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  • Why should I use $[ EXPR ] instead of $(( EXPR ))?

    - by qdii
    On the paragraph explaining arithmetic expansion, Bash's user guide uncovers 2 different ways of evaluating an expression, the first one uses $((?EXPRESSION?)) and the second one uses $[?EXPRESSION?]. The two ways seem pretty similar as the only difference I have found is: $[?EXPRESSION?] will only calculate the result of EXPRESSION, and do no tests: Yet, I am intrigued because the same document recommends using $[?EXPRESSION?] rather than $((?EXPRESSION?)). Wherever possible, Bash users should try to use the syntax with square brackets: Why would you want that if less tests are being done?

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  • Inside the DLR – Invoking methods

    - by Simon Cooper
    So, we’ve looked at how a dynamic call is represented in a compiled assembly, and how the dynamic lookup is performed at runtime. The last piece of the puzzle is how the resolved method gets invoked, and that is the subject of this post. Invoking methods As discussed in my previous posts, doing a full lookup and bind at runtime each and every single time the callsite gets invoked would be far too slow to be usable. The results obtained from the callsite binder must to be cached, along with a series of conditions to determine whether the cached result can be reused. So, firstly, how are the conditions represented? These conditions can be anything; they are determined entirely by the semantics of the language the binder is representing. The binder has to be able to return arbitary code that is then executed to determine whether the conditions apply or not. Fortunately, .NET 4 has a neat way of representing arbitary code that can be easily combined with other code – expression trees. All the callsite binder has to return is an expression (called a ‘restriction’) that evaluates to a boolean, returning true when the restriction passes (indicating the corresponding method invocation can be used) and false when it does’t. If the bind result is also represented in an expression tree, these can be combined easily like so: if ([restriction is true]) { [invoke cached method] } Take my example from my previous post: public class ClassA { public static void TestDynamic() { CallDynamic(new ClassA(), 10); CallDynamic(new ClassA(), "foo"); } public static void CallDynamic(dynamic d, object o) { d.Method(o); } public void Method(int i) {} public void Method(string s) {} } When the Method(int) method is first bound, along with an expression representing the result of the bind lookup, the C# binder will return the restrictions under which that bind can be reused. In this case, it can be reused if the types of the parameters are the same: if (thisArg.GetType() == typeof(ClassA) && arg1.GetType() == typeof(int)) { thisClassA.Method(i); } Caching callsite results So, now, it’s up to the callsite to link these expressions returned from the binder together in such a way that it can determine which one from the many it has cached it should use. This caching logic is all located in the System.Dynamic.UpdateDelegates class. It’ll help if you’ve got this type open in a decompiler to have a look yourself. For each callsite, there are 3 layers of caching involved: The last method invoked on the callsite. All methods that have ever been invoked on the callsite. All methods that have ever been invoked on any callsite of the same type. We’ll cover each of these layers in order Level 1 cache: the last method called on the callsite When a CallSite<T> object is first instantiated, the Target delegate field (containing the delegate that is called when the callsite is invoked) is set to one of the UpdateAndExecute generic methods in UpdateDelegates, corresponding to the number of parameters to the callsite, and the existance of any return value. These methods contain most of the caching, invoke, and binding logic for the callsite. The first time this method is invoked, the UpdateAndExecute method finds there aren’t any entries in the caches to reuse, and invokes the binder to resolve a new method. Once the callsite has the result from the binder, along with any restrictions, it stitches some extra expressions in, and replaces the Target field in the callsite with a compiled expression tree similar to this (in this example I’m assuming there’s no return value): if ([restriction is true]) { [invoke cached method] return; } if (callSite._match) { _match = false; return; } else { UpdateAndExecute(callSite, arg0, arg1, ...); } Woah. What’s going on here? Well, this resulting expression tree is actually the first level of caching. The Target field in the callsite, which contains the delegate to call when the callsite is invoked, is set to the above code compiled from the expression tree into IL, and then into native code by the JIT. This code checks whether the restrictions of the last method that was invoked on the callsite (the ‘primary’ method) match, and if so, executes that method straight away. This means that, the next time the callsite is invoked, the first code that executes is the restriction check, executing as native code! This makes this restriction check on the primary cached delegate very fast. But what if the restrictions don’t match? In that case, the second part of the stitched expression tree is executed. What this section should be doing is calling back into the UpdateAndExecute method again to resolve a new method. But it’s slightly more complicated than that. To understand why, we need to understand the second and third level caches. Level 2 cache: all methods that have ever been invoked on the callsite When a binder has returned the result of a lookup, as well as updating the Target field with a compiled expression tree, stitched together as above, the callsite puts the same compiled expression tree in an internal list of delegates, called the rules list. This list acts as the level 2 cache. Why use the same delegate? Stitching together expression trees is an expensive operation. You don’t want to do it every time the callsite is invoked. Ideally, you would create one expression tree from the binder’s result, compile it, and then use the resulting delegate everywhere in the callsite. But, if the same delegate is used to invoke the callsite in the first place, and in the caches, that means each delegate needs two modes of operation. An ‘invoke’ mode, for when the delegate is set as the value of the Target field, and a ‘match’ mode, used when UpdateAndExecute is searching for a method in the callsite’s cache. Only in the invoke mode would the delegate call back into UpdateAndExecute. In match mode, it would simply return without doing anything. This mode is controlled by the _match field in CallSite<T>. The first time the callsite is invoked, _match is false, and so the Target delegate is called in invoke mode. Then, if the initial restriction check fails, the Target delegate calls back into UpdateAndExecute. This method sets _match to true, then calls all the cached delegates in the rules list in match mode to try and find one that passes its restrictions, and invokes it. However, there needs to be some way for each cached delegate to inform UpdateAndExecute whether it passed its restrictions or not. To do this, as you can see above, it simply re-uses _match, and sets it to false if it did not pass the restrictions. This allows the code within each UpdateAndExecute method to check for cache matches like so: foreach (T cachedDelegate in Rules) { callSite._match = true; cachedDelegate(); // sets _match to false if restrictions do not pass if (callSite._match) { // passed restrictions, and the cached method was invoked // set this delegate as the primary target to invoke next time callSite.Target = cachedDelegate; return; } // no luck, try the next one... } Level 3 cache: all methods that have ever been invoked on any callsite with the same signature The reason for this cache should be clear – if a method has been invoked through a callsite in one place, then it is likely to be invoked on other callsites in the codebase with the same signature. Rather than living in the callsite, the ‘global’ cache for callsite delegates lives in the CallSiteBinder class, in the Cache field. This is a dictionary, typed on the callsite delegate signature, providing a RuleCache<T> instance for each delegate signature. This is accessed in the same way as the level 2 callsite cache, by the UpdateAndExecute methods. When a method is matched in the global cache, it is copied into the callsite and Target cache before being executed. Putting it all together So, how does this all fit together? Like so (I’ve omitted some implementation & performance details): That, in essence, is how the DLR performs its dynamic calls nearly as fast as statically compiled IL code. Extensive use of expression trees, compiled to IL and then into native code. Multiple levels of caching, the first of which executes immediately when the dynamic callsite is invoked. And a clever re-use of compiled expression trees that can be used in completely different contexts without being recompiled. All in all, a very fast and very clever reflection caching mechanism.

