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• confused about how to use JSON in C#

  - by Josh

  The answer to just about every single question about using C# with json seems to be "use JSON.NET" but that's not the answer I'm looking for. the reason I say that is, from everything I've been able to read in the documentation, JSON.NET is basically just a better performing version of the DataContractSerializer built into the .net framework... Which means if I want to deserialize a JSON string, I have to define the full, strongly-typed class for EVERY request I might have. so if I have a need to get categories, posts, authors, tags, etc, I have to define a new class for every one of these things. This is fine if I built the client and know exactly what the fields are, but I'm using someone else's api, so I have no idea what the contract is unless I download a sample response string and create the class manually from the JSON string. Is that the only way it's done? Is there not a way to have it create a kind of hashtable that can be read with json["propertyname"]? Finally, if I do have to build the classes myself, what happens when the API changes and they don't tell me (as twitter seems to be notorious for doing)? I'm guessing my entire project will break until I go in and update the object properties... So what exactly is the general workflow when working with JSON? And by general I mean library-agnostic. I want to know how it's done in general, not specifically to a target library... I hope that made sense, this has been a very confusing area to get into... thanks!

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• MySQL 1064 error, works in command line and phpMyAdmin; not in app

  - by hundleyj

  Here is my query: select * from (select *, 3956 * 2 * ASIN(SQRT(POWER(SIN(RADIANS(45.5200077 - lat)/ 2), 2) + COS(RADIANS(45.5200077)) * COS(RADIANS(lat)) * POWER(SIN(RADIANS(-122.6942014 - lng)/2),2))) AS distance from stops order by distance, route asc) as p group by route, dir order by distance asc limit 10 This works fine at the command line and in PHPMyAdmin. I'm using Dbslayer to connect to MySQL via my JavaScript backend, and the request is returning a 1064 error. Here is the encoded DBSlayer request string: http://localhost:9090/db?{%22SQL%22:%22select%20*%20from%20%28select%20*,%203956%20*%202%20*%20ASIN%28SQRT%28POWER%28SIN%28RADIANS%2845.5200077%20-%20lat%29/%202%29,%202%29%20+%20COS%28RADIANS%2845.5200077%29%29%20*%20COS%28RADIANS%28lat%29%29%20*%20POWER%28SIN%28RADIANS%28-122.6942014%20-%20lng%29/2%29,2%29%29%29%20AS%20distance%20from%20%60stops%60%20order%20by%20%60distance%60,%20%60route%60%20asc%29%20as%20p%20group%20by%20%60route%60,%20%60dir%60%20order%20by%20%60distance%60%20asc%20limit%2010%22} And the response: {"MYSQL_ERRNO" : 1064 , "MYSQL_ERROR" : "You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '(RADIANS(45.5200077)) * COS(RADIANS(lat)) * POWER(SIN(RADIANS(-122.6942014 - lng' at line 1" , "SERVER" : "trimet"} Thanks!

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• Cant print contents of a custom file

  - by ZaZu

  Hello, Im trying to scan contents from a random file into an array in a structure. Then I want to print those contents on screen. (NOTE: The following code is from a bigger program, this is just a sample, but all structures and arrays used are needed as declared ) The contents of the file being tested are simply: 5 4 3 2 5 3 4 2 #include<stdio.h> #define first 500 #define sec 500 struct trial{ int f; int r; float what[first][sec]; }; int trialtest(trial *test); int trialdisplay(trial *test); main(){ trial test; trialtest(&test); trialdisplay(&test); } int trialtest(trial *test){ int z,x,i; FILE *inputf; inputf=fopen("randomfile.txt","r"); for(i=0;i<5;i++){ fscanf(inputf,"%f",&(*test).what[z][x]); } fclose(inputf); return 0; } int trialdisplay(trial *test){ int i,z,x; printf("printing\n\n\n"); for (i=0;i<10;i++){ printf("%f",(*test).what[z][x]); } return 0; } The problem is, I get this error whenever I run the code .. I cant really understand whats going on : Any suggestions ? Thanks alot !

