C# VB If the “page” value is present in the querystring (e.g. /Products/Browse/Beverages?page=22) then it will be passed to the action method as an integer.  If the “page” value is not in the querystring (e.g. /Products/Browse/Beverages) then the default value of 0 will be passed to the action method.  This makes the code a little more concise and readable. Summary There are a bunch of great new language features coming to both C# and VB with VS 2010.  The above two features (optional parameters and named parameters) are but two of them.  I’ll blog about more in the weeks and months ahead. If you are looking for a good book that summarizes all the language features in C# (including C# 4.0), as well provides a nice summary of the core .NET class libraries, you might also want to check out the newly released C# 4.0 in a Nutshell book from O’Reilly: It does a very nice job of packing a lot of content in an easy to search and find samples format. Hope this helps, Scott

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  • C# 4.0: Covariance And Contravariance In Generics

    - by Paulo Morgado
    C# 4.0 (and .NET 4.0) introduced covariance and contravariance to generic interfaces and delegates. But what is this variance thing? According to Wikipedia, in multilinear algebra and tensor analysis, covariance and contravariance describe how the quantitative description of certain geometrical or physical entities changes when passing from one coordinate system to another.(*) But what does this have to do with C# or .NET? In type theory, a the type T is greater (>) than type S if S is a subtype (derives from) T, which means that there is a quantitative description for types in a type hierarchy. So, how does covariance and contravariance apply to C# (and .NET) generic types? In C# (and .NET), variance applies to generic type parameters and not to the resulting generic type. A generic type parameter is: covariant if the ordering of the generic types follows the ordering of the generic type parameters: Generic<T> = Generic<S> for T = S. contravariant if the ordering of the generic types is reversed from the ordering of the generic type parameters: Generic<T> = Generic<S> for T = S. invariant if neither of the above apply. If this definition is applied to arrays, we can see that arrays have always been covariant because this is valid code: object[] objectArray = new string[] { "string 1", "string 2" }; objectArray[0] = "string 3"; objectArray[1] = new object(); However, when we try to run this code, the second assignment will throw an ArrayTypeMismatchException. Although the compiler was fooled into thinking this was valid code because an object is being assigned to an element of an array of object, at run time, there is always a type check to guarantee that the runtime type of the definition of the elements of the array is greater or equal to the instance being assigned to the element. In the above example, because the runtime type of the array is array of string, the first assignment of array elements is valid because string = string and the second is invalid because string = object. This leads to the conclusion that, although arrays have always been covariant, they are not safely covariant – code that compiles is not guaranteed to run without errors. In C#, the way to define that a generic type parameter as covariant is using the out generic modifier: public interface IEnumerable<out T> { IEnumerator<T> GetEnumerator(); } public interface IEnumerator<out T> { T Current { get; } bool MoveNext(); } Notice the convenient use the pre-existing out keyword. Besides the benefit of not having to remember a new hypothetic covariant keyword, out is easier to remember because it defines that the generic type parameter can only appear in output positions — read-only properties and method return values. In a similar way, the way to define a type parameter as contravariant is using the in generic modifier: public interface IComparer<in T> { int Compare(T x, T y); } Once again, the use of the pre-existing in keyword makes it easier to remember that the generic type parameter can only be used in input positions — write-only properties and method non ref and non out parameters. Because covariance and contravariance apply only to the generic type parameters, a generic type definition can have both covariant and contravariant generic type parameters in its definition: public delegate TResult Func<in T, out TResult>(T arg); A generic type parameter that is not marked covariant (out) or contravariant (in) is invariant. All the types in the .NET Framework where variance could be applied to its generic type parameters have been modified to take advantage of this new feature. In summary, the rules for variance in C# (and .NET) are: Variance in type parameters are restricted to generic interface and generic delegate types. A generic interface or generic delegate type can have both covariant and contravariant type parameters. Variance applies only to reference types; if you specify a value type for a variant type parameter, that type parameter is invariant for the resulting constructed type. Variance does not apply to delegate combination. That is, given two delegates of types Action<Derived> and Action<Base>, you cannot combine the second delegate with the first although the result would be type safe. Variance allows the second delegate to be assigned to a variable of type Action<Derived>, but delegates can combine only if their types match exactly. If you want to learn more about variance in C# (and .NET), you can always read: Covariance and Contravariance in Generics — MSDN Library Exact rules for variance validity — Eric Lippert Events get a little overhaul in C# 4, Afterward: Effective Events — Chris Burrows Note: Because variance is a feature of .NET 4.0 and not only of C# 4.0, all this also applies to Visual Basic 10.

