Search Results

Search found 12058 results on 483 pages for 'abstract syntax tree'.

Page 22/483 | < Previous Page | 18 19 20 21 22 23 24 25 26 27 28 29  | Next Page >

  • php syntax confusion accessing database result

    - by Babak
    I am trying to do the following: <?php foreach($sqlResult as $row): ?> <tr> <?php foreach($formdata['columns'] as $column): ?> <td><?php echo $row->$column['name']; ?></td> <?php endforeach; ?> </tr> <?php endforeach; ?> This does not work. $row is returned by my mysql query, it has the following : row-id, row-author, row-name and these work as they echo fine. $columns is the following array: 'columns' => array ( 1 => array ( 'name' => 'id' ), 2 => array ( 'name' => 'author' ), 3 => array ( 'name' => 'date' ), 4 => array ( 'name' => 'title' ) it also works fine as $column['name'] echoes id, author, date, title my question is how would it be possible for me to access the $row-method (is it a method?) by passing it a name from the array??

    Read the article

  • New/strange Java "try()" syntax?

    - by Ali
    While messing around with the custom formatting options in Eclipse, in one of the sample pieces of code, I say code as follows: /** * 'try-with-resources' */ class Example { void foo() { try (FileReader reader1 = new FileReader("file1"); FileReader reader2 = new FileReader("file2")) { } } } I've never seen try used like this and I've been coding in Java for 9 years! Does any one know why you would do this? What is a possible use-case / benefit of doing this? An other pieces of code I saw, I thought was a very useful shorthand so I'm sharing it here as well, it's pretty obvious what it does: /** * 'multi-catch' */ class Example { void foo() { try { } catch (IllegalArgumentException | NullPointerException | ClassCastException e) { e.printStackTrace(); } } }

    Read the article

  • Javascript Instance Variable Syntax (AJAX page refresh)

    - by Rosarch
    I'm having difficulty with Javascript instance variables. I'm trying to make an easy way to refresh the chat page, looking for new messages. The AJAX call supplies a mid, or the lowest message id to be returned. This allows the call to only ask for the most recent messages, instead of all of them. MessageRefresher.prototype._latest_mid; function MessageRefresher(latest_mid) { this._latest_mid = latest_mid; // it thinks `this` refers to the MessageRefresher object } MessageRefresher.prototype.refresh = function () { refreshMessages(this._latest_mid); // it thinks `this` refers to the window this._latest_mid++; } function refreshMessages(latest_mid) { $.getJSON('API/read_messages', { room_id: $.getUrlVar('key'), mid: latest_mid }, function (messages) { for (var i = 0; i < messages[0].length; i++) { var newChild = sprintf("<li>%s: %s</li>", messages[1][i], messages[0][i]); $("#messages").append(newChild); } }); var messageRefresher = new MessageRefresher(0); setInterval(messageRefresher.refresh, 1000); This results in all the messages being printed out, over and over again. I know it has other bugs, but the main issue I'm trying to work out right now is the use of the instance variable. Or is there another way I should be going about doing this?

    Read the article

  • Question about Transact SQL syntax

    - by Yousui
    Hi guys, The following code works like a charm: BEGIN TRY BEGIN TRANSACTION COMMIT TRANSACTION END TRY BEGIN CATCH IF @@TRANCOUNT > 0 ROLLBACK; DECLARE @ErrorMessage NVARCHAR(4000), @ErrorSeverity int; SELECT @ErrorMessage = ERROR_MESSAGE(), @ErrorSeverity = ERROR_SEVERITY(); RAISERROR(@ErrorMessage, @ErrorSeverity, 1); END CATCH But this code gives an error: BEGIN TRY BEGIN TRANSACTION COMMIT TRANSACTION END TRY BEGIN CATCH IF @@TRANCOUNT > 0 ROLLBACK; RAISERROR(ERROR_MESSAGE(), ERROR_SEVERITY(), 1); END CATCH Why?

    Read the article

  • better for-loop syntax for detecting empty sequences?