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• eclipse show errors but compiles when external makefile

  - by Anthony

  I have some c++ code using CImg and Eigen libraries. At the c++ code I define a plugin like this #define cimg_plugin1 "my_plugin.h" #include "CImg.h" The plugin contains many method definitions that are used at the c++ code. I also have a makefile that when called from the command line (./make), allows me to compile everything, and generates an executable. I want to import this code into a new Eclipse project, and I do it so: NewProjectC++ projectmakefile projectempty project unmark "Use default location", and select the folder containing my code at the filesystem ProjectpropertiesC/C++ Buildunmark "Use default build command" and set it to use my makefile Also in project propertiesC/C++ GeneralPaths and SymbolsAdd paths to folders containing Eigen and CImg Rebuild index Clean project Restart eclipse When I build the project, eclipse tells me I have more than 1000 errors in "my_plugin.h", but it is capable to generate the executable. Even though, I would like to get rid of this errors, because they are annoying. Also, if I want to open the declaration of CImg methods used at the plugin, I can't. I know it has been asked before, but any of the solutions I found were satisfactory for me (most of them enumerated at the previous list). The sources I visited are the following, and I would be really happy if you find and tell me others I didn't see. Eclipse shows errors but project compile fine eclipse C project shows errors (Symbol could not be resolved) but it compiles Eclipse CDT shows some errors, but the project is successfully built http://www.eclipse.org/forums/index.php/t/247954/

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• Dynamic stack allocation in C++

  - by Poni

  I want to allocate memory on the stack. Heard of _alloca / alloca and I understand that these are compiler-specific stuff, which I don't like. So, I came-up with my own solution (which might have it's own flaws) and I want you to review/improve it so for once and for all we'll have this code working: /*#define allocate_on_stack(pointer, size) \ __asm \ { \ mov [pointer], esp; \ sub esp, [size]; \ }*/ /*#define deallocate_from_stack(size) \ __asm \ { \ add esp, [size]; \ }*/ void test() { int buff_size = 4 * 2; char *buff = 0; __asm { // allocate mov [buff], esp; sub esp, [buff_size]; } // playing with the stack-allocated memory for(int i = 0; i < buff_size; i++) buff[i] = 0x11; __asm { // deallocate add esp, [buff_size]; } } void main() { __asm int 3h; test(); } Compiled with VC9. What flaws do you see in it? Me for example, not sure that subtracting from ESP is the solution for "any kind of CPU". Also, I'd like to make the commented-out macros work but for some reason I can't.

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• Doctrine/symfony: getSqlQuery() output in phpMyAdmin/SQL tab

  - by user248959

  Hi, i have created this query that works OK: $q1 = Doctrine_Query::create() ->from('Usuario u') ->leftJoin('u.AmigoUsuario a ON u.id = a.user2_id OR u.id = a.user1_id') ->where("a.user2_id = ? OR a.user1_id = ?", array($id,$id)) ->andWhere("u.id <> ?", $id) ->andWhere("a.estado LIKE ?", 1); echo $q1->getSqlQuery(); The calling to getSqlQuery outputs this clause: SELECT s.id AS s_id, s.username AS s_username, s.algorithm AS s_algorithm, s.salt AS s_salt, s.password AS s__password, s.is_active AS s__is_active, s.is_super_admin AS s__is_super_admin, s.last_login AS s__last_login, s.email_address AS s__email_address, s.nombre_apellidos AS s__nombre_apellidos, s.sexo AS s__sexo, s.fecha_nac AS s__fecha_nac, s.provincia AS s_provincia, s.localidad AS s_localidad, s.fotografia AS s_fotografia, s.avatar AS s_avatar, s.avatar_mensajes AS s__avatar_mensajes, s.created_at AS s__created_at, s.updated_at AS s__updated_at, a.id AS a__id, a.user1_id AS a__user1_id, a.user2_id AS a__user2_id, a.estado AS a__estado FROM sf_guard_user s LEFT JOIN amigo_usuario a ON ((s.id = a.user2_id OR s.id = a.user1_id)) WHERE ((a.user2_id = ? OR a.user1_id = ?) AND s.id < ? AND a.estado LIKE ?) If i take that clause to phpmyadmin SQL tab i get this error 1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '? OR a.user1_id = ?) AND s.id < ? AND a.estado LIKE ?) LIMIT 0, 30' at line 1 Why i'm getting this error? Regards Javi

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• How do I use a custom cookie session serializer in Rack?

