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  • How to map keys in vim differently for different kinds of buffers

    - by Yogesh Arora
    The problem i am facing is that i have mapped some keys and mouse events for seraching in vim while editing a file. But those mappings impact the functionality if the quickfix buffer. I was wondering if it is possible to map keys depending on the buffer in which they are used. EDIT - I am adding more info for this question Let us consider a scenario. I want to map <C-F4> to close a buffer/window. Now this behavior could depend on a number of things. If i am editing a buffer it should just close that buffer without changing the layout of the windows. I am using buffkil plugin for this. It does not depend on extension of file but on the type of buffer. I saw in vim documentation that there are unlisted and listed buffer. So if it is listed buffer it should close using bufkill commands. If it is not a listed buffer it should use <c-w>c command to close buffer and changing the window layout. I am new at writing vim functions/scripts, can someone help me getting started on this

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  • List of values as keys for a Map

    - by thr
    I have lists of variable length where each item can be one of four unique, that I need to use as keys for another object in a map. Assume that each value can be either 0, 1, 2 or 3 (it's not integer in my real code, but a lot easier to explain this way) so a few examples of key lists could be: [1, 0, 2, 3] [3, 2, 1] [1, 0, 0, 1, 1, 3] [2, 3, 1, 1, 2] [1, 2] So, to re-iterate: each item in the list can be either 0, 1, 2 or 3 and there can be any number of items in a list. My first approach was to try to hash the contents of the array, using the built in GetHashCode() in .NET to combine the hash of each element. But since this would return an int I would have to deal with collisions manually (two equal int values are identical to a Dictionary). So my second approach was to use a quad tree, breaking down each item in the list into a Node that has four pointers (one for each possible value) to the next four possible values (with the root node representing [], an empty list), inserting [1, 0, 2] => Foo, [1, 3] => Bar and [1, 0] => Baz into this tree would look like this: Grey nodes nodes being unused pointers/nodes. Though I worry about the performance of this setup, but there will be no need to deal with hash collisions and the tree won't become to deep (there will mostly be lists with 2-6 items stored, rarely over 6). Is there some other magic way to store items with lists of values as keys that I have missed?

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  • JavaScript Class Patterns

    - by Liam McLennan
    To write object-oriented programs we need objects, and likely lots of them. JavaScript makes it easy to create objects: var liam = { name: "Liam", age: Number.MAX_VALUE }; But JavaScript does not provide an easy way to create similar objects. Most object-oriented languages include the idea of a class, which is a template for creating objects of the same type. From one class many similar objects can be instantiated. Many patterns have been proposed to address the absence of a class concept in JavaScript. This post will compare and contrast the most significant of them. Simple Constructor Functions Classes may be missing but JavaScript does support special constructor functions. By prefixing a call to a constructor function with the ‘new’ keyword we can tell the JavaScript runtime that we want the function to behave like a constructor and instantiate a new object containing the members defined by that function. Within a constructor function the ‘this’ keyword references the new object being created -  so a basic constructor function might be: function Person(name, age) { this.name = name; this.age = age; this.toString = function() { return this.name + " is " + age + " years old."; }; } var john = new Person("John Galt", 50); console.log(john.toString()); Note that by convention the name of a constructor function is always written in Pascal Case (the first letter of each word is capital). This is to distinguish between constructor functions and other functions. It is important that constructor functions be called with the ‘new’ keyword and that not constructor functions are not. There are two problems with the pattern constructor function pattern shown above: It makes inheritance difficult The toString() function is redefined for each new object created by the Person constructor. This is sub-optimal because the function should be shared between all of the instances of the Person type. Constructor Functions with a Prototype JavaScript functions have a special property called prototype. When an object is created by calling a JavaScript constructor all of the properties of the constructor’s prototype become available to the new object. In this way many Person objects can be created that can access the same prototype. An improved version of the above example can be written: function Person(name, age) { this.name = name; this.age = age; } Person.prototype = { toString: function() { return this.name + " is " + this.age + " years old."; } }; var john = new Person("John Galt", 50); console.log(john.toString()); In this version a single instance of the toString() function will now be shared between all Person objects. Private Members The short version is: there aren’t any. If a variable is defined, with the var keyword, within the constructor function then its scope is that function. Other functions defined within the constructor function will be able to access the private variable, but anything defined outside the constructor (such as functions on the prototype property) won’t have access to the private variable. Any variables defined on the constructor are automatically public. Some people solve this problem by prefixing properties with an underscore and then not calling those properties by convention. function Person(name, age) { this.name = name; this.age = age; } Person.prototype = { _getName: function() { return this.name; }, toString: function() { return this._getName() + " is " + this.age + " years old."; } }; var john = new Person("John Galt", 50); console.log(john.toString()); Note that the _getName() function is only private by convention – it is in fact a public function. Functional Object Construction Because of the weirdness involved in using constructor functions some JavaScript developers prefer to eschew them completely. They theorize that it is better to work with JavaScript’s functional nature than to try and force it to behave like a traditional class-oriented language. When using the functional approach objects are created by returning them from a factory function. An excellent side effect of this pattern is that variables defined with the factory function are accessible to the new object (due to closure) but are inaccessible from anywhere else. The Person example implemented using the functional object construction pattern is: var personFactory = function(name, age) { var privateVar = 7; return { toString: function() { return name + " is " + age * privateVar / privateVar + " years old."; } }; }; var john2 = personFactory("John Lennon", 40); console.log(john2.toString()); Note that the ‘new’ keyword is not used for this pattern, and that the toString() function has access to the name, age and privateVar variables because of closure. This pattern can be extended to provide inheritance and, unlike the constructor function pattern, it supports private variables. However, when working with JavaScript code bases you will find that the constructor function is more common – probably because it is a better approximation of mainstream class oriented languages like C# and Java. Inheritance Both of the above patterns can support inheritance but for now, favour composition over inheritance. Summary When JavaScript code exceeds simple browser automation object orientation can provide a powerful paradigm for controlling complexity. Both of the patterns presented in this article work – the choice is a matter of style. Only one question still remains; who is John Galt?

