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  • Best Practice - Validating Input In Simple GUI Application?

    - by Alex
    I'm writing a GUI app with wxwidgets in C++ for one of my programming classes. We have to validate input and throw custom exceptions if it doesn't meet certain conditions. My question is, what is best practice when it comes to this? Should I write a seperate function that checks for errors, and have my event handler's call that function? Or should I do my error-checking in my event handlers? Or does it really matter? Thanks!

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  • Subversion terminology. Difference between projects, modules and root directories

    - by aioobe
    I'm setting up a repository for me and some colleagues. I have a subversion repository at hand, and all required rights. The usual directory-skeleton has been set up for me (branches, tags and trunk). Now I'm about to create a directory for me and my colleagues to put our files in. I'm quite sure the right place to put it is in trunk. Now here and there in tutorials, I see terms like "modules" and "projects" such as in Checking Out a Project - svn checkout svn checkout http://host_name/svn_dir/repository_name/project/trunk proj Is proj in the above line some glorified directory in trunk? Should I do something else than a checkout on trunk, mkdir and then commit when creating a directory for me and my colleagues? Whats the difference between a project, a directory in trunk and a module?

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  • Which programming langauge is the funniest?

    - by Shervin
    I know there are tons of different programming languages, and some of them are made with a tad of sense of humor. But which one is the funniest in your opinion? I have heard of something called Moo (although I am not sure of the exact name), which was a programming language for the JVM. The basic idea was that the only syntax allowed was a fork of Moo, like this: moo; //Means something mooo; //means another thing moooooo; //means something else and so on. That is pretty funny IMO. Not so useful, and definitely not easy to learn, but quite funny.

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  • PDF writeHTML for rendering tables

    - by sami
    I'm using TCPDF and following this example which uses writeHTML and heredoc syntax to write a table. http://www.tcpdf.org/examples/example_048.phps I'm trying to do though is switch the font using setFont before writing each column. This means I have to break the html and write it on different pieces (see pseudo code). But once I break the HTML like that, it doesn't work, I think because it becomes invalid. writeHTML <tr> writeHTML first column setFont() writeHTML second column writeHTML </tr> I want to use writeHTML because it helps me write the table without having to manually construct. But how can I make modifications before I output each cell?

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  • Understanding pattern matching with cons operator

    - by Mathias
    In "Programming F#" I came across a pattern-matching like this one (I simplified a bit): let rec len list = match list with | [] -> 0 | [_] -> 1 | head :: tail -> 1 + len tail;; Practically, I understand that the last match recognizes the head and tail of the list. Conceptually, I don't get why it works. As far as I understand, :: is the cons operator, which appends a value in head position of a list, but it doesn't look to me like it is being used as an operator here. Should I understand this as a "special syntax" for lists, where :: is interpreted as an operator or a "match pattern" depending on context? Or can the same idea be extended for types other than lists, with other operators?

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  • Android HelloWorld Build Path error

    - by BahaiResearch.com
    On my Mac I installed Eclipse, the SDK and created a new project, then hit build expecting to see my first helloworld app. I got the error "the project cannot be built until build path errors are fixed". After going thru all the path-like options in Preferences, I noticed that on the tab "Java Build Path" the "Google APIs [Android 2.2]" option did not have its check box checked. Checking it made the problem go away. It works now and I can see the app in the Emulator Have I not set up my environment correctly? I used all the defaults in Eclipse and the Android SDK.

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  • Python: does it make sense to refactor this check into it's own method?

    - by Jeff Fry
    I'm still learning python. I just wrote this method to determine if a player has won a game of tic-tac-toe yet, given a board state like:'[['o','x','x'],['x','o','-'],['x','o','o']]' def hasWon(board): players = ['x', 'o'] for player in players: for row in board: if row.count(player) == 3: return player top, mid, low = board for i in range(3): if [ top[i],mid[i],low[i] ].count(player) == 3: return player if [top[0],mid[1],low[2]].count(player) == 3: return player if [top[2],mid[1],low[0]].count(player) == 3: return player return None It occurred to me that I check lists of 3 chars several times and could refactor the checking to its own method like so: def check(list, player): if list.count(player) == 3: return player ...but then realized that all that really does is change lines like: if [ top[i],mid[i],low[i] ].count(player) == 3: return player to: if check( [top[i],mid[i],low[i]], player ): return player ...which frankly doesn't seem like much of an improvement. Do you see a better way to refactor this? Or in general a more Pythonic option? I'd love to hear it!

