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  • Flex Tree leaf-element highlighting while drag&drop

    - by sani4xl
    Hi, i have TileList from which i'm dragging some stuff(image) to Tree (something like dragging sounds into playlist in iTunes), but when i can drop this stuff, i see only underline, this mean i can drop it only under or above some leaf-element in that Tree. How can i force it to hide this black underline and highlight leaf-element to which i wanna drop my stuff. Thanks

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  • Tree data structure gems compared?

    - by huug
    I want to you use a tree structure for my navigation. I was thinking about using Ancestry, but then I found this article about 7 plugins for providing a tree structure to your models. What are the pros/cons for each plugin/gem and above all: which one do you recommend? Tnx!

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  • Estimating the size of a tree

    - by Full Decent
    I'd like to estimate the number of leaves in a large tree structure for which I can't visit every node exhaustively. Is this algorithm appropriate? Does it have a name? Also, please pedant if I am using any terms improperly. sum_trials = 0 num_trials = 0 WHILE time_is_not_up bits = 0 ptr = tree.root WHILE count(ptr.children) > 0 bits += log2(count(ptr.children)) ptr = ptr.children[rand()%count(ptr.children)] sum_trials += bits num_trials++ estimated_tree_size = 2^(sum_trials/num_trials)

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  • POV Christmas Tree Is a Holiday-Themed DIY Electronics Project

    - by Jason Fitzpatrick
    If you’re looking for an electronics project with a bit of holiday cheer, this clever POV Christmas tree combines LEDs, motors, and a simple vision hack to create a glowing Christmas tree. POV (or Persistence Of Vision) hacks rely on your visual circuit’s lag time. By taking advantage of that lag POV displays can create the illusion of shapes and words where there are none. In the case of this Christmas tree hack a spinning set of LED lights creates the illusion of a Christmas tree when, in reality, there is just a few LEDs suspended in space by wire. It’s not a beginner level project by any means but it is a great way to practice surface mounting electronics and polish up your PCB making skills. Hit up the link below for the full tutorial. POV Christmas Tree [Instructables] HTG Explains: Do You Really Need to Defrag Your PC? Use Amazon’s Barcode Scanner to Easily Buy Anything from Your Phone How To Migrate Windows 7 to a Solid State Drive

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  • Beyond Syntax Highlighting - What other code representations are possible today?

    - by Mathieu Hélie
    Despite GUI applications having been around for 30ish years, software is still written as lines of text instructions, for various valid reasons. But we've also found that manipulating these text instructions is mind-blowingly difficult unless we apply a layer of coloring on different words to represent their syntax, thus allowing us to quickly parse through these text files without having to read the whole words. But besides the Sublime Text minimap feature, I've yet to see any innovation in visual representation of code since colors came around on CRT monitors. I can think of one obviously essential representation that modern graphics technology allows: visual hierarchies for nested structures. If we make nested text slightly smaller than its outer context, and zoom on it when the cursor is focused on the line, then we will be able to browse huge files of nested statements very quickly. This becomes even more essential as languages based on closures and anonymous functions become filled with deep statements. Has anyone attempted to implement this in a text editor? Do you know of any otherwise useful improvements in representing code text graphically?

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  • Why isn't functional language syntax more close to human language?

    - by JohnDoDo
    I'm interested in functional programming and decided to get head to head with Haskell. My head hurts... but I'll eventually get it... I have one curiosity though, why is the syntax so cryptic (in lack of another word)? Is there a reason why it isn't more expressive, more close to human language? I understand that FP is good at modelling mathematical concepts and it borrowed some of it's concise means of expression, but still it's not math... it's a language.

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  • dijit tree and focus node

    - by user220836
    Hello, I cannot get focusNode() or expandNode() get working. I also tried switching back to dojo 1.32 and even 1.3, no difference to 1.4. And I debugged with firebug, the node is a valid tree node and no errors occur but the node wont get focused. Help is VERY appreciated! <head> <script type="text/javascript"> dojo.declare("itcTree",[dijit.Tree], { focusNodeX : function(/* string */ id) { var node=this._itemNodesMap[id]; this.focusNode(node); } }); </script> </head> <body class="tundra"> <div dojoType="dojo.data.ItemFileReadStore" jsId="continentStore" url="countries.json"> </div> <div dojoType="dijit.tree.ForestStoreModel" jsId="continentModel" store="continentStore" query="{type:'continent'}" rootId="continentRoot" rootLabel="Continents" childrenAttrs="children"> </div> <div dojoType="itcTree" id="mytree" model="continentModel" openOnClick="true"> <script type="dojo/method" event="onClick" args="item"> dijit.byId('mytree').focusNodeX('AF'); </script> </div> <p> <button onclick="dijit.byId('mytree').focusNode('DE');">klick</button> </p> </body>