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  • JsTree v1.0 - How to manipulate effectively the data from the backend to render the trees and operate correctly?

    - by Jean Paul
    Backend info: PHP 5 / MySQL URL: http://github.com/downloads/vakata/jstree/jstree_pre1.0_fix_1.zip Table structure for table discussions_tree -- CREATE TABLE IF NOT EXISTS `discussions_tree` ( `id` int(11) NOT NULL AUTO_INCREMENT, `parent_id` int(11) NOT NULL DEFAULT '0', `user_id` int(11) NOT NULL DEFAULT '0', `label` varchar(16) DEFAULT NULL, `position` bigint(20) unsigned NOT NULL DEFAULT '0', `left` bigint(20) unsigned NOT NULL DEFAULT '0', `right` bigint(20) unsigned NOT NULL DEFAULT '0', `level` bigint(20) unsigned NOT NULL DEFAULT '0', `type` varchar(255) CHARACTER SET utf8 COLLATE utf8_unicode_ci DEFAULT NULL, `h_label` varchar(16) NOT NULL DEFAULT '', `fulllabel` varchar(255) DEFAULT NULL, UNIQUE KEY `uidx_3` (`id`), KEY `idx_1` (`user_id`), KEY `idx_2` (`parent_id`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=8 ; /*The first element should in my understanding not even be shown*/ INSERT INTO `discussions_tree` (`id`, `parent_id`, `user_id`, `label`, `position`, `left`, `right`, `level`, `type`, `h_label`, `fulllabel`) VALUES (0, 0, 0, 'Contacts', 0, 1, 1, 0, NULL, '', NULL); INSERT INTO `discussions_tree` (`id`, `parent_id`, `user_id`, `label`, `position`, `left`, `right`, `level`, `type`, `h_label`, `fulllabel`) VALUES (1, 0, 0, 'How to Tag', 1, 2, 2, 0, 'drive', '', NULL); Front End : I've simplified the logic, it has 6 trees actually inside of a panel and that works fine $array = array("Discussions"); $id_arr = array("d"); $nid = 0; foreach ($array as $k=> $value) { $nid++; ?> <li id="<?=$value?>" class="label"> <a href='#<?=$value?>'><span> <?=$value?> </span></a> <div class="sub-menu" style="height:auto; min-height:120px; background-color:#E5E5E5" > <div class="menu" id="menu_<?=$id_arr[$k]?>" style="position:relative; margin-left:56%"> <img src="./js/jsTree/create.png" alt="" id="create" title="Create" > <img src="./js/jsTree/rename.png" alt="" id="rename" title="Rename" > <img src="./js/jsTree/remove.png" alt="" id="remove" title="Delete"> <img src="./js/jsTree/cut.png" alt="" id="cut" title="Cut" > <img src="./js/jsTree/copy.png" alt="" id="copy" title="Copy"> <img src="./js/jsTree/paste.png" alt="" id="paste" title="Paste"> </div> <div id="<?=$id_arr[$k]?>" class="jstree_container"></div> </div> </li> <!-- JavaScript neccessary for this tree : <?=$value?> --> <script type="text/javascript" > jQuery(function ($) { $("#<?=$id_arr[$k]?>").jstree({ // List of active plugins used "plugins" : [ "themes", "json_data", "ui", "crrm" , "hotkeys" , "types" , "dnd", "contextmenu"], // "ui" :{ "initially_select" : ["#node_"+ $nid ] } , "crrm": { "move": { "always_copy": "multitree" }, "input_width_limit":128 }, "core":{ "strings":{ "new_node" : "New Tag" }}, "themes": {"theme": "classic"}, "json_data" : { "ajax" : { "url" : "./js/jsTree/server-<?=$id_arr[$k]?>.php", "data" : function (n) { // the result is fed to the AJAX request `data` option return { "operation" : "get_children", "id" : n.attr ? n.attr("id").replace("node_","") : 1, "state" : "", "user_id": <?=$uid?> }; } } } , "types" : { "max_depth" : -1, "max_children" : -1, "types" : { // The default type "default" : { "hover_node":true, "valid_children" : [ "default" ], }, // The `drive` nodes "drive" : { // can have files and folders inside, but NOT other `drive` nodes "valid_children" : [ "default", "folder" ], "hover_node":true, "icon" : { "image" : "./js/jsTree/root.png" }, // those prevent the functions with the same name to be used on `drive` nodes.. internally the `before` event is used "start_drag" : false, "move_node" : false, "remove_node" : false } } }, "contextmenu" : { "items" : customMenu , "select_node": true} }) //Hover function binded to jstree .bind("hover_node.jstree", function (e, data) { $('ul li[rel="drive"], ul li[rel="default"], ul li[rel=""]').each(function(i) { $(this).find("a").attr('href', $(this).attr("id")+".php" ); }) }) //Create function binded to jstree .bind("create.jstree", function (e, data) { $.post( "./js/jsTree/server-<?