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  • List of Commonly Used Value Types in XNA Games

    - by Michael B. McLaughlin
    Most XNA programmers are concerned about generating garbage. More specifically about allocating GC-managed memory (GC stands for “garbage collector” and is both the name of the class that provides access to the garbage collector and an acronym for the garbage collector (as a concept) itself). Two of the major target platforms for XNA (Windows Phone 7 and Xbox 360) use variants of the .NET Compact Framework. On both variants, the GC runs under various circumstances (Windows Phone 7 and Xbox 360). Of concern to XNA programmers is the fact that it runs automatically after a fixed amount of GC-managed memory has been allocated (currently 1MB on both systems). Many beginning XNA programmers are unaware of what constitutes GC-managed memory, though. So here’s a quick overview. In .NET, there are two different “types” of types: value types and reference types. Only reference types are managed by the garbage collector. Value types are not managed by the garbage collector and are instead managed in other ways that are implementation dependent. For purposes of XNA programming, the important point is that they are not managed by the GC and thus do not, by themselves, increment that internal 1 MB allocation counter. (n.b. Structs are value types. If you have a struct that has a reference type as a member, then that reference type, when instantiated, will still be allocated in the GC-managed memory and will thus count against the 1 MB allocation counter. Putting it in a struct doesn’t change the fact that it gets allocated on the GC heap, but the struct itself is created outside of the GC’s purview). Both value types and reference types use the keyword ‘new’ to allocate a new instance of them. Sometimes this keyword is hidden by a method which creates new instances for you, e.g. XmlReader.Create. But the important thing to determine is whether or not you are dealing with a value types or a reference type. If it’s a value type, you can use the ‘new’ keyword to allocate new instances of that type without incrementing the GC allocation counter (except as above where it’s a struct with a reference type in it that is allocated by the constructor, but there are no .NET Framework or XNA Framework value types that do this so it would have to be a struct you created or that was in some third-party library you were using for that to even become an issue). The following is a list of most all of value types you are likely to use in a generic XNA game: AudioCategory (used with XACT; not available on WP7) AvatarExpression (Xbox 360 only, but exposed on Windows to ease Xbox development) bool BoundingBox BoundingSphere byte char Color DateTime decimal double any enum (System.Enum itself is a class, but all enums are value types such that there are no GC allocations for enums) float GamePadButtons GamePadCapabilities GamePadDPad GamePadState GamePadThumbSticks GamePadTriggers GestureSample int IntPtr (rarely but occasionally used in XNA) KeyboardState long Matrix MouseState nullable structs (anytime you see, e.g. int? something, that ‘?’ denotes a nullable struct, also called a nullable type) Plane Point Quaternion Ray Rectangle RenderTargetBinding sbyte (though I’ve never seen it used since most people would just use a short) short TimeSpan TouchCollection TouchLocation TouchPanelCapabilities uint ulong ushort Vector2 Vector3 Vector4 VertexBufferBinding VertexElement VertexPositionColor VertexPositionColorTexture VertexPositionNormalTexture VertexPositionTexture Viewport So there you have it. That’s not quite a complete list, mind you. For example: There are various structs in the .NET framework you might make use of. I left out everything from the Microsoft.Xna.Framework.Graphics.PackedVector namespace, since everything in there ventures into the realm of advanced XNA programming anyway (n.b. every single instantiable thing in that namespace is a struct and thus a value type; there are also two interfaces but interfaces cannot be instantiated at all and thus don’t figure in to this discussion). There are so many enums you’re likely to use (PlayerIndex, SpriteSortMode, SpriteEffects, SurfaceFormat, etc.) that including them would’ve flooded the list and reduced its utility. So I went with “any enum” and trust that you can figure out what the enums are (and it’s rare to use ‘new’ with an enum anyway). That list also doesn’t include any of the pre-defined static instances of some of the classes (e.g. BlendState.AlphaBlend, BlendState.Opaque, etc.) which are already allocated such that using them doesn’t cause any new allocations and therefore doesn’t increase that 1 MB counter. That list also has a few misleading things. VertexElement, VertexPositionColor, and all the other vertex types are structs. But you’re only likely to ever use them as an array (for use with VertexBuffer or DynamicVertexBuffer), and all arrays are reference types (even arrays of value types such as VertexPositionColor[ ] or int[ ]). * So that’s it for now. The note below may be a bit confusing (it deals with how the GC works and how arrays are managed in .NET). If so, you can probably safely ignore it for now but feel free to ask any questions regardless. * Arrays of value types (where the value type doesn’t contain any reference type members) are much faster for the GC to examine than arrays of reference types, so there is a definite benefit to using arrays of value types where it makes sense. But creating arrays of value types does cause the GC’s allocation counter to increase. Indeed, allocating a large array of a value type is one of the quickest ways to increment the allocation counter since a .NET array is a sequential block of memory. An array of reference types is just a sequential block of references (typically 4 bytes each) while an array of value types is a sequential block of instances of that type. So for an array of Vector3s it would be 12 bytes each since each float is 4 bytes and there are 3 in a Vector3; for an array of VertexPositionNormalTexture structs it would typically be 32 bytes each since it has two Vector3s and a Vector2. (Note that there are a few additional bytes taken up in the creation of an array, typically 12 but sometimes 16 or possibly even more, which depend on the implementation details of the array type on the particular platform the code is running on).