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  • JavaScript Class Patterns

    - by Liam McLennan
    To write object-oriented programs we need objects, and likely lots of them. JavaScript makes it easy to create objects: var liam = { name: "Liam", age: Number.MAX_VALUE }; But JavaScript does not provide an easy way to create similar objects. Most object-oriented languages include the idea of a class, which is a template for creating objects of the same type. From one class many similar objects can be instantiated. Many patterns have been proposed to address the absence of a class concept in JavaScript. This post will compare and contrast the most significant of them. Simple Constructor Functions Classes may be missing but JavaScript does support special constructor functions. By prefixing a call to a constructor function with the ‘new’ keyword we can tell the JavaScript runtime that we want the function to behave like a constructor and instantiate a new object containing the members defined by that function. Within a constructor function the ‘this’ keyword references the new object being created -  so a basic constructor function might be: function Person(name, age) { this.name = name; this.age = age; this.toString = function() { return this.name + " is " + age + " years old."; }; } var john = new Person("John Galt", 50); console.log(john.toString()); Note that by convention the name of a constructor function is always written in Pascal Case (the first letter of each word is capital). This is to distinguish between constructor functions and other functions. It is important that constructor functions be called with the ‘new’ keyword and that not constructor functions are not. There are two problems with the pattern constructor function pattern shown above: It makes inheritance difficult The toString() function is redefined for each new object created by the Person constructor. This is sub-optimal because the function should be shared between all of the instances of the Person type. Constructor Functions with a Prototype JavaScript functions have a special property called prototype. When an object is created by calling a JavaScript constructor all of the properties of the constructor’s prototype become available to the new object. In this way many Person objects can be created that can access the same prototype. An improved version of the above example can be written: function Person(name, age) { this.name = name; this.age = age; } Person.prototype = { toString: function() { return this.name + " is " + this.age + " years old."; } }; var john = new Person("John Galt", 50); console.log(john.toString()); In this version a single instance of the toString() function will now be shared between all Person objects. Private Members The short version is: there aren’t any. If a variable is defined, with the var keyword, within the constructor function then its scope is that function. Other functions defined within the constructor function will be able to access the private variable, but anything defined outside the constructor (such as functions on the prototype property) won’t have access to the private variable. Any variables defined on the constructor are automatically public. Some people solve this problem by prefixing properties with an underscore and then not calling those properties by convention. function Person(name, age) { this.name = name; this.age = age; } Person.prototype = { _getName: function() { return this.name; }, toString: function() { return this._getName() + " is " + this.age + " years old."; } }; var john = new Person("John Galt", 50); console.log(john.toString()); Note that the _getName() function is only private by convention – it is in fact a public function. Functional Object Construction Because of the weirdness involved in using constructor functions some JavaScript developers prefer to eschew them completely. They theorize that it is better to work with JavaScript’s functional nature than to try and force it to behave like a traditional class-oriented language. When using the functional approach objects are created by returning them from a factory function. An excellent side effect of this pattern is that variables defined with the factory function are accessible to the new object (due to closure) but are inaccessible from anywhere else. The Person example implemented using the functional object construction pattern is: var john = new Person("John Galt", 50); console.log(john.toString()); var personFactory = function(name, age) { var privateVar = 7; return { toString: function() { return name + " is " + age * privateVar / privateVar + " years old."; } }; }; var john2 = personFactory("John Lennon", 40); console.log(john2.toString()); Note that the ‘new’ keyword is not used for this pattern, and that the toString() function has access to the name, age and privateVar variables because of closure. This pattern can be extended to provide inheritance and, unlike the constructor function pattern, it supports private variables. However, when working with JavaScript code bases you will find that the constructor function is more common – probably because it is a better approximation of mainstream class oriented languages like C# and Java. Inheritance Both of the above patterns can support inheritance but for now, favour composition over inheritance. Summary When JavaScript code exceeds simple browser automation object orientation can provide a powerful paradigm for controlling complexity. Both of the patterns presented in this article work – the choice is a matter of style. Only one question still remains; who is John Galt?