=$id_arr[$k]?>.php", { "operation" : "create_node", "id" : data.rslt.parent.attr("id").replace("node_",""), "position" : data.rslt.position, "label" : data.rslt.name, "href" : data.rslt.obj.attr("href"), "type" : data.rslt.obj.attr("rel"), "user_id": <?=$uid?> }, function (r) { if(r.status) { $(data.rslt.obj).attr("id", "node_" + r.id); } else { $.jstree.rollback(data.rlbk); } } ); }) //Remove operation .bind("remove.jstree", function (e, data) { data.rslt.obj.each(function () { $.ajax({ async : false, type: 'POST', url: "./js/jsTree/server-<?=$id_arr[$k]?>.php", data : { "operation" : "remove_node", "id" : this.id.replace("node_",""), "user_id": <?=$uid?> }, success : function (r) { if(!r.status) { data.inst.refresh(); } } }); }); }) //Rename operation .bind("rename.jstree", function (e, data) { data.rslt.obj.each(function () { $.ajax({ async : true, type: 'POST', url: "./js/jsTree/server-<?=$id_arr[$k]?>.php", data : { "operation" : "rename_node", "id" : this.id.replace("node_",""), "label" : data.rslt.new_name, "user_id": <?=$uid?> }, success : function (r) { if(!r.status) { data.inst.refresh(); } } }); }); }) //Move operation .bind("move_node.jstree", function (e, data) { data.rslt.o.each(function (i) { $.ajax({ async : false, type: 'POST', url: "./js/jsTree/server-<?=$id_arr[$k]?>.php", data : { "operation" : "move_node", "id" : $(this).attr("id").replace("node_",""), "ref" : data.rslt.cr === -1 ? 1 : data.rslt.np.attr("id").replace("node_",""), "position" : data.rslt.cp + i, "label" : data.rslt.name, "copy" : data.rslt.cy ? 1 : 0, "user_id": <?=$uid?> }, success : function (r) { if(!r.status) { $.jstree.rollback(data.rlbk); } else { $(data.rslt.oc).attr("id", "node_" + r.id); if(data.rslt.cy && $(data.rslt.oc).children("UL").length) { data.inst.refresh(data.inst._get_parent(data.rslt.oc)); } } } }); }); }); // This is for the context menu to bind with operations on the right clicked node function customMenu(node) { // The default set of all items var control; var items = { createItem: { label: "Create", action: function (node) { return {createItem: this.create(node) }; } }, renameItem: { label: "Rename", action: function (node) { return {renameItem: this.rename(node) }; } }, deleteItem: { label: "Delete", action: function (node) { return {deleteItem: this.remove(node) }; }, "separator_after": true }, copyItem: { label: "Copy", action: function (node) { $(node).addClass("copy"); return {copyItem: this.copy(node) }; } }, cutItem: { label: "Cut", action: function (node) { $(node).addClass("cut"); return {cutItem: this.cut(node) }; } }, pasteItem: { label: "Paste", action: function (node) { $(node).addClass("paste"); return {pasteItem: this.paste(node) }; } } }; // We go over all the selected items as the context menu only takes action on the one that is right clicked $.jstree._reference("#<?=$id_arr[$k]?>").get_selected(false, true).each(function(index,element) { if ( $(element).attr("id") != $(node).attr("id") ) { // Let's deselect all nodes that are unrelated to the context menu -- selected but are not the one right clicked $("#<?=$id_arr[$k]?>").jstree("deselect_node", '#'+$(element).attr("id") ); } }); //if any previous click has the class for copy or cut $("#<?=$id_arr[$k]?>").find("li").each(function(index,element) { if ($(element) != $(node) ) { if( $(element).hasClass("copy") || $(element).hasClass("cut") ) control=1; } else if( $(node).hasClass("cut") || $(node).hasClass("copy")) { control=0; } }); //only remove the class for cut or copy if the current operation is to paste if($(node).hasClass("paste") ) { control=0; // Let's loop through all elements and try to find if the paste operation was done already $("#<?=$id_arr[$k]?