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  • warning in Eclipse

    - by lego69
    hello, I have some problems with Eclipse, I have structure struct Account{ const char* strLastName; //Client's last name const char* strFirstName; //Client's first name int nID; //Client's ID number int nLines; //Number of lines related to account double lastBill; //Client's last bill for all lines List linesDataBase; }; And I can't compile my code eclipse gives me an errors: Syntax error before List no semicolon at end of struct or union ISO does not allow extra ";" outside a function I have no idea how to change it, thanks in advance for any help

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  • MS-Access nested DIR - check if a file exists elsewhere whilst looping through a folder

    - by David Carle
    I have used the DIR() command in Microsoft Access 2003 to loop through the files in folder A. This works fine, but I need to check if each file also exists in another location (folder B), and only process the file if it doesn't exist in folder B. The problem is that checking for the file existing in folder B also uses the DIR() function and this then resets or confuses the original one, with the result that no further files are found in folder A. Is there a way to check if a file exists without using DIR? Or, is there a way to have a separate instance of DIR? I suppose I could build a list of the files in folder A into an array and then process the entries in the array, but this seems rather 'clunky' Any suggestions for a better solution? Thanks

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  • Code editor with autocomplete

    - by Andrey
    I need to create a code editor for my own simple language: className.MethodName(parameterName = 2, ... ) I've created the appropriate grammar and autogenerate parser using ANTLR tool. Now I would like to have an autocomplete for class, method, variables and parameter names. This list should be context dependent, f.e. for "class." it should display methods and for "class.Method(" - parameters. I was going to parse the text and display the list depending on in which node the cursor is. The problem is that for incomplete code like "aaa.bbb(" the parser produces an error instead of a syntax tree. Any idea how to solve this problem? Maybe I'm on the wrong way and I shouldn't parse code to display autocomplete?

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  • How to set document.domain for a dynamically generated IFRAME?

    - by Paras Chopra
    I am implementing CodeMirror (http://marijn.haverbeke.nl/codemirror/) on a page where document.domain needs to be declared (because of other IFRAMES on the page). CodeMirror generates a dynamic IFRAME to provide syntax highlighted code editing. The problem is that IE throws up 'Access Denied' (other browsers are fine) at the following piece of code mirror code: this.win = frame.contentWindow; ... var doc = this.win.document; <-- ERROR doc.open(); doc.write(html.join("")); doc.close(); It turns out IE doesn't inherit document.domain from parent IE. I can set document.domain in the IFRAME contents but IE throws up the error before I can even set the contents. Any ideas how to tackle this problem?

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  • MySQL Export with Column Heading

    - by st4nt0n
    Hello - I am very, very, new to mySQL. I've got experience in general technical terms, but not with the syntax or concepts of mySQL. I have been tasked with exporting a table from MySQL into a pipe delimited .txt or .xls that I can use to add 7500 more records to manually, then import back into the table. I tried to use INTO OUTFILE, but I don't get column headings, which I need for reference to merge the new records. Is there a good resource that can explain this to a complete novice? I would usually go down to my bookstore and start learning, but I'm on a bit of a time crunch. Thanks all!

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  • trigger onchange event manually

    - by Anitha
    Hi all, I'm setting a date-time textfield value via a calendar widget. Obviously, the calendar widget does something like this : document.getElementById('datetimetext').value = date_value; What I want is : On changing value in the date-time textfield I need to reset some other fields in the page. I've added a onchange event listener to the datetimetext field which is not getting triggered, because I guess onchange gets triggered only when the element gets focus & its value is changed on losing focus. Hence I'm looking for a way to manually trigger this onchange event (which I guess should take care of checking the value difference in the text field). Any ideas ? Thanks in advance, Anitha

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  • Dynamic scoping in Clojure?