  - by Damien Wilson

  Hello SO. I'm currently integrating Warden into a new Rack application I'm building. I'd like to implement a recent patch to Rack that allows me to specify how sessions are serialized; specifically, I'd like to use Rack::Session::Cookie::Identity as the session processor. Unfortunately, the documentation is a little unclear as to what syntax I should use to configure Rack::Session::Cookie in my rackup file, can anyone here tell me what I'm doing wrong? config.ru require 'my_sinatra_app' app = self use Rack::Session::Cookie.new(app, Rack::Session::Cookie::Identity.new), {:key => "auth_token"} use Warden::Manager do |warden| # Must come AFTER Rack::Session warden.default_strategies :password warden.failure_app Jelli::Auth.run! end run MySinatraApp error message from thin !! Unexpected error while processing request: undefined method `new' for #<Rack::Session::Cookie:0x00000110124128> PS: I'm using bundler to manage my gem dependencies and I've likewise included rack's master branch as the desired version. Update: As suggested in the comments below, I have read the documentation; sadly the suggested syntax in the docs is not working. Update: Still no luck on my end; offering up a bounty to whoever can help me figure this out.

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• templete class c++

  - by inna karpasas

  hi! i try to design a templete for my universty project. i wrote the follwing cod: #ifndef _LinkedList_H_ #define _LinkedList_H_ #include "Link.h" #include <ostream> template <class L>//error one class LinkedList { private: Link<L> *pm_head; Link<L> * pm_tail; int m_numOfElements; Link<L>* FindLink(L * dataToFind); public: LinkedList(); ~LinkedList(); int GetNumOfElements(){return m_numOfElements;} bool Add( L * data); L *FindData(L * data); template <class L> friend ostream & operator<<(ostream& os,const LinkedList<L> listToprint);//error two L* GetDataOnTop(); bool RemoveFromHead(); L* Remove(L * toRemove); this templete uses the link class templete #ifndef _Link_H_ #define _Link_H_ template <class T>//error 3 class Link { private: T* m_data; Link* m_next; Link* m_prev; public: Link(T* data); ~Link(void); bool Link::operator ==(const Link& other)const; /*getters*/ Link* GetNext()const {return m_next;} Link* GetPrev()const {return m_prev;} T* GetData()const {return m_data;} //setters void SetNext(Link* next) {m_next = next;} void SetPrev(Link* prev) {m_prev = prev;} void SetData(T* data) {m_data = data;} }; error one: shadows template parm class L' error two:declaration ofclass L' error three: shadows template parm `class T' i dont understand what is the problem. i can relly usr your help thank you :)

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• Creating an appropriate index for a frequently used query in SQL Server

  - by Slauma

  In my application I have two queries which will be quite frequently used. The Where clauses of these queries are the following: WHERE FieldA = @P1 AND (FieldB = @P2 OR FieldC = @P2) and WHERE FieldA = @P1 AND FieldB = @P2 P1 and P2 are parameters entered in the UI or coming from external datasources. FieldA is an int and highly on-unique, means: only two, three, four different values in a table with say 20000 rows FieldB is a varchar(20) and is "almost" unique, there will be only very few rows where FieldB might have the same value FieldC is a varchar(15) and also highly distinct, but not as much as FieldB FieldA and FieldB together are unique (but do not form my primary key, which is a simple auto-incrementing identity column with a clustered index) I'm wondering now what's the best way to define an index to speed up specifically these two queries. Shall I define one index with... FieldB (or better FieldC here?) FieldC (or better FieldB here?) FieldA ... or better two indices: FieldB FieldA and FieldC FieldA Or are there even other and better options? What's the best way and why? Thank you for suggestions in advance!

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• Is it possible to create a python iterator over pre-defined mutable data?

  - by Wilduck

  I might be doing this wrong, if I am, let me know, but I'm curious if the following is possible: I have a class that holds a number of dictionaries, each of which pairs names to a different set of objects of a given class. For example: items = {"ball" : ItemInstance1, "sword" : ItemInstance2} people = {"Jerry" : PersonInstance1, "Bob" : PersonInstance2, "Jill" : PersonInstance3} My class would then hold the current items and people that are availible, and these would be subject to change as the state changes: Class State: def __init__(self, items, people): self.items = items self.people = people I would like to define a iter() and next() method such that it iterates through all of the values in its attributes. My first question is whether or not this is possible. If it is, will it be able to support a situation as follows: I define items and people as above then: state = State(items, people) for names, thing in state: print name + " is " + thing.color items[cheese] = ItemInstance3 for names, thing in state: print name + " weighs " + thing.weight While I feel like this would be usefull in the code I have, I don't know if it's either possible or the right approach. Everything I've read about user defined iterators has suggested that each instance of them is one use only.