    - by Dmitry Beransky
    Hi, Is there a better way to write the following: row_counter = 0 for item in iterable_sequence: # do stuff with the item counter += 1 if not row_counter: # handle the empty-sequence-case Please keep in mind that I can't use len(iterable_sequence) because 1) not all sequences have known lengths; 2) in some cases calling len() may trigger loading of the sequence's items into memory (as the case would be with sql query results). The reason I ask is that I'm simply curious if there is a way to make above more concise and idiomatic. What I'm looking for is along the lines of: for item in sequence: #process item *else*: #handle the empty sequence case (assuming "else" here worked only on empty sequences, which I know it doesn't)

    Read the article

  • Why was this T-SQL Syntax never implemented?

    - by ChrisA
    Why did they never let us do this sort of thing: Create Proc RunParameterisedSelect @tableName varchar(100), @columnName varchar(100), @value varchar(100) as select * from @tableName where @columnName = @value You can use @value as a parameter, obviously, and you can achieve the whole thing with dynamic SQL, but creating it is invariably a pain. So why didn't they make it part of the language in some way, rather than forcing you to EXEC(@sql)?

    Read the article

  • Unfamiliar Javascript Syntax

    - by user1051643
    Long and short of the story is, whilst reading John Resig's blog (specifically http://ejohn.org/blog/javascript-trie-performance-analysis/) I came across a line which makes absolutely no sense to me whatsoever. Essentially it boils down to object = object[key] = something; (this can be found in the first code block of the article I've linked.) This has proven rather difficult to google, so if anyone can offer some insight / a good online resource for me to learn for myself, I'd much appreciate it.

    Read the article

  • mysql syntax how to add a third table to $query

    - by IberoMedia
    I have code: $query = "SELECT a.*, c.name as categoryname, c.id as categoryid". " FROM #__table_one as a". " LEFT JOIN #__table_two c ON c.id = a.catid"; $query .= " WHERE a.published = 1" ." AND a.access <= {$aid}" ." AND a.trash = 0" ." AND c.published = 1" ." AND c.access <= {$aid}" ." AND c.trash = 0" ; I would like to add a third table ('__some_table') for the parts of the query where a.publish, a.access and a.trash. In other words, I want these fields to be retrieved from another table, not "#__table_one", but I do not know how to incorporate the #__some_table into the current query I imagine the JOIN command can help me, but I do not know how to code mysql Thank you,

    Read the article

  • PHP classes, parse syntax errors when using 'var' to declare variables

    - by jon
    I am a C# guy trying to translate some of my OOP understanding over to php. I'm trying to make my first class object, and are hitting a few hitches. Here is the beginning of the class: <?php require("Database/UserDB.php"); class User { private var $uid; private var $username; private var $password; private var $realname; private var $email; private var $address; private var $phone; private var $projectArray; public function _construct($username) { $userArray = UserDB::GetUserArray($username); $uid = $userArray['uid']; $username = $userArray['username']; $realname = $userArray['realname']; $email = $userArray['email']; $phone = $userArray['phone']; $i = 1; $projectArray = UserDB::GetUserProjects($this->GetID()); while($projectArray[$i] != null) { $projectArray[$i] = new Project($projectArray[$i]); } UserDB.php is where I have all my static functions interacting with the Database for this User Class. I am getting errors using when I use var, and I'm getting confused. I know I don't HAVE to use var, or declare the variables at all, but I feel it is a better practice to do so. the error is "unexpected T_VAR, expecting T_VARIABLE" When I simply remove var from the declarations it works. Why is this?

    Read the article

  • MATLAB syntax of (:)

    - by user198729
    >> I=[2 1 3;3 2 4] I = 2 1 3 3 2 4 >> I(:) ans = 2 3 1 2 3 4 >> I(1:2) ans = 2 3 >> Why the first call I(:) returns a vector while the second I(1:2) doesn't which is essentially the same as I(:)?

    Read the article

  • What's wrong with this Perl 'grep' syntax?

    - by wes
    I've got a data structure that is a hash that contains an array of hashes. I'd like to reach in there and pull out the first hash that matches a value I'm looking for. I tried this: my $result = shift grep {$_->{name} eq 'foo'} @{$hash_ref->{list}}; But that gives me this error: Type of arg 1 to shift must be array (not grep iterator). I've re-read the perldoc for grep and I think what I'm doing makes sense. grep returns a list, right? Is it in the wrong context? I'll use a temporary variable for now, but I'd like to figure out why this doesn't work.