>").find("li").each(function(index,element) { if( $(element).hasClass("copy") ) $(this).removeClass("copy"); if ( $(element).hasClass("cut") ) $(this).removeClass("cut"); if ( $(element).hasClass("paste") ) $(this).removeClass("paste"); }); } switch (control) { //Remove the paste item from the context menu case 0: switch ($(node).attr("rel")) { case "drive": delete items.renameItem; delete items.deleteItem; delete items.cutItem; delete items.copyItem; delete items.pasteItem; break; case "default": delete items.pasteItem; break; } break; //Remove the paste item from the context menu only on the node that has either copy or cut added class case 1: if( $(node).hasClass("cut") || $(node).hasClass("copy") ) { switch ($(node).attr("rel")) { case "drive": delete items.renameItem; delete items.deleteItem; delete items.cutItem; delete items.copyItem; delete items.pasteItem; break; case "default": delete items.pasteItem; break; } } else //Re-enable it on the clicked node that does not have the cut or copy class { switch ($(node).attr("rel")) { case "drive": delete items.renameItem; delete items.deleteItem; delete items.cutItem; delete items.copyItem; break; } } break; //initial state don't show the paste option on any node default: switch ($(node).attr("rel")) { case "drive": delete items.renameItem; delete items.deleteItem; delete items.cutItem; delete items.copyItem; delete items.pasteItem; break; case "default": delete items.pasteItem; break; } break; } return items; } $("#menu_<?=$id_arr[$k]?> img").hover( function () { $(this).css({'cursor':'pointer','outline':'1px double teal'}) }, function () { $(this).css({'cursor':'none','outline':'1px groove transparent'}) } ); $("#menu_<?=$id_arr[$k]?> img").click(function () { switch(this.id) { //Create only the first element case "create": if ( $.jstree._reference("#<?=$id_arr[$k]?>").get_selected(false, true).length ) { $.jstree._reference("#<?=$id_arr[$k]?>").get_selected(false, true).each(function(index,element){ switch(index) { case 0: $("#<?=$id_arr[$k]?>").jstree("create", '#'+$(element).attr("id"), null, /*{attr : {href: '#' }}*/null ,null, false); break; default: $("#<?=$id_arr[$k]?>").jstree("deselect_node", '#'+$(element).attr("id") ); break; } }); } else { $.facebox('<p class=\'p_inner error bold\'>A selection needs to be made to work with this operation'); setTimeout(function(){ $.facebox.close(); }, 2000); } break; //REMOVE case "remove": if ( $.jstree._reference("#<?=$id_arr[$k]?>").get_selected(false, true).length ) { $.jstree._reference("#<?=$id_arr[$k]?>").get_selected(false, true).each(function(index,element){ //only execute if the current node is not the first one (drive) if( $(element).attr("id") != $("div.jstree > ul > li").first().attr("id") ) { $("#<?=$id_arr[$k]?>").jstree("remove",'#'+$(element).attr("id")); } else $("#<?=$id_arr[$k]?>").jstree("deselect_node", '#'+$(element).attr("id") ); }); } else { $.facebox('<p class=\'p_inner error bold\'>A selection needs to be made to work with this operation'); setTimeout(function(){ $.facebox.close(); }, 2000); } break; //RENAME NODE only one selection case "rename": if ( $.jstree._reference("#<?=$id_arr[$k]?>").get_selected(false, true).length ) { $.jstree._reference("#<?=$id_arr[$k]?>").get_selected(false, true).each(function(index,element){ if( $(element).attr("id") != $("div.jstree > ul > li").first().attr("id") ) { switch(index) { case 0: $("#<?=$id_arr[$k]?>").jstree("rename", '#'+$(element).attr("id") ); break; default: $("#<?=$id_arr[$k]?>").jstree("deselect_node", '#'+$(element).attr("id") ); break; } } else $("#<?=$id_arr[$k]?>").jstree("deselect_node", '#'+$(element).attr("id") ); }); } else { $.facebox('<p class=\'p_inner error bold\'>A selection needs to be made to work with this operation'); setTimeout(function(){ $.facebox.close(); }, 2000); } break; //Cut case "cut": if ( $.jstree._reference("#<?=$id_arr[$k]?>").get_selected(false, true).length ) { $.jstree._reference("#<?=$id_arr[$k]?>").get_selected(false, true).each(function(index,element){ switch(index) { case 0: $("#<?=$id_arr[$k]?>").jstree("cut", '#'+$(element).attr("id")); $.facebox('<p class=\'p_inner teal\'>Operation "Cut" successfully done.