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• key-words highlight in <textarea> (again)

  - by Halst

  Wait, I know! I know that this "syntax highlight in textarea"-question was raised like a million times on stackoverflow! But, please, listen. offtopic: I'm not a web-developer, and technically I'm not a programmer at all. I study mechatronics and deal mostly with control-engineering and digital-hardware. And I'm so pissed off that whenever I want to share some application (that would be helpful in my field) and embed it into the web, I need to know such a crazy amount of technologies, like html, css, javascript, flash, etc.. that takes time, which I could have been spending for the benefit of my own field. Right now I'm playing with hardware-description-languages and I'm writing some Python-libraries to convert one HDL into another. And I wanted to embed such feature on the web: http://xhdl2vhdl.appspot.com/ I wanted to implement some basic syntax highlighting (only keywords highlighting will be enough) so that the code could be readable. But the whole idea highlighting something in textarea is not trivial at all. The other difficulty is that the languages I work with are rare, and there are no out-of-box solutions for them. I tried to dig into these solutions, but they are very complicated for me: http://www.nicolarizzo.com/gamesroom/experimental/CodeEditor.html http://marijn.haverbeke.nl/codemirror/jstest.html and there is no clear descriptions how to use them (for my level of knowledge of web-development). So, is there a simple solution, just to highlight a bunch of key-words in textarea or perform something equivalent? Thank you.

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• Linq merging results

  - by glenneroo

  I'm working with a list within a list. This is how I'm currently searching: var tags = from fd in BigList from tag in fd.Tags where tag.Id == selectedTag.Id || tag.Id == ID.TIMESTAMP select new { fd.Name, tag.Id, tag.Value }; I then iterate over the result-set and remembering when Timestamp pops up for the next entry, needless to say this is sloppy and I'm positive there's a better way using Linq, I just can't seem to find the syntax. Here's some sample output (Id indicates what type of data is stored inside e.g. a timestamp): Name | Id | Value -----|----|---------- 0000 | 1 | <timestamp> 0000 | 2 | 1.2 ... 9999 | 1 | <timestamp> 9999 | 2 | 6.3 I need all instances where Id = selectedTag.Id. I just want 1 list with Name, Id, Value and Timestamp, but the problem is my above attempt returns 2 entries for every item (1 for timestamp and 1 for the value). Is there a way to do this using Linq? Preferably using query syntax! :)

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• Programatically enable/disable menuBar buttons in Flex 4

  - by Hamid

  I have the following XML in my Flex4 (AIR) project that defines the start of my menu interface: <mx:MenuBar x="0" y="0" width="100%" id="myMenuBar" labelField="@label" itemClick="menuChange(event)"> <mx:dataProvider> <s:XMLListCollection> <fx:XMLList xmlns=""> <menu label="File"> <item label="New"/> <item label="Load"/> <item label="Save" enabled="false"/> </menu> <menu label="Help"> <item label="About"/> </menu> </fx:XMLList> </s:XMLListCollection> </mx:dataProvider> </mx:MenuBar> I am trying to find the syntax that will let me set the save button to enabled=true after a file has been loaded by clicking "Load", however I can't figure out the syntax, can someone make a suggestion please. Currently the way that button clicks are detected is by a Switch/Case testing the String result of the MenuEvent event.item.@label. Maybe this isn't the best way?

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• An online php debugger/code editor

  - by Zirak

  It's a simple deal: I'm sometimes in places where I don't have my laptop, and find myself with spare time and an idea for a project. But unfortunately, I can't do anything about it. I tried a variety of solutions, which include running IDEs (like phpstorm or Aptana) on a disc-on-key or cd (very slow and unappealing), trying several online solutions (like http://phpanywhere.net) and found that all of them are either buggy, overloaded or underloaded with features, just difficult to use, require FTP etc etc. All that is required here is a syntax highlighting and debugging alerts; no actual running of code. So the question is split into two: 1)Do you know of a good online php editor that you've used and enjoyed? 2)If no, then how would you go about making one? The second one seems a bit general, so I'll try and expand...It might be a good idea; if you can't find one, make one. The question is about the concept of making a syntax highlighter (shouldn't be too difficult), and the difficult part of catching php errors WITHOUT executing any php code. Thank you in advance.