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  • Parsing an arithmetic expression and building a tree from it in Java

    - by ChocolateBear
    Hi, I needed some help with creating custom trees given an arithmetic expression. Say, for example, you input this arithmetic expression: (5+2)*7 The result tree should look like: * / \ + 7 / \ 5 2 I have some custom classes to represent the different types of nodes, i.e. PlusOp, LeafInt, etc. I don't need to evaluate the expression, just create the tree, so I can perform other functions on it later. Additionally, the negative operator '-' can only have one child, and to represent '5-2', you must input it as 5 + (-2). Some validation on the expression would be required to ensure each type of operator has the correct the no. of arguments/children, each opening bracket is accompanied by a closing bracket. Also, I should probably mention my friend has already written code which converts the input string into a stack of tokens, if that's going to be helpful for this. I'd appreciate any help at all. Thanks :) (I read that you can write a grammar and use antlr/JavaCC, etc. to create the parse tree, but I'm not familiar with these tools or with writing grammars, so if that's your solution, I'd be grateful if you could provide some helpful tutorials/links for them.)

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  • How to create a Binary Tree from a General Tree?

    - by mno4k
    I have to solve the following constructor for a BinaryTree class in java: BinaryTree(GeneralTree<T> aTree) This method should create a BinaryTree (bt) from a General Tree (gt) as follows: Every Vertex from gt will be represented as a leaf in bt. If gt is a leaf, then bt will be a leaf with the same value as gt If gt is not a leaf, then bt will be constructed as an empty root, a left subTree (lt) and a right subTree (lr). Lt is a stric binary tree created from the oldest subtree of gt (the left-most subtree) and lr is a stric binary tree created from gt without its left-most subtree. The frist part is trivial enough, but the second one is giving me some trouble. I've gotten this far: public BinaryTree(GeneralTree<T> aTree){ if (aTree.isLeaf()){ root= new BinaryNode<T>(aTree.getRootData()); }else{ root= new BinaryNode<T>(null); // empty root LinkedList<GeneralTree<T>> childs = aTree.getChilds(); // Childs of the GT are implemented as a LinkedList of SubTrees child.begin(); //start iteration trough list BinaryTree<T> lt = new BinaryTree<T>(childs.element(0)); // first element = left-most child this.addLeftChild(lt); aTree.DeleteChild(hijos.elemento(0)); BinaryTree<T> lr = new BinaryTree<T>(aTree); this.addRightChild(lr); } } Is this the right way? If not, can you think of a better way to solve this? Thank you!

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  • Saving tree-structures in Databases

    - by Nina Null
    Hello everyone. I use Hibernate/Spring and a MySQL Database for my data management. Currently I display a tree-structure in a JTable. A tree can have several branches, in turn a branch can have several branches (up to nine levels) again, or having leaves. Lately I have performanceproblemes, as soon as I want to create new branches on deeper levels. At this time a branch has a foreign key to its parent. The domainobject has access to its parent by calling getParent(), which returns the parent-branch. The deeper the level, the longer it takes to create a new branch. Microbenchmark results for creating a new branch are like: Level 1: 32 ms. Level 3: 80 ms. Level 9: 232 ms. Obviously the level (which means the number of parents) is responsible for this. So I wanted to ask, if there are any appendages to work around this kind of problem. I don’t understand why Hibernate needs to know about the whole object tree (all parents until the root) while creating a new branch. But as far as I know this can be the only reason for the delay while creating a new branch, because a branch doesn’t have any other relations to any other objects. I would be very thankful for any workarounds or suggestions. greets, jambusa

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  • Permuting a binary tree without the use of lists

    - by Banang
    I need to find an algorithm for generating every possible permutation of a binary tree, and need to do so without using lists (this is because the tree itself carries semantics and restraints that cannot be translated into lists). I've found an algorithm that works for trees with the height of three or less, but whenever I get to greater hights, I loose one set of possible permutations per height added. Each node carries information about its original state, so that one node can determine if all possible permutations have been tried for that node. Also, the node carries information on weather or not it's been 'swapped', i.e. if it has seen all possible permutations of it's subtree. The tree is left-centered, meaning that the right node should always (except in some cases that I don't need to cover for this algorithm) be a leaf node, while the left node is always either a leaf or a branch. The algorithm I'm using at the moment can be described sort of like this: if the left child node has been swapped swap my right node with the left child nodes right node set the left child node as 'unswapped' if the current node is back to its original state swap my right node with the lowest left nodes' right node swap the lowest left nodes two childnodes set my left node as 'unswapped' set my left chilnode to use this as it's original state set this node as swapped return null return this; else if the left child has not been swapped if the result of trying to permute left child is null return the permutation of this node else return the permutation of the left child node if this node has a left node and a right node that are both leaves swap them set this node to be 'swapped' The desired behaviour of the algoritm would be something like this: branch / | branch 3 / | branch 2 / | 0 1 branch / | branch 3 / | branch 2 / | 1 0 <-- first swap branch / | branch 3 / | branch 1 <-- second swap / | 2 0 branch / | branch 3 / | branch 1 / | 0 2 <-- third swap branch / | branch 3 / | branch 0 <-- fourth swap / | 1 2 and so on... Sorry for the ridiculisly long and waddly explanation, would really, really apreciate any sort of help you guys could offer me. Thanks a bunch!