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  • Do we still have a case against the goto statement? [closed]

    - by FredOverflow
    Possible Duplicate: Is it ever worthwhile using goto? In a recent article, Andrew Koenig writes: When asked why goto statements are harmful, most programmers will say something like "because they make programs hard to understand." Press harder, and you may well hear something like "I don't really know, but that's what I was taught." For that reason, I'd like to summarize Dijkstra's arguments. He then shows two program fragments, one without a goto and and one with a goto: if (n < 0) n = 0; Assuming that n is a variable of a built-in numeric type, we know that after this code, n is nonnegative. Suppose we rewrite this fragment: if (n >= 0) goto nonneg; n = 0; nonneg: ; In theory, this rewrite should have the same effect as the original. However, rewriting has changed something important: It has opened the possibility of transferring control to nonneg from anywhere else in the program. I emphasized the part that I don't agree with. Modern languages like C++ do not allow goto to transfer control arbitrarily. Here are two examples: You cannot jump to a label that is defined in a different function. You cannot jump over a variable initialization. Now consider composing your code of tiny functions that adhere to the single responsibility principle: int clamp_to_zero(int n) { if (n >= 0) goto n_is_not_negative: n = 0; n_is_not_negative: return n; } The classic argument against the goto statement is that control could have transferred from anywhere inside your program to the label n_is_not_negative, but this simply is not (and was never) true in C++. If you try it, you will get a compiler error, because labels are scoped. The rest of the program doesn't even see the name n_is_not_negative, so it's just not possible to jump there. This is a static guarantee! Now, I'm not saying that this version is better then the one without the goto, but to make the latter as expressive as the first one, we would at least have to insert a comment, or even better yet, an assertion: int clamp_to_zero(int n) { if (n < 0) n = 0; // n is not negative at this point assert(n >= 0); return n; } Note that you basically get the assertion for free in the goto version, because the condition n >= 0 is already written in line 1, and n = 0; satisfies the condition trivially. But that's just a random observation. It seems to me that "don't use gotos!" is one of those dogmas like "don't use multiple returns!" that stem from a time where the real problem were functions of hundreds or even thousand of lines of code. So, do we still have a case against the goto statement, other than that it is not particularly useful? I haven't written a goto in at least a decade, but it's not like I was running away in terror whenever I encountered one. 1 Ideally, I would like to see a strong and valid argument against gotos that still holds when you adhere to established programming principles for clean code like the SRP. "You can jump anywhere" is not (and has never been) a valid argument in C++, and somehow I don't like teaching stuff that is not true. 1: Also, I have never been able to resurrect even a single velociraptor, no matter how many gotos I tried :(

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  • Memento with optional state?

