how does this work?
in irb:
>> class A
>> b = [1, 2,3]
>> end
=> [1, 2, 3]
Is b an instance variable? class variable? how would I access b from
outside the class? Is it used for meta-programming?
Hi,
Im currently developing a cross-platform C application.
Is there any compiler macro which is defined only during compilation on Windows, so I can #ifdef some Windows specific #includes?
Typical example is selecting between WinSock and Berkeley sockets headers:
#ifdef _WINDOWS
#include <winsock.h>
#else
#include <sys/socket.h>
#include <netinet/in.h>
#include <sys/un.h>
#include <arpa/inet.h>
#include <netdb.h>
#endif
So the thing Im looking for is something like that _WINDOWS macro.
Thanks for any tips.
I'm looking for a solution that will allow my rails app to render a user-friendly maintenance page when there is no Mysql server available to connect to.
Normally a Mysql::Error is thrown from the mysql connection adapter in active_record. Something like:
/!\ FAILSAFE /!\ Wed May 26 11:40:14 -0700 2010
Status: 500 Internal Server Error
Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock'
Is there a low-overhead way to catch this error and render a maintenance page instead?
I'm assuming that since connections are actually made in the active_record mysql adapter the app never makes it to the controller stack before it throws the error, so you can't catch it in a controller.
Any input would be greatly appreciated.
"8,5,,1,4,7,,,,7,,1,9,3,6,,,8,6,3,9,,2,5,4,,,,,3,2,,,7,4,1,1,,4,,6,9,,5,,,,5,,,1,,6,3,,,6,5,,,,7,4,,1,7,6,,,,8,,5,,,7,1,,3,9,"
I'm doing a programming challenge where i need to parse this sequence into my sudoku script.
Need to get the above sequence into 8,5,0,1,4,7,0,0,0,7,0,1,9,3,6,0,0,8.........
I tried re but without success, help is appreciated, thanks.
Hi all,
I am working on an artificial intelligence project which is a logic game and aims two user connecting to the server on the network who acts as an Admin and then start to play one by one.
In order to create connections, i have a server code which is just listening on localhost:8000 and assigning team values to the clients as they arrive. After connecting, clients make their move under Admin's control.
The question is that when i try to put my code to work in the browser it fails with the following error:
java.security.AccessControlException: access denied (java.net.SocketPermission 127.0.0.1:8000 connect,resolve)
Even though i have created my own policy, first granting only Socket access permission to the codebase of my project folder (file:///home/xxx/projects/-), after it didnt work i granted all permissions from all codebase. I tried placing my policy file both in the home directory and in the same directory where my applet code resides.
Appreciate any tips, thanks.
Hello,
I know it's not really a programming question but I don't know where to ask it.
Should i use a captcha in my sign up form ?
Facebook, twitter, foursquare, gowalla etc... don't use one (or not a visible one). Is there an invisible catpcha on theses sites ?