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• Mutual class instances in C++

  - by SepiDev

  Hi guys. What is the issue with this code? Here we have two files: classA.h and classB.h classA.h: #ifndef _class_a_h_ #define _class_a_h_ #include "classB.h" class B; //???? class A { public: A() { ptr_b = new B(); //???? } virtual ~A() { if(ptr_b) delete ptr_b; //???? num_a = 0; } int num_a; B* ptr_b; //???? }; #endif //_class_a_h_ classB.h: #ifndef _class_b_h_ #define _class_b_h_ #include "classA.h" class A; //???? class B { public: B() { ptr_a = new A(); //???? num_b = 0; } virtual ~B() { if(ptr_a) delete ptr_a; //???? } int num_b; A* ptr_a; //???? }; #endif //_class_b_h_ when I try to compile it, the compiler (g++) says: classB.h: In constructor ‘B::B()’: classB.h:12: error: invalid use of incomplete type ‘struct A’ classB.h:6: error: forward declaration of ‘struct A’ classB.h: In destructor ‘virtual B::~B()’: classB.h:16: warning: possible problem detected in invocation of delete operator: classB.h:16: warning: invalid use of incomplete type ‘struct A’ classB.h:6: warning: forward declaration of ‘struct A’ classB.h:16: note: neither the destructor nor the class-specific operator delete will be called, even if they are declared when the class is defined.

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• How to eliminate duplicate rows?

  - by Odette

  hi guys im back with my original query and i just have one question please (ps: I know i have to vote and regsiter and I promise I will do that today) With the following query (t-sql) I am getting the correct results, except that there are duplicates now. I have been reading up and think I can use the PARTITION BY syntax - can you please show me how to incorporate the PARTITION BY syntax? WITH CALC1 AS (SELECT OTQUOT, OTIT01 AS ITEMS, ROUND(OQCQ01 * OVRC01,2) AS COST FROM @[email protected] WHERE OTIT01 < '' UNION ALL ... SELECT OTQUOT, OTIT10 AS ITEMS, ROUND(OQCQ10 * OVRC10,2) AS COST FROM @[email protected] WHERE OTIT10 < '' ) SELECT OTQUOT, DESC, ITEMS, RN FROM ( SELECT OTQUOT, ITEMS, B.IXRPGP AS GROUP, C.OTRDSC AS DESC, COST, ROW_NUMBER() OVER (PARTITION BY OTQUOT ORDER BY COST DESC) AS RN FROM CALC1 AS A INNER JOIN @[email protected] AS B ON (A.ITEMS = B.IKITMC) INNER JOIN DATAGRP.GDSGRP AS C ON (B.IXRPGP = C.OKRPGP) ) T RESULTS: 60408169 FENCING GNCPDCTP18BGBG 1 60408169 FENCING CGIFESHPD1795BG 2 60408169 FENCING GTTCGIBG 3 60408169 FENCING GBTCGIBG 4 How do I get rid of the duplicates? thanks Bill and all the others for your help (I am still learning!)

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• implementing cryptographic algorithms, specifically the key expansion part

  - by masseyc

  Hey, recently I picked up a copy of Applied Cryptography by Bruce Schneier and it's been a good read. I now understand how several algorithms outlined in the book work, and I'd like to start implementing a few of them in C. One thing that many of the algorithms have in common is dividing an x-bit key, into several smaller y-bit keys. For example, blowfish's key, X, is 64-bits, but you are required to break it up into two 32-bit halves; Xl and Xr. This is where I'm getting stuck. I'm fairly decent with C, but I'm not the strongest when it comes to bitwise operators and the like. After some help on IRC, I managed to come up with these two macros: #define splitup(a, b, c) {b = a >> 32; c = a & 0xffffffff; } #define combine(a, b, c) {a = (c << 32) | a;} Where a is 64 bits and b and c are 32 bits. However, the compiler warns me about the fact that I'm shifting a 32 bit variable by 32 bits. My questions are these: what's bad about shifting a 32-bit variable 32 bits? I'm guessing it's undefined, but these macros do seem to be working. Also, would you suggest I go about this another way? As I said, I'm fairly familiar with C, but bitwise operators and the like still give me a headache.

