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  • Procedural object generation and unique identification

    - by 2080
    My question relates to procedural content generation and data management of the emerging objects in a database. I assume a networked game, with a server-client model. Unspecified objects in the game world are generated while the game is running with procedural algorithms (for example perlin noise). The players (/clients) can modify the properties of these objects, but have to notify the server of these changes. How could this communication address unique objects, so that both the server and the client know of which object they are speaking? Not only the inner properties of the objects can differ, but also visible, such as the position. When the player wants to select one of these objects the game has to find out the id - does anyone know which methods or algorithms can accomplish that?

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  • Identifying which pattern fits better.

    - by Daniel Grillo
    I'm developing a software to program a device. I have some commands like Reset, Read_Version, Read_memory, Write_memory, Erase_memory. Reset and Read_Version are fixed. They don't need parameters. Read_memory and Erase_memory need the same parameters that are Length and Address. Write_memory needs Lenght, Address and Data. For each command, I have the same steps in sequence, that are something like this sendCommand, waitForResponse, treatResponse. I'm having difficulty to identify which pattern should I use. Factory, Template Method, Strategy or other pattern. Edit I'll try to explain better taking in count the given comments and answers. I've already done this software and now I'm trying to refactoring it. I'm trying to use patterns, even if it is not necessary because I'm taking advantage of this little software to learn about some patterns. Despite I think that one (or more) pattern fits here and it could improve my code. When I want to read version of the software of my device, I don't have to assembly the command with parameters. It is fixed. So I have to send it. After wait for response. If there is a response, treat (or parse) it and returns. To read a portion of the memory (maximum of 256 bytes), I have to assembly the command using the parameters Len and Address. So I have to send it. After wait for response. If there is a response, treat (or parse) it and returns. To write a portion in the memory (maximum of 256 bytes), I have to assembly the command using the parameters Len, Address and Data. So I have to send it. After wait for response. If there is a response, treat (or parse) it and returns. I think that I could use Template Method because I have almost the same algorithm for all. But the problem is some commands are fixes, others have 2 or 3 parameters. I think that parameters should be passed on the constructor of the class. But each class will have a constructor overriding the abstract class constructor. Is this a problem for the template method? Should I use other pattern?

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  • Is premature optimization really the root of all evil?

    - by Craig Day
    A colleague of mine today committed a class called ThreadLocalFormat, which basically moved instances of Java Format classes into a thread local, since they are not thread safe and "relatively expensive" to create. I wrote a quick test and calculated that I could create 200,000 instances a second, asked him was he creating that many, to which he answered "nowhere near that many". He's a great programmer and everyone on the team is highly skilled so we have no problem understanding the resulting code, but it was clearly a case of optimizing where there is no real need. He backed the code out at my request. What do you think? Is this a case of "premature optimization" and how bad is it really?

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  • Searching for entity awareness in 3D space algorithm and data structure

    - by Khanser
    I'm trying to do some huge AI system just for the fun and I've come to this problem. How can I let the AI entities know about each other without getting the CPU to perform redundant and costly work? Every entity has a spatial awareness zone and it has to know what's inside when it has to decide what to do. First thoughts, for every entity test if the other entities are inside the first's reach. Ok, so it was the first try and yep, that is redundant and costly. We are working with real time AI over 10000+ entities so this is not a solution. Second try, calculate some grid over the awareness zone of every entity and test whether in this zones are entities (we are working with 3D entities with float x,y,z location coordinates) testing every point in the grid with the indexed-by-coordinate entities. Well, I don't like this because is also costly, but not as the first one. Third, create some multi linked lists over the x's and y's indexed positions of the entities so when we search for an interval between x,y and z,w positions (this interval defines the square over the spatial awareness zone) over the multi linked list, we won't have 'voids'. This has the problem of finding the nearest proximity value if there isn't one at the position where we start the search. I'm not convinced with any of the ideas so I'm searching for some enlightening. Do you people have any better ideas?