Thank you
Hello everyone,
I'm using the rails-settings gem, and I'm trying to understand how you add functions to ActiveRecord classes (I'm building my own library for card games), and I noticed that this gem uses one of the Meta-programming techniques to add the function to the ActiveRecord::Base class (I'm far from Meta-programming master in ruby, but I'm trying to learn it)
module RailsSettings
class Railtie < Rails::Railtie
initializer 'rails_settings.initialize', :after => :after_initialize do
Railtie.extend_active_record
end
end
class Railtie
def self.extend_active_record
ActiveRecord::Base.class_eval do
def self.has_settings
class_eval do
def settings
RailsSettings::ScopedSettings.for_thing(self)
end
scope :with_settings, :joins => "JOIN settings ON (settings.thing_id = #{self.table_name}.#{self.primary_key} AND
settings.thing_type = '#{self.base_class.name}')",
:select => "DISTINCT #{self.table_name}.*"
scope :with_settings_for, lambda { |var| { :joins => "JOIN settings ON (settings.thing_id = #{self.table_name}.#{self.primary_key} AND
settings.thing_type = '#{self.base_class.name}') AND
settings.var = '#{var}'" } }
scope :without_settings, :joins => "LEFT JOIN settings ON (settings.thing_id = #{self.table_name}.#{self.primary_key} AND
settings.thing_type = '#{self.base_class.name}')",
:conditions => 'settings.id IS NULL'
scope :without_settings_for, lambda { |var| { :joins => "LEFT JOIN settings ON (settings.thing_id = #{self.table_name}.#{self.primary_key} AND
settings.thing_type = '#{self.base_class.name}') AND
settings.var = '#{var}'",
:conditions => 'settings.id IS NULL' } }
end
end
end
end
end
end
What I don't understand is why he uses class_eval on ActiveRecord::Base, wasn't it easier if he just open the ActiveRecord::Base class and define the functions? Specially that there's nothing dynamic in the block (What I mean by dynamic is when you do class_eval or instance_eval on a string containing variables)
something like this:
module ActiveRecord
class Base
def self.has_settings
class_eval do
def settings
RailsSettings::ScopedSettings.for_thing(self)
end
scope :with_settings, :joins => "JOIN settings ON (settings.thing_id = #{self.table_name}.#{self.primary_key} AND
settings.thing_type = '#{self.base_class.name}')",
:select => "DISTINCT #{self.table_name}.*"
scope :with_settings_for, lambda { |var| { :joins => "JOIN settings ON (settings.thing_id = #{self.table_name}.#{self.primary_key} AND
settings.thing_type = '#{self.base_class.name}') AND
settings.var = '#{var}'" } }
scope :without_settings, :joins => "LEFT JOIN settings ON (settings.thing_id = #{self.table_name}.#{self.primary_key} AND
settings.thing_type = '#{self.base_class.name}')",
:conditions => 'settings.id IS NULL'
scope :without_settings_for, lambda { |var| { :joins => "LEFT JOIN settings ON (settings.thing_id = #{self.table_name}.#{self.primary_key} AND
settings.thing_type = '#{self.base_class.name}') AND
settings.var = '#{var}'",
:conditions => 'settings.id IS NULL' } }
end
end
end
end
I understand the second class_eval (before the def settings) is to define functions on the fly on every class that 'has_settings' right ? Same question here, I think he could use "def self.settings" instead of "class_eval.... def settings", no ?
Hi, I am learning the Opengl graphic programming at Eclipse. Can someone tell me the difference between GLUT application and SDL application, so that I can dig into either one of them? Tks.
We are programming a new web application framework (Second WAF). I was wondering if we should support cookieless sessions or not.
Who use it and who needs it?
hello I'm new to PHP programming and I migrated from ASP .net to PHP..
I have a div just like below
<div id="mydiv"></div>
what I wanted to do is just to change the text and html content(like some name or any data in it) in it.
What I imagine is just like
mydiv=innertext="some value";
Thanks,
GURU
I'm trying to find out what a binormal is in the context of graphics programming but coming up short, I saw on a site that the binormal was being calculated as the corss between the normal and tangent (i.e. cross(normal, tangent)), is this the correct way to calculate a binormal?
If i have a web application and i receive credit card data transmitted via a POST request by a web browser over HTTPS and instantly open a socket (SSL) to a remote PCI compilant card processor to forward the data and wait for a response, am i allowed to do that? or is this receiving the data with my application and forwarding it already subject of "processing credit card data"?
if i create an iframe that is displayed in a client browser to enter cc data and this iframe posts the data via HTTPS to remote card processor (directly!) is this already a case of processing credit card data? even if my application code 'doesnt touch' the entered data with any event handlers?
i'm interested in the definition "credit card data processing". when does it start to be a cc data processing application? can somebody maybe point me to that section in PCI-DSS standard that clearly defines when you start to 'be a processing application'?
Thanks,
For those of you who are into programming not just for the money. I would like to know which benefits you would like to have (or already have).