<p class=\'p_inner teal bold\'>Where to place it?'); setTimeout(function(){ $.facebox.close(); $("#<?=$id_arr[$k]?>").jstree("deselect_node", '#'+$(element).attr("id")); }, 2000); break; default: $("#<?=$id_arr[$k]?>").jstree("deselect_node", '#'+$(element).attr("id") ); break; } }); } else { $.facebox('<p class=\'p_inner error bold\'>A selection needs to be made to work with this operation'); setTimeout(function(){ $.facebox.close(); }, 2000); } break; //Copy case "copy": if ( $.jstree._reference("#<?=$id_arr[$k]?>").get_selected(false, true).length ) { $.jstree._reference("#<?=$id_arr[$k]?>").get_selected(false, true).each(function(index,element){ switch(index) { case 0: $("#<?=$id_arr[$k]?>").jstree("copy", '#'+$(element).attr("id")); $.facebox('<p class=\'p_inner teal\'>Operation "Copy": Successfully done.<p class=\'p_inner teal bold\'>Where to place it?'); setTimeout(function(){ $.facebox.close(); $("#<?=$id_arr[$k]?>").jstree("deselect_node", '#'+$(element).attr("id") ); }, 2000); break; default: $("#<?=$id_arr[$k]?>").jstree("deselect_node", '#'+$(element).attr("id") ); break; } }); } else { $.facebox('<p class=\'p_inner error bold\'>A selection needs to be made to work with this operation'); setTimeout(function(){ $.facebox.close(); }, 2000); } break; case "paste": if ( $.jstree._reference("#<?=$id_arr[$k]?>").get_selected(false, true).length ) { $.jstree._reference("#<?=$id_arr[$k]?>").get_selected(false, true).each(function(index,element){ switch(index) { case 0: $("#<?=$id_arr[$k]?>").jstree("paste", '#'+$(element).attr("id")); break; default: $("#<?=$id_arr[$k]?>").jstree("deselect_node", '#'+$(element).attr("id") ); break; } }); } else { $.facebox('<p class=\'p_inner error bold\'>A selection needs to be made to work with this operation'); setTimeout(function(){ $.facebox.close(); }, 2000); } break; } }); <? } ?> server.php $path='../../../..'; require_once "$path/phpfoo/dbif.class"; require_once "$path/global.inc"; // Database config & class $db_config = array( "servername"=> $dbHost, "username" => $dbUser, "password" => $dbPW, "database" => $dbName ); if(extension_loaded("mysqli")) require_once("_inc/class._database_i.php"); else require_once("_inc/class._database.php"); //Tree class require_once("_inc/class.ctree.php"); $dbLink = new dbif(); $dbErr = $dbLink->connect($dbName,$dbUser,$dbPW,$dbHost); $jstree = new json_tree(); if(isset($_GET["reconstruct"])) { $jstree->_reconstruct(); die(); } if(isset($_GET["analyze"])) { echo $jstree->_analyze(); die(); } $table = '`discussions_tree`'; if($_REQUEST["operation"] && strpos($_REQUEST["operation"], "_") !== 0 && method_exists($jstree, $_REQUEST["operation"])) { foreach($_REQUEST as $k => $v) { switch($k) { case 'user_id': //We are passing the user_id from the $_SESSION on each request and trying to pick up the min and max value from the table that matches the 'user_id' $sql = "SELECT max(`right`) , min(`left`) FROM $table WHERE `user_id`=$v"; //If the select does not return any value then just let it be :P if (!list($right, $left)=$dbLink->getRow($sql)) { $sql = $dbLink->dbSubmit("UPDATE $table SET `user_id`=$v WHERE `id` = 1 AND `parent_id` = 0"); $sql = $dbLink->dbSubmit("UPDATE $table SET `user_id`=$v WHERE `parent_id` = 1 AND `label`='How to Tag' "); } else { $sql = $dbLink->dbSubmit("UPDATE $table SET `user_id`=$v, `right`=$right+2 WHERE `id` = 1 AND `parent_id` = 0"); $sql = $dbLink->dbSubmit("UPDATE $table SET `user_id`=$v, `left`=$left+1, `right`=$right+1 WHERE `parent_id` = 1 AND `label`='How to Tag' "); } break; } } header("HTTP/1.0 200 OK"); header('Content-type: application/json; charset=utf-8'); header("Cache-Control: no-cache, must-revalidate"); header("Expires: Mon, 26 Jul 1997 05:00:00 GMT"); header("Pragma: no-cache"); echo $jstree->{$_REQUEST["operation"]}($_REQUEST); die(); } header("HTTP/1.0 404 Not Found"); ?> The problem: DND *(Drag and Drop) works, Delete works, Create works, Rename works, but Copy, Cut and Paste don't work