    Read the article

  • .htaccess: RewriteCond syntax?

    - by Rosarch
    I'm using Drupal 6. Typically, when the user requests a URL for which Drupal has no response, it uses index.php as the error document. However, I'd like to suspend this behavior for a specific URL. How can I do this? RewriteCond %{REQUEST_FILENAME} !=fail RewriteCond %{REQUEST_FILENAME} !-f RewriteCond %{REQUEST_FILENAME} !-d RewriteCond %{REQUEST_URI} !=/favicon.ico RewriteRule ^(.*)$ index.php?q=$1 [L,QSA] Where "fail" is the path I want to block. So www.example.com/fail should result in a 404. Incidentally, what does [L, QSA] do? I've looked at documentation without luck.

    Read the article

  • Google App Engine: Difficulty with Users API (or maybe just a Python syntax problem)

    - by Rosarch
    I have a simple GAE app that includes a login/logout link. This app is running on the dev server at the moment. The base page handler gets the current user, and creates a login/logout url appropriately. It then puts this information into a _template_data dictionary, for convenience of subclasses. class BasePage(webapp.RequestHandler): _user = users.get_current_user() _login_logout_link = None if _user: _login_logout_link = users.create_logout_url('/') else: _login_logout_link = users.create_login_url('/') _template_data = {} _template_data['login_logout_link'] = _login_logout_link _template_data['user'] = _user def render(self, templateName, templateData): path = os.path.join(os.path.dirname(__file__), 'Static/Templates/%s.html' % templateName) self.response.out.write(template.render(path, templateData)) Here is one such subclass: class MainPage(BasePage): def get(self): self.render('start', self._template_data) The login/logout link is displayed fine, and going to the correct devserver login/logout page. However, it seems to have no effect - the server still seems to think the user is logged out. What am I doing wrong here?

    Read the article

  • Makefile: couple syntax questions

    - by Michael
    package_version := $(version)x0d$(date) what is the x0d part between version and date vars? is it just string? What $(dotin_files:.in=) does below code dotin_files := $(shell find . -type f -name \*.in) dotin_files := $(dotin_files:.in=) what this means $(dotin_files:=.in) code $(dotin_files): $(dotin_files:=.in) $(substitute) [email protected] > $@ can target contain multiple files? what is the meaning of declaring target variable as PHONY? code .PHONY: $(dotin_files) In the regex replacement code below code substitute := perl -p -e 's/@([^@]+)@/defined $$ENV{$$1} ? $$ENV{$$1} : $$&/ge' what are $$ENV{$$1} and $$&? I guess it's Perl scope... thanks for your time

    Read the article

  • A question about c/c++ syntax

    - by user198729
    I don't have the c++ environment yet right now. It seems to me that a function must be declared/defined first to be called in c. I mean, the declared/defined part should be ahead of the calling part. Is it the same in c++? Finally, it seems c++ is adding new features to itself, what about c, has it stopped being developed?

    Read the article

  • How to avoid general names for abstract classes?

    - by djechlin
    In general it's good to avoid words like "handle" or "process" as part of routine names and class names, unless you are dealing with (e.g.) file handles or (e.g.) unix processes. However abstract classes often don't really know what they're going to do with something besides, say, process it. In my current situation I have an "EmailProcessor" that logs into a user's inbox and processes messages from it. It's not really clear to me how to give this a more precise name, although I've noticed the following style matter arises: better to treat derived classes as clients and named the base class by the part of the functionality it implements? Gives it more meaning but will violate is-a. E.g. EmailAcquirer would be a reasonable name since it's acquiring for the derived class, but the derived class won't be acquiring for anyone. Or just really vague name since who knows what the derived classes will do. However "Processor" is still too general since it's doing many relevant operations, like logging in and using IMAP. Any way out of this dilemma? Problem is more evident for abstract methods, in which you can't really answer the question "what does this do?" because the answer is simply "whatever the client wants."