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  • Using "prevent execution of method" flags

    - by tpaksu
    First of all I want to point out my concern with some pseudocode (I think you'll understand better) Assume you have a global debug flag, or class variable named "debug", class a : var debug = FALSE and you use it to enable debug methods. There are two types of usage it as I know: first in a method : method a : if debug then call method b; method b : second in the method itself: method a : call method b; method b : if not debug exit And I want to know, is there any File IO or stack pointer wise difference between these two approaches. Which usage is better, safer and why?

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  • How should I write new code when the old codebase and the environment uses lots of globals in PHP

    - by Nicola Peluchetti
    I'm working in the Wordpress environment which itself heavily relies on globals and the codebase I'm maintaining introduces some more. I want this to change and so I'm trying to think how should I handle this. For the globals our code has introduced I think I will set them as dependencies in the constructor or in getter / setter so that I don't rely on them being globals and then refactor the old codebase little by little so that we have no globals. With Wordpress globals I was thinking to wrap all WP globals inside a Wrapper class and hide them in there. Like this class WpGlobals { public static function getDb() { global $wpdb; return $wpdb; } } Would this be of any help? The idea is that I centralize all globals in one class and do not scatter them through the code, so that if Wordpress kills one of them I need to modify code only in one place. What would you do?

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  • Javascript: Avoid this and new - further reading? [closed]

    - by Thomas Deutsch
    I do not want this to end in a sort of religious discussion, i want to collect some sources for further reading on this topic. As shown here: Node.js Style and Structure Point 1: Avoid this and new you can find a good example when it could be better to use closures instead of a prototype, and to make every argument explicit. Ok, i agree - could be nice, but i need to know more. Can anyone recommend a good link? Would this make my code 100% object-pattern-free ? (no factory-, repository-, module- pattern?)

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  • Should developers make their games easier with new versions?

    - by Gil Kalai
    It seems that the game Angry Birds is becoming gradually easier with new versions. Maybe so people get the illusion of progress and satisfaction of breaking new records? I would like to know if gradual small modifications of games to enhance the sense of improvement and learning by users is known/common/standard practice in game developing. (I don't mean to say that there is anything wrong with such a practice.)

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  • Ubiquitous Language and Custom types

    - by EdvRusj
    Note that my question is referring to those attributes that even on their own already represent a concept ( ie on their own provide a cohesive meaning ). Thus such attribute needs no additional functional support and as such is self-contained. I'm also well-aware that even with self-contained attributes the custom types may prove beneficial ( for example, they give the ability to add new behavior later, when business requirements change ). Thus, my question focuses only on whether custom types for self-contained attributes really enrich Ubiquitous Language UL a) I've read that in most cases, even simple, self-contained attributes should have custom, more descriptive types rather than basic value types ( double, string ... ), because among other things, descriptive types add to the UL, while the use of basic types instead weakens the language. I understand the importance of UL, but how does having a basic type for a self-contained attribute weaken the language, since with self-contained attributes the name of the attribute already adequately describes the concept and thus contributes to the UL vocabulary? For example, the term person_age already adequately explains the concept of quantifying the number of years a person has: class Person { string person_age; } so what could we possibly gain by also introducing the term ThingAge to the UL: class person { ThingAge person_age; } thanks

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  • Why is facebook cache buggy?

    - by IAdapter
    I just started using facebook and I see that many times when I add something to my profile and visit it later its not there. I bet the reason is that the page is cached and not updated very often. Is this on purpose or is it a bug? P.S. For example I added the music I like and later I see that I did not add it, but next day when I visit again its there. I saw it in two web-browsers, so its a facebook bug. Does it has something to do with scalability?

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  • Why don't languages include implication as a logical operator?