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  • Regular expression to validate name n language other then english like Spanish..

    - by BT
    Hi, how can i write a regular expression to validate name field in a multilingual web application, i want to validate the name field for non-English languages e.g. Spanish or German, and we need to make sure that no one enter digits or special characters. I'm using .NET. I believe we can't use expression as below for non-English language. ^[a-zA-Z]{1,20}$ Any help will be highly appreciated!

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  • How do you make a regular expression that matches a word with one randomly inserted character?

    - by Dfowj
    Hey all, i want to use a regular expression to match a word with one specified character randomly placed within it. I also want to keep that 'base' word's characters in their original order. For example, with the 'base' word of test and the specified character of 'y', i want the regular expression to match all the following, and ONLY the following: ytest, tyest, teyst, tesyt, testy Incase it matters, im working in javascript and using the dojo toolkit. Thanks!

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  • How To? Use an Expression Tree to call a Generic Method when the Type is only known at runtime.

    - by David Williams
    Please bear with me; I am very new to expression trees and lambda expressions, but trying to learn. This is something that I solved using reflection, but would like to see how to do it using expression trees. I have a generic function: private void DoSomeThing<T>( param object[] args ) { // Some work is done here. } that I need to call from else where in my class. Now, normally, this would be be simple: DoSomeThing<int>( blah ); but only if I know, at design time that I am working with an int. When I do not know the type until runtime is where I need the help. Like I said, I know how to do it via reflection, but I would like to do it via expression trees, as my (very limited) understanding is that I can do so. Any suggestions or points to sites where I can get this understanding, preferably with sample code?

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  • .Net lambda expression-- where did this parameter come from?

    - by larryq
    I'm a lambda newbie, so if I'm missing vital information in my description please tell me. I'll keep the example as simple as possible. I'm going over someone else's code and they have one class inheriting from another. Here's the derived class first, along with the lambda expression I'm having trouble understanding: class SampleViewModel : ViewModelBase { private ICustomerStorage storage = ModelFactory<ICustomerStorage>.Create(); public ICustomer CurrentCustomer { get { return (ICustomer)GetValue(CurrentCustomerProperty); } set { SetValue(CurrentCustomerProperty, value); } } private int quantitySaved; public int QuantitySaved { get { return quantitySaved; } set { if (quantitySaved != value) { quantitySaved = value; NotifyPropertyChanged(p => QuantitySaved); //where does 'p' come from? } } } public static readonly DependencyProperty CurrentCustomerProperty; static SampleViewModel() { CurrentCustomerProperty = DependencyProperty.Register("CurrentCustomer", typeof(ICustomer), typeof(SampleViewModel), new UIPropertyMetadata(ModelFactory<ICustomer>.Create())); } //more method definitions follow.. Note the call to NotifyPropertyChanged(p => QuantitySaved) bit above. I don't understand where the "p" is coming from. Here's the base class: public abstract class ViewModelBase : DependencyObject, INotifyPropertyChanged, IXtremeMvvmViewModel { public event PropertyChangedEventHandler PropertyChanged; protected virtual void NotifyPropertyChanged<T>(Expression<Func<ViewModelBase, T>> property) { MvvmHelper.NotifyPropertyChanged(property, PropertyChanged); } } There's a lot in there that's not germane to the question I'm sure, but I wanted to err on the side of inclusiveness. The problem is, I don't understand where the 'p' parameter is coming from, and how the compiler knows to (evidently?) fill in a type value of ViewModelBase from thin air? For fun I changed the code from 'p' to 'this', since SampleViewModel inherits from ViewModelBase, but I was met with a series of compiler errors, the first one of which statedInvalid expression term '=>' This confused me a bit since I thought that would work. Can anyone explain what's happening here?

