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  • When did the idea of macros (user-defined code transformation) appear?

    - by Jay
    I have read McCarthy's 1960 paper on LISP and found no reference to anything that's similar to user-defined macros or normal order evaluation. I was wondering when marcos first appeared in programming language history (and also in Lisp history): When was the idea of user-defined code transformation (before interpretation or compilation) first described (theoretically)? What was the first programming language implementation to have Lisp-like macros (by "Lisp-like" I mean "using a readable Turing-complete language to do code-transformation")? (including non-Lisps -- Forth for example is quite old, but I'm not sure if the first Forth implementation already had "IMMEDIATE") What was the first Lisp dialect to have macros? Thank you!

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  • Freeglut ( OpenGL ) in C

    - by user1832149
    I would like to ask for you a little help in my homework. I'm learning at an university of Debrecen, and I would like to be a programmer, but I'm stuck with this homework. It's a OpenGL project in C. (freeglut) The next task is about: Window to viewport transformation. Draw graphs of functions, as shown below. The individual views (viewport) defines four different rectangles. Functions look like this picture: one window in 4 piece, and one pice of one function. The functions, respectively: f(x)=x2 g(x)=x3 h(x)=sin(x) i(x)=cos(x) Heres a pic what I need to make: How would I approach such a task?

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  • Check boxes for a has_many and belongs_to association.

    - by Thomas
    I have a has_many and belongs_to association. class Link < ActiveRecord::Base has_and_belongs_to_many :categories belongs_to :property end class Property < ActiveRecord::Base has_many :links end In the index and show I have <%= link.property.name %> and it will show the Property that I assigned to the link with the console just fine. I have a problem with figuring out how to show check boxes in the _form that assign a property to the link (a drop down would work as well). It seems everyone who has had this question before has ether a has_many :through or a HABTM relationship and I can't seem to adapt their answers.

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  • Getting list of all existing vtables.

    - by Patrick
    In my application I have quite some void-pointers (this is because of historical reasons, application was originally written in pure C). In one of my modules I know that the void-pointers points to instances of classes that could inherit from a known base class, but I cannot be 100% sure of it. Therefore, doing a dynamic_cast on the void-pointer might give problems. Possibly, the void-pointer even points to a plain-struct (so no vptr in the struct). I would like to investigate the first 4 bytes of the memory the void-pointer is pointing to, to see if this is the address of the valid vtable. I know this is platform, maybe even compiler-version-specific, but it could help me in moving the application forward, and getting rid of all the void-pointers over a limited time period (let's say 3 years). Is there a way to get a list of all vtables in the application, or a way to check whether a pointer points to a valid vtable, and whether that instance pointing to the vtable inherits from a known base class?

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  • Is Android reference at android.com good enough

    - by the100rabh
    Hi, I am a C++ developer, but have a fair idea of Java as I learnt it in college 5years ago. I have been trying to learn programming for android. But instead of rushing to buy books, I have tried to read through the Android Dev Guide and learn from there making use of the sample applications. Thats besides SO ofcourse. I am trying to make some apps based on ideas I have. So my question is, Is it suitable or possible to learn android programming this way. Or is there something that I will be missing in all this.

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  • what else to do to establish many-to-many associations in Ruby on Rails? thanks!

    - by john
    Hi, I have two classes and I want to establish a many-to-many assications, here is the code: class Category < ActiveRecord::Base has_and_belongs_to_many :events has_and_belongs_to_many :tips end class Tip < ActiveRecord::Base has_and_belongs_to_many :categories However, I kept getting the following errors and I would appreciate it if some one could educate me what is going wrong: PGError: ERROR: relation "categories_tips" does not exist : SELECT "categories".id FROM "categories" INNER JOIN "categories_tips" ON "categories".id = "categories_tips".category_id WHERE ("categories_tips".tip_id = NULL ) the viewer part: 4: <%= text_field :tip, :title %></label></p> 5: 6: <p><label>Categories<br/> 7: <%= select_tag('categories[]', options_for_select(Category.find(:all).collect {|c| [c.name, c.id] }, @tip.category_ids), :multiple => true ) %></label></p> 8: 9: <p><label>Location<br/> 10: <%= text_field_with_auto_complete :tip, :abstract %></label></p>

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  • Statically Init a derived class

    - by AC
    With c++, Is there a way to get a derived class to inherit its own static initializer? I am trying to do something like the following: class Base { public: class StaticInit { public: virtual StaticInit() =0; }; }; class Derived: public Base { public: virtual StaticInit::StaticInit() { //do something with the derived class } static StaticInit init; } static Derived::StaticInit init; it would also be nice if I didn't have to define the init var in each derived class. I am currently redefining the StaticInit internal class in each derived class but it seems redundant. Each derived class is a singleton, and I need the instance to be stored in a lookup table at program startup.