    - by j-g-faustus
    Hi, I'm looking for an idiomatic way to get dynamically scoped variables in Clojure (or a similar effect) for use in templates and such. Here is an example problem using a lookup table to translate tag attributes from some non-HTML format to HTML, where the table needs access to a set of variables supplied from elsewhere: (def *attr-table* ; Key: [attr-key tag-name] or [boolean-function] ; Value: [attr-key attr-value] (empty array to ignore) ; Context: Variables "tagname", "akey", "aval" '( ; translate :LINK attribute in <a> to :href [:LINK "a"] [:href aval] ; translate :LINK attribute in <img> to :src [:LINK "img"] [:src aval] ; throw exception if :LINK attribute in any other tag [:LINK] (throw (RuntimeException. (str "No match for " tagname))) ; ... more rules ; ignore string keys, used for internal bookkeeping [(string? akey)] [] )) ; ignore I want to be able to evaluate the rules (left hand side) as well as the result (right hand side), and need some way to put the variables in scope at the location where the table is evaluated. I also want to keep the lookup and evaluation logic independent of any particular table or set of variables. I suppose there are similar issues involved in templates (for example for dynamic HTML), where you don't want to rewrite the template processing logic every time someone puts a new variable in a template. Here is one approach using global variables and bindings. I have included some logic for the table lookup: ;; Generic code, works with any table on the same format. (defn rule-match? [rule-val test-val] "true if a single rule matches a single argument value" (cond (not (coll? rule-val)) (= rule-val test-val) ; plain value (list? rule-val) (eval rule-val) ; function call :else false )) (defn rule-lookup [test-val rule-table] "looks up rule match for test-val. Returns result or nil." (loop [rules (partition 2 rule-table)] (when-not (empty? rules) (let [[select result] (first rules)] (if (every? #(boolean %) (map rule-match? select test-val)) (eval result) ; evaluate and return result (recur (rest rules)) ))))) ;; Code specific to *attr-table* (def tagname) ; need these globals for the binding in html-attr (def akey) (def aval) (defn html-attr [tagname h-attr] "converts to html attributes" (apply hash-map (flatten (map (fn [[k v :as kv]] (binding [tagname tagname akey k aval v] (or (rule-lookup [k tagname] *attr-table*) kv))) h-attr )))) (defn test-attr [] "test conversion" (prn "a" (html-attr "a" {:LINK "www.google.com" "internal" 42 :title "A link" })) (prn "img" (html-attr "img" {:LINK "logo.png" }))) user=> (test-attr) "a" {:href "www.google.com", :title "A link"} "img" {:src "logo.png"} This is nice in that the lookup logic is independent of the table, so it can be reused with other tables and different variables. (Plus of course that the general table approach is about a quarter of the size of the code I had when I did the translations "by hand" in a giant cond.) It is not so nice in that I need to declare every variable as a global for the binding to work. Here is another approach using a "semi-macro", a function with a syntax-quoted return value, that doesn't need globals: (defn attr-table [tagname akey aval] `( [:LINK "a"] [:href ~aval] [:LINK "img"] [:src ~aval] [:LINK] (throw (RuntimeException. (str "No match for " tagname))) ; ... more rules [(string? ~akey)] [] ))) Only a couple of changes are needed to the rest of the code: In rule-match?, when syntax-quoted the function call is no longer a list: - (list? rule-val) (eval rule-val) + (seq? rule-val) (eval rule-val) In html-attr: - (binding [tagname tagname akey k aval v] - (or (rule-lookup [k tagname] *attr-table*) kv))) + (or (rule-lookup [k tagname] (attr-table tagname k v)) kv))) And we get the same result without globals. (And without dynamic scoping.) Are there other alternatives to pass along sets of variable bindings declared elsewhere, without the globals required by Clojure's binding? Is there an idiomatic way of doing it, like Ruby's binding or Javascript's function.apply(context)?