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  • How to detect what allowed character in current Regular Expression by using JavaScript?

    - by Soul_Master
    In my web application, I create some framework that use to bind model data to control on page. Each model property has some rule like string length, not null and regular expression. Before submit page, framework validate any binded control with defined rules. So, I want to detect what character that is allowed in each regular expression rule like the following example. "^[0-9]$" allow only digit characters like 1, 2, 3. "^[a-zA-Z_][a-zA-Z_-0-9]+$" allow only a-z, - and _ characters However, this function should not care about grouping, positioning of allowed character. It just tells about possible characters only. By the way, complex regular expression like find two words near(\bword1\W+(?:\w+\W+){1,6}?word2\b) must be ignore to verify and it should return any characters is possible. Do you have any idea for creating this function? PS. I know it easy to create specified function like numeric only for allowing only digit characters. But I need share/reuse same piece of code both data tier(contains all model validator) and UI tier without modify anything. Thanks

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  • What is the best way to add and order to Doctrine Nested Set Trees?

    - by murze
    What is the best way to add a sense of order in Doctrine Nested Sets? The documention contains several examples of how to get al the childeren of a specific node $category->getNode()->getSiblings() But how can I for example: change the position of the fourth sibling to the second position get only the second sibling add a sibling between the second and third child etc... Do I have to manually add and ordercolumn to the model to do these operations?

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  • Are there any radix/patricia/critbit trees for Python?

    - by Andrew Dalke
    I have about 10,000 words used as a set of inverted indices to about 500,000 documents. Both are normalized so the index is a mapping of integers (word id) to a set of integers (ids of documents which contain the word). My prototype uses Python's set as the obvious data type. When I do a search for a document I find the list of N search words and their corresponding N sets. I want to return the set of documents in the intersection of those N sets. Python's "intersect" method is implemented as a pairwise reduction. I think I can do better with a parallel search of sorted sets, so long as the library offers a fast way to get the next entry after i. I've been looking for something like that for some time. Years ago I wrote PyJudy but I no longer maintain it and I know how much work it would take to get it to a stage where I'm comfortable with it again. I would rather use someone else's well-tested code, and I would like one which supports fast serialization/deserialization. I can't find any, or at least not any with Python bindings. There is avltree which does what I want, but since even the pair-wise set merge take longer than I want, I suspect I want to have all my operations done in C/C++. Do you know of any radix/patricia/critbit tree libraries written as C/C++ extensions for Python? Failing that, what is the most appropriate library which I should wrap? The Judy Array site hasn't been updated in 6 years, with 1.0.5 released in May 2007. (Although it does build cleanly so perhaps It Just Works.)

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  • Any tips of how to handle hierarchical trees in relational model?

    - by George
    Hello all. I have a tree structure that can be n-levels deep, without restriction. That means that each node can have another n nodes. What is the best way to retrieve a tree like that without issuing thousands of queries to the database? I looked at a few other models, like flat table model, Preorder Tree Traversal Algorithm, and so. Do you guys have any tips or suggestions of how to implement a efficient tree model? My objective in the real end is to have one or two queries that would spit the whole tree for me. With enough processing i can display the tree in dot net, but that would be in client machine, so, not much of a big deal. Thanks for the attention

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  • Any tips of how to handle hierarchial trees in relational model?

    - by George
    Hello all. I have a tree structure that can be n-levels deep, without restriction. That means that each node can have another n nodes. What is the best way to retrieve a tree like that without issuing thousands of queries to the database? I looked at a few other models, like flat table model, Preorder Tree Traversal Algorithm, and so. Do you guys have any tips or suggestions of how to implement a efficient tree model? My objective in the real end is to have one or two queries that would spit the whole tree for me. With enough processing i can display the tree in dot net, but that would be in client machine, so, not much of a big deal. Thanks for the attention

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  • Which is more maintainable -- boolean assignment via if/else or boolean expression?

    - by Bret Walker
    Which would be considered more maintainable? if (a == b) c = true; else c = false; or c = (a == b); I've tried looking in Code Complete, but can't find an answer. I think the first is more readable (you can literally read it out loud), which I also think makes it more maintainable. The second one certainly makes more sense and reduces code, but I'm not sure it's as maintainable for C# developers (I'd expect to see this idiom more in, for example, Python).