    - by Maciej Piechotka
    It might be a strange question, but why there is no implication as a logical operator in many languages (Java, C, C++, Python Haskell - although as last one have user defined operators its trivial to add it)? I find logical implication much clearer to write (particularly in asserts or assert-like expressions) then negation with or: encrypt(buf, key, mode, iv = null) { assert (mode != ECB --> iv != null); assert (mode == ECB || iv != null); assert (implies(mode != ECB, iv != null)); // User-defined function }

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  • What is a proper way of building Winform apps with multiple "screens"

    - by CurtisHx
    What's a proper way of building a Winform app that has multiple 'screens'? For example, I'm trying to write a small backup program (mainly for giggles), and I've been dumping controls and containers onto the form. I'm using panels and group boxes to separate out the different screens (eg: I'm using a panel to hold all of the controls for the "Settings" window, and another panel to show all the current backups that have been set up). Well, my form.cs file ballooned into a massive amount of code, and I feel like I'm doing something wrong. I can hardly find anything in the file, and I'm ready to start over. This project was just for me to expand my knowledge of C# and .NET, so starting a new project is not a huge deal.

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  • Random/Procedural vs. Previously Made Level Generation

    - by PythonInProgress
    I am making a game (called "Glory") that is a top-down explorer game, and am wondering what the advantages/disadvantages of using random/procedural generation vs. pre-made levels are. There seems to be few that i can think of, other than the fact that items may be a problem to distribute in randomly generated terrain, and that the generated terrain may look weird. The downside to previously made levels is that I would need to make a level editor, though. I cannot decide what is better to use.

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  • How to implement "bullet time" in a multiplayer game?

    - by Tom
    I have never seen such a feature before, but it should provide an interesting gameplay opportunity. So yes, in a multiplayer/real-time environment (imagine FPS), how could I implement a slow motion/bullet time effect? Something like an illusion for the player that's currently slo-mo'ed. So everybody sees him "real-time", but he sees everything slowed down. Update A sidenote: keep in mind that a FPS game has to be balanced in order for it to be fun. So yes, this bullet time feature has to be solid, giving a small advantage to the "player", while not taking away from other players. Plus, there is a possibility that two players could activate their bullet time at the same time. Furthermore: I'm going to implement this in the future no matter what it takes. And, the idea is to build a whole new game engine for all this. If that gives new options, I'm more then interested in hearing the ideas. Meanwhile, here with my team we're thinking about this too, when our theory will be crafted, I'm going to share it here. Is this even possible? So, the question on "is this even possible" has been answered, now it's time to find the best solution. I'm keeping the "answer" until something exceptionally good comes up, like a prototype theory with something close to working pseudo code.

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  • Handling deleted users - separate or same table?

    - by Alan Beats
    The scenario is that I've got an expanding set of users, and as time goes by, users will cancel their accounts which we currently mark as 'deleted' (with a flag) in the same table. If users with the same email address (that's how users log in) wish to create a new account, they can signup again, but a NEW account is created. (We have unique ids for every account, so email addresses can be duplicated amongst live and deleted ones). What I've noticed is that all across our system, in the normal course of things we constantly query the users table checking the user is not deleted, whereas what I'm thinking is that we dont need to do that at all...! [Clarification1: by 'constantly querying', I meant that we have queries which are like: '... FROM users WHERE isdeleted="0" AND ...'. For example, we may need to fetch all users registered for all meetings on a particular date, so in THAT query, we also have FROM users WHERE isdeleted="0" - does this make my point clearer?] (1) continue keeping deleted users in the 'main' users table (2) keep deleted users in a separate table (mostly required for historical book-keeping) What are the pros and cons of either approach?

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  • C#.NET: How to update multiple .NET pages when a particular event occurs in one .Net page? In another words how to use Observer pattern(Publish and subscribe to events)

