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?
Not sure how many people out there work with bar codes in their applications. I have been on a few projects that required bar codes to be programatically generated. Having seen this new Tag technology from Microsoft I am wondering if anyone has worked with MS Tag yet? Do you have some examples of programming against MS Tag?
Hello everybody!
I've been wondering whether is possible or not to pass a function as parameter in PHP; I want something like when you're programming in JS:
object.exampleMethod(function(){
// some stuff to execute
});
What I want is to execute that function somewhere in exampleMethod. Is that possible in PHP?
Thank you so much.
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 ?
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?
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.
"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.
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?
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?
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
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
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.
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 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
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.
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?
Is this considered good programming practise in C++:
try {
// some code
}
catch(someException) {
// do something
}
catch (...)
{
// left empty <-- Good Practise???
}
In window programming, what is the difference between solicit and unsolicit message or events. I have seen some saying like we have handled solic or unsolic messages. What is that actually?
Can someone pls help on this?
Hi,
Is it possible to do Aspect Oriented Programming in Delphi? I would be interested in native support as well as third party solutions.
I don't have a specific problem I want to solve with AOP, but am simply interested in studying AOP.
Thanks, Miel Bronneberg.
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
I am newbie to iPhone programming. I am not using Interface Builder in my programming. I have some doubt about memory management, @property topics in iPhone.
Consider the following code
@interface LoadFlag : UIViewController {
UIImage *flag;
UIImageView *preview;
}
@property (nonatomic, retain) UIImageView *preview;
@property (nonatomic, retain) UIImage *flag;
@implementation
@synthesize preview;
@synthesize flag;
- (void)viewDidLoad
{
flag = [UIImage imageNamed:@"myImage.png"]];
NSLog(@"Preview: %d\n",[preview retainCount]); //Count: 0 but shouldn't it be 1 as I am retaining it in @property in interface file
preview=[[UIImageView alloc]init];
NSLog(@"Count: %d\n",[preview retainCount]); //Count: 1
preview.frame=CGRectMake(0.0f, 0.0f, 100.0f, 100.0f);
preview.image = flag;
[self.view addSubview:preview];
NSLog(@"Count: %d\n",[preview retainCount]); //Count: 2
[preview release];
NSLog(@"Count: %d\n",[preview retainCount]); //Count: 1
}
When & Why(what is the need) do I have to set @property with retain (in above case for UIImage & UIImageView) ? I saw this statement in many sample programs but didn't understood the need of it.
When I declare @property (nonatomic, retain) UIImageView *preview; statement the retain Count is 0. Why doesn't it increase by 1 inspite of retaining it in @property.
Also when I declare [self.view addSubview:preview]; then retain Count increments by 1 again. In this case does the "Autorelease pool" releases for us later or we have to take care of releasing it. I am not sure but I think that the Autorelease should handle it as we didn't explicitly retained it so why should we worry of releasing it.
Now, after the [preview release]; statement my count is 1. Now I don't need UIImageView anymore in my program so when and where should I release it so that the count becomes 0 and the memory gets deallocated. Again, I am not sure but I think that the Autorelease should handle it as we didn't explicitly retained it so why should we worry of releasing it. What will happen if I release it in -(void) dealloc method
In the statement - flag = [UIImage imageNamed:@"myImage.png"]]; I haven't allocated any memory to flag but how can I still use it in my program. In this case if I do not allocate memory then who allocates & deallocates memory to it or is the "flag" just a reference pointing to - [UIImage imageNamed:@"myImage.png"]];. If it is a reference only then do i need to release it.
Thanks in advance.
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.
I need to programatically encrypt a directory of files, like in a .zip or whatever. Preferably password protected obviously.
How can I accomplish this, and WHAT IS the BEST encryption way to do it, if applicable?
Programming language doesn't matter. I am dictioned in all syntax.
I'm looking for web app frameworks and/or database administration tools, either popular and unpopular, written in any language, for any relational database.
In short, I'm looking for web accessible CRUD front-ends with minimal programming effort.
For example:
phpMyAdmin (MySQL administration tool)
Ruby on Rails (web app framework with scaffolding)