    - by Korey Hinton
    EDIT: As pointed out by Steve Evers and pdr, I am not correctly implementing the Memento pattern, my design is actually State pattern. Menu Program I built a console-based menu program with multiple levels that selects a particular test to run. Each level more precisely describes the operation. At any level you can type back to go back one level (memento). Level 1: Server Type? [1] Server A [2] Server B Level 2: Server environment? [1] test [2] production Level 3: Test type? [1] load [2] unit Level 4: Data Collection? [1] Legal docs [2] Corporate docs Level 4.5 (optional): Load Test Type [2] Multi TIF [2] Single PDF Level 5: Command Type? [1] Move [2] Copy [3] Remove [4] Custom Level 6: Enter a keyword [setup, cleanup, run] Design States PROBLEM: Right now the STATES enum is the determining factor as to what state is BACK and what state is NEXT yet it knows nothing about what the current memento state is. Has anyone experienced a similar issue and found an effective way to handle mementos with optional state? static enum STATES { SERVER, ENVIRONMENT, TEST_TYPE, COLLECTION, COMMAND_TYPE, KEYWORD, FINISHED } Possible Solution (Not-flexible) In reference to my code below, every case statement in the Menu class could check the state of currentMemo and then set the STATE (enum) accordingly to pass to the Builder. However, this doesn't seem flexible very flexible to change and I'm struggling to see an effective way refactor the design. class Menu extends StateConscious { private State state; private Scanner reader; private ServerUtils utility; Menu() { state = new State(); reader = new Scanner(System.in); utility = new ServerUtils(); } // Recurring menu logic public void startPromptingLoop() { List<State> states = new ArrayList<>(); states.add(new State()); boolean redoInput = false; boolean userIsDone = false; while (true) { // get Memento from last loop Memento currentMemento = states.get(states.size() - 1) .saveMemento(); if (currentMemento == null) currentMemento = new Memento.Builder(0).build(); if (!redoInput) System.out.println(currentMemento.prompt); redoInput = false; // prepare Memento for next loop Memento nextMemento = null; STATES state = STATES.values()[states.size() - 1]; // get user input String selection = reader.nextLine(); switch (selection) { case "exit": reader.close(); return; // only escape case "quit": nextMemento = new Memento.Builder(first(), currentMemento, selection).build(); states.clear(); break; case "back": nextMemento = new Memento.Builder(previous(state), currentMemento, selection).build(); if (states.size() <= 1) { states.remove(0); } else { states.remove(states.size() - 1); states.remove(states.size() - 1); } break; case "1": nextMemento = new Memento.Builder(next(state), currentMemento, selection).build(); break; case "2": nextMemento = new Memento.Builder(next(state), currentMemento, selection).build(); break; case "3": nextMemento = new Memento.Builder(next(state), currentMemento, selection).build(); break; case "4": nextMemento = new Memento.Builder(next(state), currentMemento, selection).build(); break; default: if (state.equals(STATES.CATEGORY)) { String command = selection; System.out.println("Executing " + command + " command on: " + currentMemento.type + " " + currentMemento.environment); utility.executeCommand(currentMemento.nickname, command); userIsDone = true; states.clear(); nextMemento = new Memento.Builder(first(), currentMemento, selection).build(); } else if (state.equals(STATES.KEYWORD)) { nextMemento = new Memento.Builder(next(state), currentMemento, selection).build(); states.clear(); nextMemento = new Memento.Builder(first(), currentMemento, selection).build(); } else { redoInput = true; System.out.println("give it another try"); continue; } break; } if (userIsDone) { // start the recurring menu over from the beginning for (int i = 0; i < states.size(); i++) { if (i != 0) { states.remove(i); // remove all except first } } reader = new Scanner(System.in); this.state = new State(); userIsDone = false; } if (!redoInput) { this.state.restoreMemento(nextMemento); states.add(this.state); } } } }