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  • Setting properties of auto-generated listboxitem

    - by DerKlaus
    I am trying to set the inputbindings of the auto-generated ListBoxItems of a databound ListBox. The code below does not work. The compiler complains that "The Property Setter 'InputBindings' cannot be set because it does not have an accessible set accessor." What is the correct syntax to set the InputBindings? <ListBox.ItemContainerStyle> <Style TargetType="{x:Type ListBoxItem}"> <Setter Property="ListBoxItem.InputBindings"> <Setter.Value> <MouseBinding Command="{Binding OpenCommand}" Gesture="LeftDoubleClick"/> </Setter.Value> </Setter> </Style> </ListBox.ItemContainerStyle> PS: Posting does not work with Opera 10.51

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  • Getting "Illegal Seek" error after calling accept()

    - by Bilthon
    Well.. it's pretty much that, I seem to be getting a "Illegal Seek" error when checking my errno variable. The problem is that I have no idea of what that can mean. I know sockets are treated like files in unix, but I can't see how can this be related to sockets. What I'm doing exactly is: int sck = ::accept(m_socket, (struct sockaddr*)&client_address, (socklen_t*)&address_len); Then I get sck = -1 and errno = ESPIPE And the weird thing is that it happens randomly. I mean, sometimes the code works fine, and sometimes it just thows an exception. I'm working with threads so that's understandable. But I just would like to know what kind of behaviour makes the accept() call to set errno as ESPIPE so I could check the paramethers for instance. Thanks Nelson R. Pérez

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  • Reliable way to get the "ancestor" of an object with a specific classname, using jQuery

    - by Matt Dawdy
    I've got a javascript function that gets called on change event of a select form element. So, the "this" variable in js refers to the select element. This select element is in a td tag, in a tr tag. The tr tag has a classname of "FilterDetailsRow". Now, I've tested, and if I use this syntax: var filterRow = $(this).parent().parent(); it gets me what I want. However, is there a better way to tell jQuery, "starting with "this" can you please go up my tree of parents until you find one with a classname of "FilterDetailsRow"? Here's what I came up with, but I want to make sure I"m not reinventing the wheel. function GetFilterDetailsRowOfObject(o) { if (o) { if (o.parent()[0].className.indexOf("FilterDetailsRow") != -1) return o; else return GetFilterDetailsRowOfObject(o.parent()); } else { return null; } } Thanks for any advice.

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  • How does memory management in Java and C# differ?

    - by David Johnstone
    I was reading through 2010 CWE/SANS Top 25 Most Dangerous Programming Errors and one of the entries is for Buffer Copy without Checking Size of Input. It suggests using a language with features to prevent or mitigate this problem, and says: For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer. I was not aware that Java and C# differed in any meaningful way with regard to memory management. How is it that Java is not subject to buffer overflows, while C# only protects against overflows? And how is it possible to disable this protection in C#?

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  • Typescript + requirejs: How to handle circular dependencies?

    - by Aymeric Gaurat-Apelli
    I am in the process of porting my JS+requirejs code to typescript+requirejs. One scenario I haven't found how to handle is circular dependencies. Require.js returns undefined on modules that are also dependent on the current and to solve this problem you can do: MyClass.js define(["Modules/dataModel"], function(dataModel){ return function(){ dataModel = require("Modules/dataModel"); ... } }); Now in typescript, I have: MyClass.ts import dataModel = require("Modules/dataModel"); class MyClass { dataModel: any; constructor(){ this.dataModel = require("Modules/dataModel"); // <- this kind of works but I lose typechecking ... } } How to call require a second time and yet keep the type checking benefits of typescript? dataModel is a module { ... }