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  • What's the deal with all of the abstract stuff?

    - by JustVenting
    I see a lot of talk about MVVM, MVC, Design Patterns etc... You know, some guy has a blog, and he spent the last six months learning about one these things and desiging a program centered around that concept and then he goes on and on about it like its better than sliced bread. I read all of this crap and I wonder, whatever happened to simple logical programming? Not self-absorbed huge frameworks of design patterns and mvc and whatever else you can think of... just simple linear programming, perhaps a few classes to encapsulate things here and there.

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  • Erlang Question - Time order of messages

    - by Aiden Bell
    Read (skimmed enough to get coding) through Erlang Programming and Programming Erlang. One question, which is as simple as it sounds: If you have a process Pid1 on machine m1 and a billion million messages are sent to Pid1, are messages handled in parallel by that process (I get the impression no) and(answered below) is there any guarantee of order when processing messages? ie. Received in order sent? If so, how is clock skew handled in high traffic situations for ordering? Coming from the whole C/Thread pools/Shared State background ... I want to get this concrete. I understand distributing an application, but want to ensure the 'raw bones' are what I expect before building processes and distributing workload. Also, am I right in thinking the whole world is currently flicking through Erlang texts ;)

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  • undefined method `events' for #<ActiveRecord::Relation:0x4177518> -rails 3.0.3

    - by brg
    I am having this unexplained NoMethodError with undefined method `events' for #. I don't know why since my model association are well defined and the event table has the foreign keys for the user table. I tried using this fix but it failed: Rails 3 ActiveRecord::Relation random associations behavior event.rb class Event < ActiveRecord::Base belongs_to :user attr_accessible :event_name, :Starts_at, :finish, :tracks end user.rb class User < ActiveRecord::Base has_many :events, :dependent = :destroy attr_accessible :name, :event_attributes accepts_nested_attributes_for :events, :allow_destroy = true end schema.rb ActiveRecord::Schema.define(:version = 20101201180355) do create_table "events", :force = true do |t| t.string "event_name" t.string "tracks" t.datetime "starts_at" t.datetime "finish" t.datetime "created_at" t.datetime "updated_at" t.integer "user_id" end end error message NoMethodError in Users#index undefined method `events' for # Extracted source (around line #10): 7: <%= sortable "Tracks" % 8: 10: <% @users.events.each do |event| % 11: <% debugger % 12: 13: <%= event.starts_at % Trace of template inclusion: app/views/users/index.html.erb Rails.root: C:/rails_project1/events_manager Application Trace | Framework Trace | Full Trace app/views/users/_event_user.html.erb:10:in _app_views_users__event_user_html_erb__412443848_34308540_1390678' app/views/users/index.html.erb:7:in_app_views_users_index_html_erb___603337143_34316016_0'

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  • Capistrano deploy:migrate Could not find rake-0.9.2.2 in any of the sources

    - by Kyle
    My Capistrano deploy:migrate task is set to run a simple rake db:migrate command, as follows: env PATH=/home/user/.gems/bin sh -c 'cd /home/user/app/releases/20121003140503 && rake RAILS_ENV=production db:migrate' When I run this task during an ssh session manually it completes successfully. However when I run from my local development box, I receive the following error: ** [out :: app] Could not find rake-0.9.2.2 in any of the sources I am able to locate my rake gem by typing which rake via ssh (/home/user/.gems/bin/rake) and rake --version gives me "rake, version 0.9.2.2," so I don't understand why this command fails via Capistrano?

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  • How to avoid the Windows (XP) Security Warning when launching a "DOS" command line within C#?