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  • Is Visual Source Safe (The latest Version) really that bad? Why? What's the Best Alternative? Why? [closed]

    - by hanzolo
    Over the years I've constantly heard horror stories, had people say "Real Programmers Dont Use VSS", and so on. BUT, then in the workplace I've worked at two companies, one, a very well known public facing high traffic website, and another high end Financial Services "Web-Based" hosted solution catering to some very large, very well known companies, which is where I currently Reside and everything's working just fine (KNOCK KNOCK!!). I'm constantly interfacing with EXTREMELY Old technology with some of these financial institutions.. OLD LIKE YOU WOULDN'T BELIEVE.. which leads me to the conclusion that if it works "LEAVE IT", and that maybe there's some value in old technology? at least enough value to overrule a rewrite!? right?? Is there something fundamentally flawed with the underlying technology that VSS uses? I have a feeling that if i said "someone said VSS Sucks" they would beg to differ, most likely give me this look like i dont know -ish, and I'd never gain back their respect and my credibility (well, that'll be hard to blow.. lol), BUT, give me an argument that I can take to someone whose been coding for 30 years, that builds Platforms that leverage current technology (.NET 3.5 / SQL 2008 R2 ), write's their own ORM with scaffolding and is able to provide a quality platform that supports thousands of concurrent users on a multi-tenant hosted solution, and does not agree with any benefits from having Source Control Integrated, and yet uses the Infamous Visual Source Safe. I have extensive experience with TFS up to 2010, and honestly I think it's great when a team (beyond developers) can embrace it. I've worked side by side with someone whose a die hard SVN'r and from a purist standpoint, I see the beauty in it (I need a bit more, out of my SS, but it surely suffices). So, why are such smarties not running away from Visual Source Safe? surely if it was so bad, it would've have been realized by now, and I would not be sitting here with this simple old, Check In, Check Out, Version Resistant, Label Intensive system. But here I am... I would love to drop an argument that would be the end all argument, but if it's a matter of opinion and personal experience, there seems to be too much leeway for keeping VSS. UPDATE: I guess the best case is to have the VSS supporters check other people's experiences and draw from that until we (please no) experience the breaking factor ourselves. Until then, i wont be engaging in a discussion to migrate off of VSS.. UPDATE 11-2012: So i was able to convince everyone at my work place that since MS is sun downing Visual Source Safe it might be time to migrate over to TFS. I was able to convince them and have recently upgraded our team to Visual Studio 2012 and TFS 2012. The migration was fairly painless, had to run analyze.exe which found a bunch of errors (not sure they'll ever affect the project) and then manually run the VSSConverter.exe. Again, painless, except it took 16 hours to migrate 5 years worth of everything.. and now we're on TFS.. much more integrated.. much more cooler.. so all in all, VSS served it's purpose for years without hick-up. There were no horror stories and Visual Source Save as source control worked just fine. so to all the nay sayers (me included). there's nothing wrong with using VSS. i wouldnt start a new project with it, and i would definitely consider migrating to TFS. (it's really not super difficult and a new "wizard" type converter is due out any day now so migrating should be painless). But from my experience, it worked just fine and got the job done.

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  • LINQ to Entities exceptions (ElementAtOrDefault and CompareObjectEqual)