    Problem: Suppose you have a scenario in which you have to update multiple pages when an event occurs in main page. For example imagine you have a main page where you are dispalying a tab control. This tab control has 3 tab pages where you are loading 3 different user controls. On click of an update button in main page imagine if you have do something in all the 3 tab panels. In other words an event in main page has to be handled in many other pages. An event in main page which contains the tab control has to be handled in all the tab panels(user controls) Answer: Use Observer pattern Define a base page for the page that contains the tab control. Main page which contains the tab: Baseline_Baseline Basepage for the above main page: BaselineBasePage User control that has to be udpated for an event in main page: Baseline_PriorNonDeloitte Source Code: public class BaselineBasePage : System.Web.UI.Page { IList lstControls = new List(); public void Add(IObserver userControl) { lstControls.Add(userControl); } public void Remove(IObserver userControl) { lstControls.Remove(userControl); } public void RemoveAllUserControls() { lstControls.Clear(); } public void Update(SaveEventArgs e) { foreach (IObserver LobjControl in lstControls) { LobjControl.Save(e); } } } public interface IObserver { void Update(SaveEventArgs e); } public partial class Baseline_Baseline : BaselineBasePage { . . . this.Add(_ucPI); this.Add(_ucPI1); protected void abActionBar_saveClicked(object sender, EventArgs e) { SaveEventArgs se = new SaveEventArgs(); se.TabType = (BaselineTabType)tcBaseline.ActiveTabIndex; this.Update(se); } } Public class Baseline_PriorNonDeloitte : System.Web.UI.UserControl,IObserver { public void Update(SaveEventArgs e) { } } More info at: http://www.dofactory.com/Patterns/PatternObserver.aspx span.fullpost {display:none;}

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  • Visually and audibly unambiguous subset of the Latin alphabet?

    - by elliot42
    Imagine you give someone a card with the code "5SBDO0" on it. In some fonts, the letter "S" is difficult to visually distinguish from the number five, (as with number zero and letter "O"). Reading the code out loud, it might be difficult to distinguish "B" from "D", necessitating saying "B as in boy," "D as in dog," or using a "phonetic alphabet" instead. What's the biggest subset of letters and numbers that will, in most cases, both look unambiguous visually and sound unambiguous when read aloud? Background: We want to generate a short string that can encode as many values as possible while still being easy to communicate. Imagine you have a 6-character string, "123456". In base 10 this can encode 10^6 values. In hex "1B23DF" you can encode 16^6 values in the same number of characters, but this can sound ambiguous when read aloud. ("B" vs. "D") Likewise for any string of N characters, you get (size of alphabet)^N values. The string is limited to a length of about six characters, due to wanting to fit easily within the capacity of human working memory capacity. Thus to find the max number of values we can encode, we need to find that largest unambiguous set of letters/numbers. There's no reason we can't consider the letters G-Z, and some common punctuation, but I don't want to have to go manually pairwise compare "does G sound like A?", "does G sound like B?", "does G sound like C" myself. As we know this would be O(n^2) linguistic work to do =)...

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  • Creating new games on Android and/or iPhone

    - by James Clifton
    I have a succesfull facebook poker game that is running very nicely, now some people have asked if I can port this to other platforms - mainly mobile devices (and I have been asked to make a tablet version, do I really need a seperate version?) I am currently a PHP programmer (and game designer) and I simply dont' have the time to learn Android and other languages - so I have decided to pay third parties to program them (if viable). The information I need to know is what programming language is needed for the following four devices - Android mobile phone, iPhone, iPad and tablets? Can they all run off a central sql database? If they can't then i'm not interested :( Do any of these run FLASH? Have I covered all my main bases here? For example if a person programs for a ANDROID mobile phone is that to much differant to an ANDROID tablet? They will have slightly differant graphics (because the tablet has a greater screen area might as well use it) but do they need to be started from scratch? Same goes for iPhone/iPad, do they really need to be programmed differantly if the only differance is the graphics?

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  • Breaking up classes and methods into smaller units

    - by micahhoover
    During code reviews a couple devs have recommended I break up my methods into smaller methods. Their justification was (1) increased readability and (2) the back trace that comes back from production showing the method name is more specific to the line of code that failed. There may have also been some colorful words about functional programming. Additionally I think I may have failed an interview a while back because I didn't give an acceptable answer about when to break things up. My inclination is that when I see a bunch of methods in a class or across a bunch of files, it isn't clear to me how they flow together, and how many times each one gets called. I don't really have a good feel for the linearity of it as quickly just by eye-balling it. The other thing is a lot of people seem to place a premium of organization over content (e.g. 'Look at how organized my sock drawer is!' Me: 'Overall, I think I can get to my socks faster if you count the time it took to organize them'). Our business requirements are not very stable. I'm afraid that if the classes/methods are very granular it will take longer to refactor to requirement changes. I'm not sure how much of a factor this should be. Anyway, computer science is part art / part science, but I'm not sure how much this applies to this issue.