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  • Delete on a very deep tree

    - by Kathoz
    I am building a suffix trie (unfortunately, no time to properly implement a suffix tree) for a 10 character set. The strings I wish to parse are going to be rather long (up to 1M characters). The tree is constructed without any problems, however, I run into some when I try to free the memory after being done with it. In particularly, if I set up my constructor and destructor to be as such (where CNode.child is a pointer to an array of 10 pointers to other CNodes, and count is a simple unsigned int): CNode::CNode(){ count = 0; child = new CNode* [10]; memset(child, 0, sizeof(CNode*) * 10); } CNode::~CNode(){ for (int i=0; i<10; i++) delete child[i]; } I get a stack overflow when trying to delete the root node. I might be wrong, but I am fairly certain that this is due to too many destructor calls (each destructor calls up to 10 other destructors). I know this is suboptimal both space, and time-wise, however, this is supposed to be a quick-and-dirty solution to a the repeated substring problem. tl;dr: how would one go about freeing the memory occupied by a very deep tree? Thank you for your time.

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  • Transform XAML syntax from Shorthand to full syntax

    - by Emad
    Is there a tool or a simple way to transform XAML code from the shorthand syntax to the full syntax? For example: moving from something like: <_TextBox Text="{Binding Path=Formula.Production, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" to <_TextBox <_TextBox.Text <Binding Path="Formula.NumCloses" Mode="TwoWay" UpdateSourceTrigger="PropertyChanged" </Binding </TextBox.Text </TextBox ? Thanks

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  • Better C# Syntax Coloring for Visual Studio 2010?

    - by Oak
    Coming from Eclipse, I'm disappointed with the very limited syntax coloring capabilities offered for C# by Visual Studio (all versions, up to 2010). In particular, I'm interesting in distinct coloring for methods / fields / locals / static stuff. I'm aware Visual Assist can enhance the coloring, but I've failed to find any free alternative capable of doing that, so I'm turning to SO (I hope it's programming-related enough). Is there any free (or at least cheaper than Visual Assist) solution capable of enhancing the syntax coloring for C#?

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  • Problem with list slice syntax in python

    - by Dingle
    The extended indexing syntax is mentioned in python's doc. slice([start], stop[, step]) Slice objects are also generated when extended indexing syntax is used. For example: a[start:stop:step] or a[start:stop, i]. See itertools.islice() for an alternate version that returns an iterator. a[start:stop:step] works as described. But what about the second one? How is it used?

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  • "OR" Operator must be placed at end of previous line? (unexpected tOROP)

    - by akonsu
    I am running Ruby 1.9. This is a valid syntax: items = (data['DELETE'] || data['delete'] || data['GET'] || data['get'] || data['POST'] || data['post']) But this gives me an error: items = (data['DELETE'] || data['delete'] || data['GET'] || data['get'] || data['POST'] || data['post']) t.rb:8: syntax error, unexpected tOROP, expecting ')' || data['GET'] || data['get'] |... ^ Why?!

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  • What is the Microsoft Query Syntax for Subqueries?

    - by Kuyenda
    I am trying to do a simple subquery join in Microsoft Query, but I cannot figure out the syntax. I also cannot find any documentation for the syntax. How would I write the following query in Microsoft Query? SELECT * FROM ( SELECT Col1, Col2 FROM `C:\Book1.xlsx`.`Sheet1$` ) AS a JOIN ( SELECT Col1, Col3 FROM `C:\Book1.xlsx`.`Sheet1$` ) AS b ON a.Col1 = b.Col1 Is there official documentation for Microsoft Query? Thanks!

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  • Java syntax of +

    - by Pindatjuh
    Why is the following syntax correct: x = y+++y; (Where it means y++ + y or y + ++y which both mean y * 2 + 1) But this is not valid syntax: x = y+++++y; (Which should mean y++ + ++y, which must mean y and increase y and then add ++y which increases y thus y * 2 + 2) Is there a reason for this?