    Read the article

  • Getting link to abstract indexed in Google Scholar

    - by JordanReiter
    We have a large digital library with thousands of papers indexed in Google Scholar. We allow Google Scholar to index our PDFs but they're blocked unless you have a subscription. So Google has full-text indexing/searching of our PDFs (great!) but then the links point just to those PDFs (boo!) instead of the more helpful abstract pages. Does anyone know what could cause an issue like this? I am, to the best of my knowledge, following all of the guidelines laid out in their Inclusion Guidelines. Here's some example meta data: <meta name="citation_title" content="Sample Title"/> <meta name="citation_author" content="LastName, FirstName"/> <meta name="citation_publication_date" content="2012/06/26"/> <meta name="citation_volume" content="1"/> <meta name="citation_issue" content="1"/> <meta name="citation_firstpage" content="10"/> <meta name="citation_lastpage" content="20"/> <meta name="citation_conference_title" content="Name of the Conference"/> <meta name="citation_isbn" content="1-234567-89-X"/> <meta name="citation_pdf_url" content="http://www.example.org/p/1234/proceeding_1234.pdf"/> <meta name="citation_fulltext_html_url" content="http://www.example.org/f/1234/"/> <meta name="citation_abstract_html_url" content="http://www.example.org/p/1234/"/> <link rel="canonical" href="http://www.example.org/p/1234/" /> example.org/p/1234 is the abstract page for the article; example.org/f/1234 is the fulltext link accessible to subscribers only (and to Google Scholar). example.org/p/1234/proceeding_1234.pdf is the fulltext PDF link.

    Read the article

  • What am I not getting about this abstract class implementation?

    - by Schnapple
    PREFACE: I'm relatively inexperienced in C++ so this very well could be a Day 1 n00b question. I'm working on something whose long term goal is to be portable across multiple operating systems. I have the following files: Utilities.h #include <string> class Utilities { public: Utilities() { }; virtual ~Utilities() { }; virtual std::string ParseString(std::string const& RawString) = 0; }; UtilitiesWin.h (for the Windows class/implementation) #include <string> #include "Utilities.h" class UtilitiesWin : public Utilities { public: UtilitiesWin() { }; virtual ~UtilitiesWin() { }; virtual std::string ParseString(std::string const& RawString); }; UtilitiesWin.cpp #include <string> #include "UtilitiesWin.h" std::string UtilitiesWin::ParseString(std::string const& RawString) { // Magic happens here! // I'll put in a line of code to make it seem valid return ""; } So then elsewhere in my code I have this #include <string> #include "Utilities.h" void SomeProgram::SomeMethod() { Utilities *u = new Utilities(); StringData = u->ParseString(StringData); // StringData defined elsewhere } The compiler (Visual Studio 2008) is dying on the instance declaration c:\somepath\somecode.cpp(3) : error C2259: 'Utilities' : cannot instantiate abstract class due to following members: 'std::string Utilities::ParseString(const std::string &)' : is abstract c:\somepath\utilities.h(9) : see declaration of 'Utilities::ParseString' So in this case what I'm wanting to do is use the abstract class (Utilities) like an interface and have it know to go to the implemented version (UtilitiesWin). Obviously I'm doing something wrong but I'm not sure what. It occurs to me as I'm writing this that there's probably a crucial connection between the UtilitiesWin implementation of the Utilities abstract class that I've missed, but I'm not sure where. I mean, the following works #include <string> #include "UtilitiesWin.h" void SomeProgram::SomeMethod() { Utilities *u = new UtilitiesWin(); StringData = u->ParseString(StringData); // StringData defined elsewhere } but it means I'd have to conditionally go through the different versions later (i.e., UtilitiesMac(), UtilitiesLinux(), etc.) What have I missed here?

    Read the article

  • Can I use an abstract class instead of a private __construct() when creating a singleton in PHP?

    - by Pheter
    When creating a Singleton in PHP, I ensure that it cannot be instantiated by doing the following: class Singleton { private function __construct() {} private function __clone() {} public static function getInstance() {} } However, I realised that defining a class as 'abstract' means that it cannot be instantiated. So is there anything wrong with doing the following instead: abstract class Singleton { public static function getInstance() {} } The second scenario allows me to write fewer lines of code which would be nice. (Not that it actually makes much of a difference.)

    Read the article

< Previous Page | 18 19 20 21 22 23 24 25 26 27 28 29  | Next Page >