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  • What are good ways to find collaborators for a coding weekend?

    - by tarrasch
    Not sure if this belongs here, feel free to push it somewhere else if needed. When i was at university we would sometimes come together into a room full of beer and fast food and crank out software in a weekend. Unfortunately the group has kind of split up and its just not possible any more. My question is now: Where can i find like-minded people on the Internet that would like to do something like this? I have an idea what i wanted to do next, but of course other people have ideas too.

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  • Pro/con of using Angular directives for complex form validation/ GUI manipulation

    - by tengen
    I am building a new SPA front end to replace an existing enterprise's legacy hodgepodge of systems that are outdated and in need of updating. I am new to angular, and wanted to see if the community could give me some perspective. I'll state my problem, and then ask my question. I have to generate several series of check boxes based on data from a .js include, with data like this: $scope.fieldMappings.investmentObjectiveMap = [ {'id':"CAPITAL PRESERVATION", 'name':"Capital Preservation"}, {'id':"STABLE", 'name':"Moderate"}, {'id':"BALANCED", 'name':"Moderate Growth"}, // etc {'id':"NONE", 'name':"None"} ]; The checkboxes are created using an ng-repeat, like this: <div ng-repeat="investmentObjective in fieldMappings.investmentObjectiveMap"> ... </div> However, I needed the values represented by the checkboxes to map to a different model (not just 2-way-bound to the fieldmappings object). To accomplish this, I created a directive, which accepts a destination array destarray which is eventually mapped to the model. I also know I need to handle some very specific gui controls, such as unchecking "None" if anything else gets checked, or checking "None" if everything else gets unchecked. Also, "None" won't be an option in every group of checkboxes, so the directive needs to be generic enough to accept a validation function that can fiddle with the checked state of the checkbox group's inputs based on what's already clicked, but smart enough not to break if there is no option called "NONE". I started to do that by adding an ng-click which invoked a function in the controller, but in looking around Stack Overflow, I read people saying that its bad to put DOM manipulation code inside your controller - it should go in directives. So do I need another directive? So far: (html): <input my-checkbox-group type="checkbox" fieldobj="investmentObjective" ng-click="validationfunc()" validationfunc="clearOnNone()" destarray="investor.investmentObjective" /> Directive code: .directive("myCheckboxGroup", function () { return { restrict: "A", scope: { destarray: "=", // the source of all the checkbox values fieldobj: "=", // the array the values came from validationfunc: "&" // the function to be called for validation (optional) }, link: function (scope, elem, attrs) { if (scope.destarray.indexOf(scope.fieldobj.id) !== -1) { elem[0].checked = true; } elem.bind('click', function () { var index = scope.destarray.indexOf(scope.fieldobj.id); if (elem[0].checked) { if (index === -1) { scope.destarray.push(scope.fieldobj.id); } } else { if (index !== -1) { scope.destarray.splice(index, 1); } } }); } }; }) .js controller snippet: .controller( 'SuitabilityCtrl', ['$scope', function ( $scope ) { $scope.clearOnNone = function() { // naughty jQuery DOM manipulation code that // looks at checkboxes and checks/unchecks as needed }; The above code is done and works fine, except the naughty jquery code in clearOnNone(), which is why I wrote this question. And here is my question: after ALL this, I think to myself - I could be done already if I just manually handled all this GUI logic and validation junk with jQuery written in my controller. At what point does it become foolish to write these complicated directives that future developers will have to puzzle over more than if I had just written jQuery code that 99% of us would understand with a glance? How do other developers draw the line? I see this all over Stack Overflow. For example, this question seems like it could be answered with a dozen lines of straightforward jQuery, yet he has opted to do it the angular way, with a directive and a partial... it seems like a lot of work for a simple problem. Specifically, I suppose I would like to know: how SHOULD I be writing the code that checks whether "None" has been selected (if it exists as an option in this group of checkboxes), and then check/uncheck the other boxes accordingly? A more complex directive? I can't believe I'm the only developer that is having to implement code that is more complex than needed just to satisfy an opinionated framework.