    - by Will Marcouiller
    This question is related to this initial question asked a little while ago. Now, that I have chosen the extracting tool, I'm iterating through a given in command line parameter directory and subdirectories to extract the compressed .zip files. private static void ExtractAll(DirectoryInfo _workingFolder) { if(_workingFolder == null) { Console.WriteLine("Répertoire inexistant."); return; } foreach (DirectoryInfo subFolder in _workingFolder.GetDirectories("*", SearchOption.AllDirectories)) foreach(FileInfo zippedFile in subFolder.GetFiles("*.zip", SearchOption.AllDirectories)) { if(zippedFile.Exists) { ProcessStartInfo task = new ProcessStartInfo(@".\Tools\7za.exe", string.Format("x {0}", zippedFile.FullName)); Process.Start(task); } } } But everytime I start a 7za process, the Windows Security Warning prompts. I would like to avoid such annoying behaviour, so here's my question: How to avoid the Windows (XP) Security Warning when launching a "DOS" command line within C#?

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  • dependson option does not work in knitr?

    - by umair durrani
    Data File Name of the data file = toto.rmd Contains following: ##1st ```{r clock, cache=TRUE} x <- 600 x ``` ##2nd ```{r, cache=TRUE, cache.path="toto_cache/", dependson="clock"} x+5 ``` Problem The second chunk is not being updated. Previously x was 500, after updating it to 600, I get following after knit HTML in RSTUDIO: 1st x <- 600 x ## [1] 600 2nd x+5 ## [1] 505 What am I missing here? Session Info > sessionInfo() R version 3.0.3 (2014-03-06) Platform: x86_64-w64-mingw32/x64 (64-bit) locale: [1] LC_COLLATE=English_United States.1252 LC_CTYPE=English_United States.1252 [3] LC_MONETARY=English_United States.1252 LC_NUMERIC=C [5] LC_TIME=English_United States.1252 attached base packages: [1] stats graphics grDevices utils datasets methods base other attached packages: [1] ggplot2_0.9.3.1 loaded via a namespace (and not attached): [1] colorspace_1.2-3 dichromat_2.0-0 digest_0.6.4 evaluate_0.5.5 [5] formatR_0.10 grid_3.0.3 gtable_0.1.2 htmltools_0.2.4 [9] knitr_1.6 labeling_0.2 MASS_7.3-29 munsell_0.4.2 [13] plyr_1.8.1 proto_0.3-10 RColorBrewer_1.0-5 Rcpp_0.11.0 [17] reshape2_1.2.2 rmarkdown_0.2.64 scales_0.2.3 stringr_0.6.2 [21] tools_3.0.3 yaml_2.1.10 >

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  • C#: How to unit test a method that relies on another method within the same class?

    - by michael paul
    I have a class similar to the following: public class MyProxy : ClientBase<IService>, IService { public MyProxy(String endpointConfiguration) : base(endpointConfiguration) { } public int DoSomething(int x) { int result = DoSomethingToX(x); //This passes unit testing int result2 = ((IService)this).DoWork(x) //do I have to extract this part into a separate method just //to test it even though it's only a couple of lines? //Do something on result2 int result3 = result2 ... return result3; } int IService.DoWork(int x) { return base.Channel.DoWork(x); } } The problem lies in the fact that when testing I don't know how to mock the result2 item without extracting the part that gets result3 using result2 into a separate method. And, because it is unit testing I don't want to go that deep as to test what result2 comes back as... I'd rather mock the data somehow... like, be able to call the function and replace just that one call.

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  • % confuses python raw sql query

    - by Jonathan
    Following this SO question, I'm trying to "truncate" all tables related to a certain django application using the following raw sql commands in python: cursor.execute("set foreign_key_checks = 0") cursor.execute("select concat('truncate table ',table_schema,'.',table_name,';') as sql_stmt from information_schema.tables where table_schema = 'my_db' and table_type = 'base table' AND table_name LIKE 'some_prefix%'") for sql in [sql[0] for sql in cursor.fetchall()]: cursor.execute(sql) cursor.execute("set foreign_key_checks = 1") Alas I receive the following error: C:\dev\my_project>my_script.py Traceback (most recent call last): File "C:\dev\my_project\my_script.py", line 295, in <module> cursor.execute(r"select concat('truncate table ',table_schema,'.',table_name,';') as sql_stmt from information_schema.tables where table_schema = 'my_db' and table_type = 'base table' AND table_name LIKE 'some_prefix%'") File "C:\Python26\lib\site-packages\django\db\backends\util.py", line 18, in execute sql = self.db.ops.last_executed_query(self.cursor, sql, params) File "C:\Python26\lib\site-packages\django\db\backends\__init__.py", line 216, in last_executed_query return smart_unicode(sql) % u_params TypeError: not enough arguments for format string Is the % in the LIKE making trouble? How can I workaround it?