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  • Foreign key not working in MySQL: Why can I INSERT a value that's not in the foreign column?

    - by stalepretzel
    I've created a table in MySQL: CREATE TABLE actions ( A_id int NOT NULL AUTO_INCREMENT, type ENUM('rate','report','submit','edit','delete') NOT NULL, Q_id int NOT NULL, U_id int NOT NULL, date DATE NOT NULL, time TIME NOT NULL, rate tinyint(1), PRIMARY KEY (A_id), CONSTRAINT fk_Question FOREIGN KEY (Q_id) REFERENCES questions(P_id), CONSTRAINT fk_User FOREIGN KEY (U_id) REFERENCES users(P_id)); This created the table I wanted just fine (although a "DESCRIBE actions;" command showed me that the foreign keys were keys of type MUL, and I'm not sure what this means). However, when I try to enter a Q_id or a U_id that does not exist in the questions or users tables, MySQL still allows these values. What did I do wrong? How can I prevent a table with a foreign key from accepting invalid data? If I add TYPE=InnoDB to the end, I get an error: ERROR 1005 (HY000): Can't create table './quotes/actions.frm' (errno: 150) Why might that happen? I'm told that it's important to enforce data integrity with functional foreign keys, but also that InnoDB should not be used with MySQL. What do you recommend?

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  • Can I use foreign key restrictions to return meaningful UI errors with PHP

    - by Shane
    I want to start by saying that I am a big fan of using foreign keys and have a tendency to use them even on small projects to keep my database from being filled with orphaned data. On larger projects I end up with gobs of keys which end up covering upwards of 8 - 10 layers of data. I want to know if anyone could suggest a graceful way of handling 'expected errors' from the MySQL database in a way that I can construct meaningful messages for the end user. I will explain 'expected errors' with an example. Lets say I have a set of tables used for basic discussions: discussion questions responses users Hierarchically they would probably look something like this: -users --discussion ---questions ----responses When I attempt to delete a user the FKs will check discussions and if any discussion exist the deletion is restricted, deleting discussion checks questions, deleting questions checks responses. An 'expected error' in this case would be attempting to delete a user--unless they are newly created I can anticipate that one or more foreign keys will fail causing an error. What I WANT to do is to catch that error on deletion and be able to tell the end user something like 'We're sorry, but all discussions must be removed before you can delete this user...'. Now I know I can keep and maintain matching arrays in PHP and map specific errors to messages but that is messy and prone to becoming stagnant, or I could manually run a set of selects prior to attempting the deletion, but then I am doing just as much work as without using FKs. Any help here would be greatly appreciated, or if I am just looking at this completely wrong then please let me know. On a side note I generally use CodeIgniter for my application development, so if that would open up an avenue through that framework please consider that in your answers. Thanks in Advance

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  • Javascript - find swfobject on included page and call javascript function