    - by OffApps Cory
    I am working on a shipping platform which will eventually automate shipping through several major carriers. I have a ShipmentsView Usercontrol which displayes a list of Shipments (returned by EntityFramework), and when a user clicks on a shipment item, it spawns a ShipmentEditView and passes the ShipmentID (RecordKey) to that view. I initially wrestled with trying to get the context from the parent (ShipmentsView) and finally gave up resolving to get to it later. I wanted to do this to keep a single instance of the context. anyhow, I now create a new instance of the context in my ShipmentEditViewModel, and query against it for the Shipment record. I know I could just pass the record, but I wanted to use the Ocean Framework that Karl Shifflett wrote and don't want to muck about writing new transition methods. So anyhow, I query and when stepping through, I can see that it returns a record, as soon as execution reached the point where it assigned the query result to the e.Result property, it throws up the following exception depending on the query I used. LINQToEntities Dim RecordID As Decimal = CDec(e.Argument) Dim myResult = From ship In _Context.Shipment _ Where ship.ShipID = e.Argument _ Select ship Select Case myResult.Count Case 0 e.Result = New Shipment Case 1 e.Result = myResult(0) Case Else e.Result = Nothing End Select "LINQ to Entities does not recognize the method 'System.Object.CompareObjectEqual(System.Object, System.Object, Boolean)' method, and this method cannot be translated into a store expression. LINQToEntities via Method calls Dim RecordID As Decimal = CDec(e.Argument) Dim myResult = _Context.Shipment.Where(Function(s) s.ShipID = RecordID) Select Case myResult.Count Case 0 e.Result = New Shipment Case 1 e.Result = myResult(0) Case Else e.Result = Nothing End Select LINQ to Entities does not recognize the method 'SnazzyShippingDAL.Shipment ElementAtOrDefault[Shipment] (System.Linq.IQueryable`1[SnazzyShippingDAL.Shipment], Int32)' method, and this method cannot be translated into a store expression. I have been trying to get this thing to display a record for like three days. i am seriously thinking about going back and re=-engineering it without the MVVM pattern (which I realize I am only starting to learn and understand) if only to make the &$^%ed thing work. Any help will be muchly appreciated. Cory

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  • Logic inside an enum

    - by Vivin Paliath
    My colleagues and I were having a discussion regarding logic in enums. My personal preference is to not have any sort of logic in Java enums (although Java provides the ability to do that). The discussion in this cased centered around having a convenience method inside the enum that returned a map: public enum PackageTypes { Letter("01", "Letter"), .. .. Tube("02", "Packaging Tube"); private String packageCode; private String packageDescription; .. .. public static Map<String, String> toMap() { Map<String, String> map = new LinkedHashMap<String, String>(); for(PackageType packageType : PackageType.values()) { map.put(packageType.getPackageCode(), packageType.getPackageDescription()); } return map; } } My personal preference is to pull this out into a service. The argument for having the method inside the enum centered around convenience. The idea was that you don't have to go to a service to get it, but can query the enum directly. My argument centered around separation of concern and abstracting any kind of logic out to a service. I didn't think "convenience" was a strong argument to put this method inside an enum. From a best-practices perspective, which one is better? Or does it simply come down to a matter of personal preference and code style?

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  • Chunked responses in libevent2

    - by Sri
    Hi I am trying to do a chunked response (of large files) in libevent this way:: evhttp_send_reply_start(request, HTTP_OK, "OK"); int fd = open("filename", O_RDONLY); size_t fileSize = <get_file_size>; struct evbuffer *databuff = NULL; for (off_t offset = 0;offset < fileSize;) { databuff = evbuffer_new(); size_t bytesLeft = fileSize - offset; size_t bytesToRead = bytesLeft > MAX_READ_SIZE ? MAX_READ_SIZE : bytesLeft; evbuffer_add_file(databuff, fd, offset, bytesToRead); offset += bytesToRead; evhttp_send_reply_chunk(request, databuff); // send it evbuffer_free(databuff); // destroy it } evhttp_send_reply_end(request); fclose(fptr); Problem is with this I have a feeling the add_file is asynchronous so the 3rd or so evhttp_send_reply_chunk gives me an error (or something similar): [warn] evhttp_send_chain Closed(45): Bad file descriptor I set MAX_READ_SIZE to be 8 to actually test out chunked transfer encoding. I noticed there was a evhttp_request_set_chunked_cb (struct evhttp_request *, void(*cb)(struct evhttp_request *, void *)) method I could use but could not find any examples on how to use. For instance, how could I pass an argument to the callback? The argument seems to be the same argument that was passed to the request handler which is not what I want, because I want to create an object that holds the file descriptor and the file offset I am sending out. Appreciate all help. Thanks in advance Sri

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  • LaTeX limitation?