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  • Implementing new required feature after software release

    - by TiagoBrenck
    Fake Scenario There is a software that was released 1 year ago. The software is to map and register all kind of animals on our planet. When the software was released, the client only needed to know the scientific name of the animal, a flag if it is in risk of extinction and a scale of dangerous(that is a fake software and specification, I don't want to discuss this here). There are already 100.000 animals records saved on DB. New Feature One year later, the client wants a new feature. It is really important to him to know the animals classes, and this is a required field. So he asks me to put a field to input the animal class, and this field is required. Or maybe where this animal was discovered. Problem I have already 100.000 recorded animals without a class or where it was discovered, but I need to insert a new column to storage this information and this column can't be null. I don't have a default value for this situation (there isn't a default animal class or where it was discovered). I don't want to keep the requirement rule only on my software, my DB must have this requirement too(I like to keep business rules on DB too). What are the alternatives to solve this situation? I am on a situation that this new feature cannot be previewed or reviewed for the existing records. The time already passed and I can't go back on time to get it

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  • Rails: The Law of Demeter [duplicate]

    - by user2158382
    This question already has an answer here: Rails: Law of Demeter Confusion 4 answers I am reading a book called Rails AntiPatterns and they talk about using delegation to to avoid breaking the Law of Demeter. Here is their prime example: They believe that calling something like this in the controller is bad (and I agree) @street = @invoice.customer.address.street Their proposed solution is to do the following: class Customer has_one :address belongs_to :invoice def street address.street end end class Invoice has_one :customer def customer_street customer.street end end @street = @invoice.customer_street They are stating that since you only use one dot, you are not breaking the Law of Demeter here. I think this is incorrect, because you are still going through customer to go through address to get the invoice's street. I primarily got this idea from a blog post I read: http://www.dan-manges.com/blog/37 In the blog post the prime example is class Wallet attr_accessor :cash end class Customer has_one :wallet # attribute delegation def cash @wallet.cash end end class Paperboy def collect_money(customer, due_amount) if customer.cash < due_ammount raise InsufficientFundsError else customer.cash -= due_amount @collected_amount += due_amount end end end The blog post states that although there is only one dot customer.cash instead of customer.wallet.cash, this code still violates the Law of Demeter. Now in the Paperboy collect_money method, we don't have two dots, we just have one in "customer.cash". Has this delegation solved our problem? Not at all. If we look at the behavior, a paperboy is still reaching directly into a customer's wallet to get cash out. EDIT I completely understand and agree that this is still a violation and I need to create a method in Wallet called withdraw that handles the payment for me and that I should call that method inside the Customer class. What I don't get is that according to this process, my first example still violates the Law of Demeter because Invoice is still reaching directly into Customer to get the street. Can somebody help me clear the confusion. I have been searching for the past 2 days trying to let this topic sink in, but it is still confusing.

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  • Consistency vs. Usability?

    - by dsimcha
    When designing an API, consistency often aids usability. However, sometimes they conflict where an extra API feature can be added to streamline a common case. It seems like there's somewhat of a divide over what to do here. Some designs (the Java standard library come to mind) favor consistency even if it makes common cases more verbose. Others (the Python standard library comes to mind) favor usability even if it means treating the common case as "special" to make it easier. What is your opinion on how consistency and usability should be balanced?

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  • What is the general definition of something that can be included or excluded?

    - by gutch
    When an application presents a user with a list of items, it's pretty common that it permits the user to filter the items. Often a 'filter' feature is implemented as a set of include or exclude rules. For example: include all emails from [email protected], and exclude those emails without attachments I've seen this include/exclude pattern often; for example Maven and Google Analytics filter things this way. But now that I'm implementing something like this myself, I don't know what to call something that could be either included or excluded. In specific terms: If I have a database table of filter rules, each of which either includes or excludes matching items, what is an appropriate name of the field that stores include or exclude? When displaying a list of filters to a user, what is a good way to label the include or exclude value? (as a bonus, can anyone recommend a good implementation of this kind of filtering for inspiration?)

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