    - by Rob
    I’m using the following script on my website to play an mp3 in flash. To instantiate the flash object I use the swfobject framework in a javascript function. When the function is called the player is created and added to the page. The rest of the website is in php and the page calling this script is being included with the php include function. All the other used scripts are in the php 'master'-page var playerMp3 = new SWFObject("scripts/player.swf","myplayer1","0","0","0"); playerMp3.addVariable("file","track.mp3"); playerMp3.addVariable("icons","false"); playerMp3.write("player1"); var player1 = document.getElementById("myplayer1"); var status1 = $("#status1"); $("#play1").click(function(){ player1.sendEvent("play","true"); $("#status1").fadeIn(400); player4.sendEvent("stop","false"); $("#status4").fadeOut(400); player3.sendEvent("stop","false"); $("#status3").fadeOut(400); player2.sendEvent("stop","false"); $("#status2").fadeOut(400); }); $("#stop1").click(function(){ player1.sendEvent("stop","false"); $("#status1").fadeOut(400); }); $(".closeOver").click(function(){ player1.sendEvent("stop","false"); $("#status1").fadeOut(400); }); $(".accordionButton2").click(function(){ player1.sendEvent("stop","false"); $("#status1").fadeOut(400); }); $(".accordionButton3").click(function(){ player1.sendEvent("stop","false"); $("#status1").fadeOut(400); }); $(".turnOffMusic").click(function(){ player1.sendEvent("stop","false"); $("#status1").fadeOut(400); }); }); I have a play-button with the id ‘#play1’ and a stop-button with the id ‘#stop1’ on my page. A div on the same page has the id ‘#status1’ and a little image of a speaker is in the div. When you push the playbutton, the div with the speaker is fading in and when you push the stopbutton, the div with the speaker is fading out, very simple. And it works as I want it to do. But the problem is, when a song is finished, the speaker doesn’t fade out. Is there a simple solution for this? I already tried using the swfobject framework to get the flash player from the page and call the ‘IsPlaying’ on it, but I’m getting the error that ‘swfobject’ can’t be found. All I need is a little push in the right direction or an example showing me how I can correctly get the currently playing audio player (in flash), check if it’s playing and if finished, call a javascript function to led the speaker-image fade-out again. Hope someone here can help me

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  • Need to lookup function arguments (in/out) from pdb by dbghelp

    - by Usman
    I need to lookup function parameters(their types infact) from PDB file From dbghelp, we can parse any pdb and can get info like how many functions,addresses function names and others etc. My problem is I am also interested to get function parameters as well. As SYMBOL_INFO structure in callback function only contains symbolName,Addresses and Size. How can we lookup PARAMETERES(in/out Types/names)of any function. Regards Usman

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  • Erlang function does not exist in module?

    - by Sepehr Samini
    In lager.elr (the main module of https://github.com/basho/lager) there is no function with name "debug" but I have an application that call debug function from lager module like: lager:debug(Str, Args) I am beginner in Erlang but I know when we call a function from a module lile "mymodule:myfunction" there should be a function with name "myfunction" in file mymodule.erl but in this case when I search in lager.erl for function "debug" I can't find it.

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  • Currying a function n times in Scheme

    - by user1724421
    I'm having trouble figuring out a way to curry a function a specified number of times. That is, I give the function a natural number n and a function fun, and it curries the function n times. For example: (curry n fun) Is the function and a possible application would be: (((((curry 4 +) 1) 2) 3) 4) Which would produce 10. I'm really not sure how to implement it properly. Could someone please give me a hand? Thanks :)

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  • jQuery and function scope

    - by Jason
    Is this: ($.fn.myFunc = function() { var Dennis = function() { /*code */ } $('#Element').click(Dennis); })(); equivalent to: ($.fn.myFunc = function() { $('#Element').click(function() { /*code */ }); })(); If not, can someone please explain the difference, and suggest the better route to take for both performance, function reuse and clarity of reading. Thanks!

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  • PL/SQL function while executing throws Out Process Memory Error

    - by Vinoj Nambiar
    I have PL/SQL function, which is programmed to sort a set of data. This function work fine without any error, when called directly as a PL/SQL Function. However, when I call this Function Via a Unix Shell Script, even though the script returns a success code and throws an Out Process Memory Error and function is actually not executed. I have verified the DB Index spaces and temp spaces, which are more than 50% free spaces

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  • Javascript: Inline function vs predefined functions

    - by glaz666
    Can any body throw me some arguments for using inline functions against passing predefined function name to some handler. I.e. which is better: (function(){ setTimeout(function(){ /*some code here*/ }, 5); })(); versus (function(){ function invokeMe() { /*code*/ } setTimeout(invokeMe, 5); })(); Strange question, but we are almost fighting in the team about this

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  • Javascript unable to pass parameters into a property acting as a function

    - by BOverflow
    Currently in a simplified form, my code looks like this function AddFileParam(file_id, name, value) { uploadcontrol.addFileParam(file_id, name, value) } uploadcontrol = new Upload() function upload() { //logic } upload.prototype.AddFileParam = function(file_id, name, value) { //logic }; The code is giving me an error as it states that addFileParam is not a valid function. This is caused by the instance of the function upload (aka. uploadcontrol). This is only occuring in Firefox/Chrome and not in IE. Any ideas on how to fix this?