OK, maybe taking away the money factor will limit this question too much. I am surprised to see that most companies have a fixed set for their benefits package. Were you able to negotiate something new or just your salary? What things have you seen out there and/or value most?
Is this considered good programming practise in C++:
try {
// some code
}
catch(someException) {
// do something
}
catch (...)
{
// left empty <-- Good Practise???
}
ive a sever running TIdTCPServer, and Client Using Web Browser (or any other software) to Communicate, i dunno the protocol, but what im trying to do is to Send The Data between the client and another Connection (Both Connected to the same TIdTCPServer) for example the data sent by the first client is transmitted to the second client, and the data sent by the second client is transmitted to the first client, like a proxy (i cant really use a proxy server since its just this one condition) and the TIdTCPServer should still be receiving other clients and processing their data.
i stumbled upon the first line of code, since TIdContext.Connection.Socket.ReadLn requires a Delimiter, and the Client's Protocol is unknown to the server.
any ideas?
thanks.
A friend of mine, who studies game development at an university, is currently learning programming in OpenCL. What would be a simple project that teaches the most important aspects of OpenCL and can be finished within about 50 - 100 hours?
Hi there
I'm programming against a Webservice that requires the amount of ticks (for the current time) (A single tick represents one hundred nanoseconds or one ten-millionth of a second) since 1.1.0001 (midnight).
what is the easiest way to get the amount of ticks from an NSDate Object?
thanks for your help
I recently watched a youtube video where a guy got a camera to recognize when a rubik's cube was held up to it, and it captured the 9 square color combination before snapping a picture of the cube and displaying the 3x3 grid on the screen of his computer. What kind of programming is this and where would I start reading to get into this sort of thing? specifically, controlling a camera, and getting it to pick out certain parts of an image and translate that data.
I've been teaching myself object oriented programming and I'm thinking about a situation where I have an object "Transaction", that has quite a few properties to it like account, amount, date, currency, type, etc.
I never plan to mutate these data points, and calculation logic will live in other classes. My question is, is it poor Python design to instantiate thousands of objects just to hold data? I find the data far easier to work with embedded in a class rather than trying to cram it into some combination of data structures.
Whatever it be, caffeine, tobacco, whatever, list your programming performance enhancing drug of choice.
Do you feel like you NEED it to be most effective at your work?
Vote up someone if they answered the same as you.
hello
i never worked with web programming and
i've been asked lately to write a web-based software to manage assets and tasks. to be used by more than 900 persons
what are the recommended modules , frameworks , libraries for this task.
and it will be highly appreciated if you guyz recommend some books and articles that might help me. thanks in advance
This isn't a question about code, but it's programming related. We have a web app that's ready for beta testing. Has anyone noticed any difference between open beta vs. closed beta in terms of the quality or quantity of feedback the testers give or any other factors?
Boost.Asio documentation suggests the following exception handling pattern:
boost::asio::io_service io_service;
...
for (;;)
{
try
{
io_service.run();
break; // run() exited normally
}
catch (my_exception& e)
{
// Deal with exception as appropriate.
}
}
The problem with it is that the context of exception is lost at the point when it's handled. For example, if I have multiple socket sessions going on, I don't know which one caused the exception to be thrown.
What would be a better way to handle the exceptions from asynchronous handlers without wrapping them in try/catch blocks?
I am following the BigNerdRanch iOS Programming book and I am on this one chapter that deals with UITableViewController. I have been wondering however where UITableViewController finds out about its delegate and dataSource. Currently I have it as
@interface ItemsViewController : UITableViewController <UITableViewDataSource, UITableViewDelegate>
But there is nothing that looks like:
[self.tableView setDelegate:self]
I am just wondering how the UITableViewController finds out about its delegate and dataSource
Hello,
I'm new to PHP programming and I wanted to know that is it possible to handle PHP events as we do in ASP.NET
I mean I've got a img and I want to perform some task on click event of this img.
I know how to do it in ASP.NET but please help me in context of PHP
Thanks,
GURU