    - by Jayen
    Hi, I've hit an annoying problem in LaTeX. I've got a tex file of about 1000 lines. I've already got a few figures, but when I try to add another figure, It barfs with: ! Undefined control sequence. <argument> ... \sf@size \z@ \selectfont \@currbox l.937 \begin{figure}[t] If I move the figure to other parts of the file, I can get similar errors on different lines: ! Undefined control sequence. <argument> ... \sf@size \z@ \selectfont \@currbox l.657 \paragraph {A Centering Algorithm} If I comment out the figure, all is ok. %\begin{figure}[t] % \caption{Example decision tree, from Reiter and Dale [2000]} % \label{fig:relation-decision-tree} % \centering % \includegraphics[keepaspectratio=true]{./relation-decision-tree.eps} %\end{figure} If I keep just the begin and end like: \begin{figure}%[t] % \caption{Example decision tree, from Reiter and Dale [2000]} % \label{fig:relation-decision-tree} % \centering % \includegraphics[keepaspectratio=true]{./relation-decision-tree.eps} \end{figure} I get: ! Undefined control sequence. <argument> ... \sf@size \z@ \selectfont \@currbox l.942 \end {figure} At first, I thought maybe LaTeX has hit some limit, and I tried playing with the ulimits, but that didn't help. Any ideas? i've got other figures with graphics already. my preamble looks like: \documentclass[acmcsur,acmnow]{acmtrans2n} \usepackage{array} \usepackage{lastpage} \usepackage{pict2e} \usepackage{amsmath} \usepackage{varioref} \usepackage{epsfig} \usepackage{graphics} \usepackage{qtree} \usepackage{rotating} \usepackage{tree-dvips} \usepackage{mdwlist} \makecompactlist{quote*}{quote} \usepackage{verbatim} \usepackage{ulem}

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  • 'Must Override a Superclass Method' Errors after importing a project into Eclipse

    - by Tim H
    Anytime I have to re-import my projects into Eclipse (if I reinstalled Eclipse, or changed the location of the projects), almost all of my overridden methods are not formatted correctly, causing the error 'The method ?????????? must override a superclass method'. It may be noteworthy to mention this is with Android projects - for whatever reason, the method argument values are not always populated, so I have to manually populate them myself. For instance: list.setOnCreateContextMenuListener(new OnCreateContextMenuListener() { public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) { //These arguments have their correct names } }); will be initially populated like this: list.setOnCreateContextMenuListener(new OnCreateContextMenuListener() { public void onCreateContextMenu(ContextMenu arg1, View arg2, ContextMenuInfo arg3) { //This methods arguments were not automatically provided } }); The odd thing is, if I remove my code, and have Eclipse automatically recreate the method, it uses the same argument names I already had, so I don't really know where the problem is, other then it auto-formatting the method for me. This becomes quite a pain having to manually recreate ALL my overridden methods by hand. If anyone can explain why this happens or how to fix it .. I would be very happy. Maybe it is due to the way I am formatting the methods, which are inside an argument of another method?

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  • Looking for examples of "real" uses of continuations

    - by Sébastien RoccaSerra
    I'm trying to grasp the concept of continuations and I found several small teaching examples like this one from the Wikipedia article: (define the-continuation #f) (define (test) (let ((i 0)) ; call/cc calls its first function argument, passing ; a continuation variable representing this point in ; the program as the argument to that function. ; ; In this case, the function argument assigns that ; continuation to the variable the-continuation. ; (call/cc (lambda (k) (set! the-continuation k))) ; ; The next time the-continuation is called, we start here. (set! i (+ i 1)) i)) I understand what this little function does, but I can't see any obvious application of it. While I don't expect to use continuations all over my code anytime soon, I wish I knew a few cases where they can be appropriate. So I'm looking for more explicitely usefull code samples of what continuations can offer me as a programmer. Cheers!

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