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  • calling c function from assembly

    - by void
    I'm trying to use a function in assembly in a C project, the function is supposed to call a libc function let's say printf() but I keep getting a segmentation fault. In the .c file I have the declaration of the function let's say int do_shit_in_asm() In the .asm file I have .extern printf .section .data printtext: .ascii "test" .section .text .global do_shit_in_asm .type do_shit_in_asm, @function do_shit_in_asm: pushl %ebp movl %esp, %ebp push printtext call printf movl %ebp, %esp pop %ebp ret Any pointers would be appreciated. as func.asm -o func.o gcc prog.c func.o -o prog

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  • In Javascript, a function starts a new scope, but we have to be careful that the function must be in

    - by Jian Lin
    In Javascript, I am sometimes too immerged in the idea that a function creates a new scope, that sometimes I even think the following anonymous function will create a new scope when it is being defined and assigned to onclick: <a href="#" id="link1">ha link 1</a> <a href="#" id="link2">ha link 2</a> <a href="#" id="link3">ha link 3</a> <a href="#" id="link4">ha link 4</a> <a href="#" id="link5">ha link 5</a> <script type="text/javascript"> for (i = 1; i <= 5; i++) { document.getElementById('link' + i).onclick = function() { var x = i; alert(x); return false; } } </script> but in fact, the anonymous function will create a new scope, that's right, but ONLY when it is being invoked, is that so? So the x inside the anonymous function is not created, no new scope is created. When the function was later invoked, there is a new scope alright, but the i is in the outside scope, and the x gets its value, and it is all 6 anyways. The following code will actually invoke a function and create a new scope and that's why the x is a new local variable x in the brand new scope each time, and the invocation of the function when the link is clicked on will use the different x in the different scopes. <a href="#" id="link1">ha link 1</a> <a href="#" id="link2">ha link 2</a> <a href="#" id="link3">ha link 3</a> <a href="#" id="link4">ha link 4</a> <a href="#" id="link5">ha link 5</a> <script type="text/javascript"> for (var i = 1; i <= 5; i++) { (function() { var x = i; document.getElementById('link' + i).onclick = function() { alert(x); return false; } })(); // invoking it now! } </script> If we take away the var in front of x, then it is a global x and so no local variable x is created in the new scope, and therefore, clicking on the links get all the same number, which is the value of the global x.

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  • decorating a function and adding functionalities preserving the number of argument

    - by pygabriel
    I'd like to decorate a function, using a pattern like this: def deco(func): def wrap(*a,**kw): print "do something" return func(*a,**kw) return wrap The problem is that if the function decorated has a prototype like that: def function(a,b,c): return When decorated, the prototype is destroyed by the varargs, for example, calling function(1,2,3,4) wouldn't result in an exception. Is that a way to avoid that? How can define the wrap function with the same prototype as the decorated (func) one? There's something conceptually wrong?

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  • Using object's method as callback function for $.post

    - by Kirzilla
    Hello, $.Comment = function() { this.alertme = "Alert!"; } $.Comment.prototype.send = function() { var self = this; $.post( self.url, { 'somedata' : self.somedata }, function(data, self) { self.callback(data); } ); } $.Comment.prototype.callback = function(data) { alert(this.alertme); } When I'm calling $.Comment.send() debugger is saying to me that self.callback(data) is not a function What am I doing wrong? Thank you

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  • slowing down a loop in a recursive function

    - by eco_bach
    I have a difficult problem with a recursive function. Essentially I need to 'slow down' a for loop within a function that repeatedly calls itself(the function); Is this possible, or do I need to somehow extract the recursive nature of the function? function callRecursiveFuncAgain(ob:Object):void{ //do recursive stuff; for (var i:int = 0; i < 4; i++) { _nextObj=foo callRecursiveFuncAgain(_nextObj); } }

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  • Passing function-specific variables

    - by Simon Carlson
    Say I got two functions that looks like this: function main(Index) { doStuff(); } function doStuff() { if(Index == 1) { document.write("Hello world!") } } And some HTML: <input type="button" value="Click me" onclick="main(1)" /> I realize this is a very stupid way to use function-specific variables and such, but it's just out of curiosity. So is it possible to pass the variable Index from the main function to the doStuff function?

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  • a global function for url query

    - by phpExe
    I have written a function: function url_query(){ if (is_numeric($_GET['cmd'])) { $get = $_GET['cmd']; } return $get; } but I want that this function be global. This function works only for eg. index.php?cmd=... Can I revise this function to use for index.php?page=... and index.php?catID=... etc? Thanks

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