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  • Make A HTML/PHP Link

    - by Will Evans
    I have the code below: $result = mysql_query("SELECT link, notes FROM links WHERE username='will';"); $html .= "<ul>"; while ($row = mysql_fetch_array($result)) { //loop extract($row); $html .= "<li>{$link} - {$notes}</li>"; } I need the bit where it says {$link} to become a clickable link which opens a new window. How would I do this? When I put tags around it you get this error: The error is: Parse error: syntax error, unexpected '{' in /data/www/vhosts/themacsplash.com/httpdocs/ClipBoy/will.php on line 18 Line 18 is $html .= "{$link} - {$notes}";

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  • MySQL: updating a row and deleting the original in case it becomes a duplicate

    - by Silvio Donnini
    I have a simple table made up of two columns: col_A and col_B. The primary key is defined over both. I need to update some rows and assign to col_A values that may generate duplicates, for example: UPDATE `table` SET `col_A` = 66 WHERE `col_B` = 70 This statement sometimes yields a duplicate key error. I don't want to simply ignore the error with UPDATE IGNORE, because then the rows that generate the error would remain unchanged. Instead, I want them to be deleted when they would conflict with another row after they have been updated I'd like to write something like: UPDATE `table` SET `col_A` = 66 WHERE `col_B` = 70 ON DUPLICATE KEY REPLACE which unfortunately isn't legal in SQL, so I need help finding another way around. Also, I'm using PHP and could consider a hybrid solution (i.e. part query part php code), but keep in mind that I have to perform this updating operation many millions of times. thanks for your attention, Silvio Reminder: UPDATE's syntax has problems with joins with the same table that is being updated

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  • How do I use a variable argument number in a bash script?

    - by Corbin Tarrant
    #!/bin/bash # Script to output the total size of requested filetype recursively # Error out if no file types were provided if [ $# -lt 1 ] then echo "Syntax Error, Please provide at least one type, ex: sizeofTypes {filetype1} {filetype2}" exit 0 fi #set first filetype types="-name *."$1 #loop through additional filetypes and append num=1 while [ $num -lt $# ] do (( num++ )) types=$types' -o -name *.'$$num done echo "TYPES="$types find . -name '*.'$1 | xargs du -ch *.$1 | grep total The problem I'm having is right here: #loop through additional filetypes and append num=1 while [ $num -lt $# ] do (( num++ )) types=$types' -o -name *.'>>$$num<< done I simply want to iterate over all the arguments not including the first one, should be easy enough, but I'm having a difficult time figuring out how to make this work

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  • is there any way to group css styles based on their ids?

    - by Brian
    If I have a chunk of css styles that are applied within a certain page element, I would like to group them rather than identify the containing page element for each style. For example, I would like to turn: #bodywrap #leftcolumn p {...} #bodywrap #leftcolumn div {...} #bodywrap #leftcolumn .highlight {...} into something like: #bodywrap #leftcolumn [ p {...} div {...} .highlight {...} ] where everything contained in the brackets respects the containing declarations. Is this possible with css, and what would be the syntax?

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  • How do you use vim's quickfix feature?

    - by hora
    I'm a pretty new Vim user and I've found that its learning curve is quite steep (at least for me). I just installed this vim script for JavaScriptLint error checking, which shows errors in vim's quickfix window once I save a buffer. However, I don't know what to do next.. How do I 'scroll' through all the errors? How do I close the quickfix 'window'? How do I get it to check for errors after I've made changes to my code? I've looked at the vim quickfix docs but the amount of commands are overwhelming and I can't seem to find what I want. Any help would be appreciated. A side question: is there any way to have javascriptlint check for js errors for code residing in a .html file? Thanks!

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  • How to check if a variable exists in a FreeMarker template?

    - by Don
    Hi, I have a Freemarker template which contains a bunch of placeholders for which values are supplied when the template is processed. I want to conditionally include part of the template if the userName variable is supplied, something like: [#if_exists userName] Hi ${userName}, How are you? [/#if_exists] However, the FreeMarker manual seems to indicate that if_exists is deprecated, but I can't find another way to achieve this. Of course, I could simple providing an additional boolean variable isUserName and use that like this: [#if isUserName] Hi ${userName}, How are you? [/#if] But if there's a way of checking whether userName exists then I can avoid adding this extra variable. Cheers, Don

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