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  • Android application: showing overlay items in AsyncTask

    - by user1707887
    I am building an android application that uses google maps to overlay items. The latitude and longitude for the items I get from a MySQL database. To do this I connect to a php script using HTTP in Async Task. My code for displaying items on the map is in the onPostExecute() method of Async Task. Everything works fine but when I for example rotate the phone all my overlayed items disappear. How can I resolve this issue? Should overlaying the items happen in the main thread? If so, I need to somehow pass the information from the async taks to the main thread, which I have looked into but have not been able to get that working. If somebody knows a good and right way to do this, I would really appreciate the help.

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  • Overload and hide methods in Java

    - by Marco
    Hi, i have an abstract class BaseClass with a public insert() method: public abstract class BaseClass { public void insert(Object object) { // Do something } } which is extended by many other classes. For some of those classes, however, the insert() method must have additional parameters, so that they instead of overriding it I overload the method of the base class with the parameters required, for example: public class SampleClass extends BaseClass { public void insert(Object object, Long param){ // Do Something } } Now, if i instantiate the SampleClass class, i have two insert() methods: SampleClass sampleClass = new SampleClass(); sampleClass.insert(Object object); sampleClass.insert(Object object, Long param); what i'd like to do is to hide the insert() method defined in the base class, so that just the overload would be visible: SampleClass sampleClass = new SampleClass(); sampleClass.insert(Object object, Long param); Could this be done in OOP?

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  • How do I best write my own background-working and communicatible (sending progress updates and getti

    - by Ivan
    I have to develop a class which can run it's own hard-coded task in a background thread and communicate with container class sending him progress updates and taking messages from it. I believe I am going to extend BackgroundWorker class but it looks a bit weird to extend and I haven't managed to find a good example wit Google. Can you share a link to a good example of solving such a task? Please don't offer placing a BackgroundWorker visually on a form and reading the standard tutorial, it's not for my case. Maybe I'd better not extend but encapsulate a BackgroundWorker, but I hardly understand how to use it outide WinForms designer either :-(

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  • error msg in avr studio4

    - by shubhang
    i have recently purchased an AVR USB programmer from robokits.co.in, was trying to program atmeg8 using AVR studio4 and i get the following when i click on the program options: a problem occurred when executing the command. make sure u are using the correct programming method. current mode is ISP verify that the device is placed in the correct socket, and that the ISP cable is connected properly.check that the programming frequency specified in the main page is well below 1/4th of the clock frequency of the device. i have tried all that i could think of, i have checked the connections and the freq is below 1/4th of the device. but that doesn't solve this problem i have made the circuit for blinking LEDs program please help me out see the image for details thanking you

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  • Field contains foreign IDs for different tables

    - by Rich
    I am developing a php/mysql driven facebook game. I am stuck on an element the table design. When a user completes a task I want to trigger any number of events. I was thinking of something like so: tbl_events *event_id - serogate primary ID *task_id - foreign ID of the task just completed *event_type - what type of event e.g is it a facebook stream publish or a message to the user or does it unlock a new element of the game? *event_param - this is where it gets tricky... the event parameter is a problem for two reasons, 1) it will contain different foreign ids... dependent on the event_type and thus it will not be possible to join to x table. Meaning I would have to call two queries. 2) Most events require a single id or text, however some events require multiple parameters - like the facebook stream publish.

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  • Learning C++ from AS3

    - by grey
    I'm a decent AS3 programmer. I work in games, and that is my reason for programming. While there is much I can accomplish with Adobe AIR, my understanding at this point is that learning C++ is probably a good direction to take. I would learn a lot of valuable lower level programming if I needed it down the road, and I would have an easier time learning other C oriented languages. I see a lot of information for people looking to learn AS3 who know C++, but not the other way around. Why C++? Cross platform compatibility is important to me, so I'm not particularly interested in C# or Objective-C at this junction. I'm also aware of HaXe, and while I love the concept, after doing some research I'm worried about investing a lot of time into something so recent with limited learning resources and documentation. I'm looking for advice and resources (books, articles) related to this topic. Thanks in advance!

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