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  • How to use vim's syntax files in emacs to color the text

    - by Vijayender
    Are there any snippets to make emacs use the .vim syntax files found in /usr/share/vim/vimfiles/ for coloring text. Many applications like conky have the vim syntax files like "conkyrc.vim" for vim but not for emacs. So is there an easy way to use those files rather than rewriting a new language-mode for each of those available in vimfiles directory.

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  • Should the syntax for disabling code differ from that of normal comments?

    - by deltreme
    For several reasons during development I sometimes comment out code. As I am chaotic and sometimes in a hurry, some of these make it to source control. I also use comments to clarify blocks of code. For instance: MyClass MyFunction() { (...) // return null; // TODO: dummy for now return obj; } Even though it "works" and alot of people do it this way, it annoys me that you cannot automatically distinguish commented-out code from "real" comments that clarify code: it adds noise when trying to read code you cannot search for commented-out code for for instance an on-commit hook in source control. Some languages support multiple single-line comment styles - for instance in PHP you can either use // or # for a single-line comment - and developers can agree on using one of these for commented-out code: # return null; // TODO: dummy for now return obj; Other languages - like C# which I am using today - have one style for single-line comments (right? I wish I was wrong). I have also seen examples of "commenting-out" code using compiler directives, which is great for large blocks of code, but a bit overkill for single lines as two new lines are required for the directive: #if compile_commented_out return null; // TODO: dummy for now #endif return obj; So as commenting-out code happens in every(?) language, shouldn't "disabled code" get its own syntax in language specifications? Are the pro's (separation of comments / disabled code, editors / source control acting on them) good enough and the cons ("shouldn't do commenting-out anyway", not a functional part of a language, potential IDE lag (thanks Thomas)) worth sacrificing? Edit I realise the example I used is silly; the dummy code could easily be removed as it is replaced by the actual code.

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  • Interfaces on an abstract class

    - by insta
    My coworker and I have different opinions on the relationship between base classes and interfaces. I'm of the belief that a class should not implement an interface unless that class can be used when an implementation of the interface is required. In other words, I like to see code like this: interface IFooWorker { void Work(); } abstract class BaseWorker { ... base class behaviors ... public abstract void Work() { } protected string CleanData(string data) { ... } } class DbWorker : BaseWorker, IFooWorker { public void Work() { Repository.AddCleanData(base.CleanData(UI.GetDirtyData())); } } The DbWorker is what gets the IFooWorker interface, because it is an instantiatable implementation of the interface. It completely fulfills the contract. My coworker prefers the nearly identical: interface IFooWorker { void Work(); } abstract class BaseWorker : IFooWorker { ... base class behaviors ... public abstract void Work() { } protected string CleanData(string data) { ... } } class DbWorker : BaseWorker { public void Work() { Repository.AddCleanData(base.CleanData(UI.GetDirtyData())); } } Where the base class gets the interface, and by virtue of this all inheritors of the base class are of that interface as well. This bugs me but I can't come up with concrete reasons why, outside of "the base class cannot stand on its own as an implementation of the interface". What are the pros & cons of his method vs. mine, and why should one be used over another?

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  • using an alternative string quotation syntax in python

    - by Cawas
    Just wondering... I find using escape characters too distracting. I'd rather do something like this: print ^'Let's begin and end with sets of unlikely 2 chars and bingo!'^ Let's begin and end with sets of unlikely 2 chars and bingo! Note the ' inside the string, and how this syntax would have no issue with it, or whatever else inside for basically all cases. Too bad markdown can't properly colorize it (yet), so I decided to <pre> it. Sure, the ^ could be any other char, I'm not sure what would look/work better. That sounds good enough to me, tho. Probably some other language already have a similar solution. And, just maybe, Python already have such a feature and I overlooked it. I hope this is the case. But if it isn't, would it be too hard to, somehow, change Python's interpreter and be able to select an arbitrary (or even standardized) syntax for notating the strings? I realize there are many ways to change statements and the whole syntax in general by using pre-compilators, but this is far more specific. And going any of those routes is what I call "too hard". I'm not really needing to do this so, again, I'm just wondering.

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  • PHP Object Access Syntax Question with the $

    - by ImperialLion
    I've been having trouble searching for this answer because I am not quite sure how to phrase it. I am new to PHP and still getting my feet on the ground. I was writing a page with a class in it that had the property name. When I originally wrote the page there was no class so I just had a variable called $name. When I went to encapsulate it in a class I accidental changed it to be $myClass->$name. It tool me a while to realize that the syntax I needed was $myClass->name. The reason it took so long was the error I kept getting was "Attempt to access a null property" or something along those lines. The error lead me to believe it was a data population error. My question is does $myClass->$name have a valid meaning? In other words is there a time you would use this and a reason why it doesn't create a syntax error? If so what is the semantic meaning of that code? When would I use it if it is valid? If its not valid, is there a reason that it doesn't create a syntax error?

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