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  • Python 3.4 adds re.fullmatch()

    - by Jan Goyvaerts
    Python 3.4 does not bring any changes to its regular expression syntax compared to previous 3.x releases. It does add one new function to the re module called fullmatch(). This function takes a regular expression and a subject string as its parameters. It returns True if the regular expression can match the string entirely. It returns False if the string cannot be matched or if it can only be matched partially. This is useful when using a regular expression to validate user input. Do note that fullmatch() will return True if the subject string is the empty string and the regular expression can find zero-length matches. A zero-length match of a zero-length string is a complete match. So if you want to check whether the user entered a sequence of digits, use \d+ rather than \d* as the regex.

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  • Regular Expression for any number divisible by 60 using C# .Net ?

    - by Steve Johnson
    Hi there, I need to apply validation on input time intervals that are taken in as seconds. Now i am not really good at Regular expressions. So can any body help making a regular expression that can test whether a number is divisible by 60. I was wondering if i could use to test one that check that the number is divisible by 10 and then check whether the same is divisible by 6. For number divisible by 10 here [\d*0] is the expression i guess. Please correct me if i am wrong. Hope somebody solves my problem. Thanks

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  • Spatial Index for Rectangles With Fast Insert

    - by TheCloudlessSky
    Hello, I'm looking for a data structure that provides indexing for Rectangles. I need the insert algorithm to be as fast as possible since the rectangles will be moving around the screen (think of dragging a rectangle with your mouse to a new position). I've looked into R-Trees, R+Trees, kD-Trees, Quad-Trees and B-Trees but from my understanding insert's are usually slow. I'd prefer to have inserts at sub-linear time complexity so maybe someone can prove me wrong about either of the listed data structures. I should be able to query the data structure for what rectangles are at point(x, y) or what rectangles intersect rectangle(x, y, width, height). EDIT: The reason I want insert so fast is because if you think of a rectangle being moved around the screen, they're going to have to be removed and then re-inserted. Thanks!

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  • List of fundamental data structures - what am I missing?

    - by jboxer
    I've been studying my fundamental data structures a bunch recently, trying to make sure I've got them down cold. By "fundamental", I mean the real basic ones. Fancy ones like Red-Black Trees and Bloom Filters are clearly worth knowing, but they're usually either enhancements of fundamental ones (Red-Black Trees are binary search trees with special properties to keep them balanced) or they're only useful in very specific situations (Bloom Filters). So far, I'm "fluent" in the following data structures: Arrays Linked Lists Stacks/Queues Binary Search Trees Heaps/Priority Queues Hash Tables However, I feel like I'm missing something. Are there any fundamental ones that I'm forgetting about? EDIT: Added these after posting the question Strings (suggested by catchmeifyoutry) Sets (suggested by Peter) Graphs (suggested by Nick D and aJ) B-Trees (Suggested by tloach) I'm a little on-the-fence about whether these are too fancy or not, but I think they're different enough from the fundamental structures (and important enough) to be worth studying as fundamental.

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  • Can a repeated piece of regular expression create multiple groups? Such as this example...

    - by Yousui
    Hi guys, I'm using RUBY 's regular expression to deal with text such as ${1:aaa|bbbb} ${233:aaa | bbbb | ccc ccccc } ${34: aaa | bbbb | cccccccc |d} ${343: aaa | bbbb | cccccccc |dddddd ddddddddd} ${3443:a aa|bbbb|cccccccc|d} ${353:aa a| b b b b | c c c c c c c c | dddddd} I want to get the trimed text between each pipe line. For example, for the first line of my upper example, I want to get the result aaa and bbbb, for the second line, I want aaa, bbbb and ccc ccccc. Now I have wrote a piece of regular expression and a piece of ruby code to test it: array = "${33:aaa|bbbb|cccccccc}".scan(/\$\{\s*(\d+)\s*:(\s*[^\|]+\s*)(?:\|(\s*[^\|]+\s*))+\}/) puts array Now my problem is the (?:\|(\s*[^\|]+\s*))+ part can't create multiple groups. I don't know how to solve this problem, because the number of text I need in each line is variable. Anyone can help? Great thanks.

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  • What is the MM/DD/YYYY regular expression and how do I use it in php?

    - by zeckdude
    I found the regular expression for MM/DD/YYYY at http://www.regular-expressions.info/regexbuddy/datemmddyyyy.html but I don't think I am using it correctly. Here's my code: $date_regex = '(0[1-9]|1[012])[- /.](0[1-9]|[12][0-9]|3[01])[- /.](19|20)\d\d'; $test_date = '03/22/2010'; if(preg_match($date_regex, $test_date)) { echo 'this date is formatted correctly'; } else { echo 'this date is not formatted correctly'; } When I run this, it still echoes 'this date is not formatted correctly', when it should be saying the opposite. How do I set this regular expression up in php?

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