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• getting data from dynamic schema

  - by coure2011

  I am using mongoose/nodejs to get data as json from mongodb. For using mongoose I need to define schema first like this var mongoose = require('mongoose'); var Schema = mongoose.Schema; var GPSDataSchema = new Schema({ createdAt: { type: Date, default: Date.now } ,speed: {type: String, trim: true} ,battery: { type: String, trim: true } }); var GPSData = mongoose.model('GPSData', GPSDataSchema); mongoose.connect('mongodb://localhost/gpsdatabase'); var db = mongoose.connection; db.on('open', function() { console.log('DB Started'); }); then in code I can get data from db like GPSData.find({"createdAt" : { $gte : dateStr, $lte: nextDate }}, function(err, data) { res.writeHead(200, { "Content-Type": "application/json", "Access-Control-Allow-Origin": "*" }); var body = JSON.stringify(data); res.end(body); }); How to define scheme for a complex data like this, you can see that subSection can go to any deeper level. [ { 'title': 'Some Title', 'subSection': [{ 'title': 'Inner1', 'subSection': [ {'titile': 'test', 'url': 'ab/cd'} ] }] }, .. ]

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• Checking if any of a list of values falls within a table of ranges

  - by Conspicuous Compiler

  I'm looking to check whether any of a list of integers fall in a list of ranges. The ranges are defined in a table defined something like: # Extra Type Field Default Null Key 0 int(11) rangeid 0 NO PRI 1 int(11) max 0 NO MUL 2 int(11) min 0 NO MUL Using MySQL 5.1 and Perl 5.10. I can check whether a single value, say 7, is in any of the ranges with a statement like SELECT 1 FROM range WHERE 7 BETWEEN min AND max If 7 is in any of those ranges, I get a single row back. If it isn't, no rows are returned. Now I have a list of, say, 50 of these values, not stored in a table at present. I assemble them using map: my $value_list = '(' . ( join ', ', map { int $_ } @values ) . ')' ; I want to see if any of the items in the list fall inside of any of the ranges, but am not particularly concerned with which number nor which range. I'd like to use a syntax such as: SELECT 1 FROM range WHERE (1, 2, 3, 4, 5, 6, 7, 42, 309, 10000) BETWEEN min AND max MySQL kindly chastises me for such syntax: Operand should contain 1 column(s) I pinged #mysql who were quite helpful. However, having already written this up by the time they responded and thinking it'd be helpful to fix the answer in a more permanent medium, I figured I'd post the question anyhow. Maybe SO will provide a different solution?

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• No idea how to solve SICP exercise 1.11

  - by Javier Badia

  This is not homework. Exercise 1.11: A function f is defined by the rule that f(n) = n if n<3 and f(n) = f(n - 1) + 2f(n - 2) + 3f(n - 3) if n 3. Write a procedure that computes f by means of a recursive process. Write a procedure that computes f by means of an iterative process. Implementing it recursively is simple enough. But I couldn't figure out how to do it iteratively. I tried comparing with the Fibonacci example given, but I didn't know how to use it as an analogy. So I gave up (shame on me) and Googled for an explanation, and I found this: (define (f n) (if (< n 3) n (f-iter 2 1 0 n))) (define (f-iter a b c count) (if (< count 3) a (f-iter (+ a (* 2 b) (* 3 c)) a b (- count 1)))) After reading it, I understand the code and how it works. But what I don't understand is the process needed to get from the recursive defintion of the function to this. I don't get how the code formed in someone's head. Could you explain the thought process needed to arrive at the solution?

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• Initialize Static Array of Structs in C

  - by russell_h

  I implementing a card game in C. There are lots of types of cards and each has a bunch of information, including some actions that will need to be individually scripted associated with it. Given a struct like this (and I'm not certain I have the syntax right for the function pointer) struct CARD { int value; int cost; // This is a pointer to a function that carries out actions unique // to this card int (*do_actions) (struct GAME_STATE *state, int choice1, int choice2); }; I would like to initialize a static array of these, one for each card. I'm guessing this would look something like this int do_card0(struct GAME_STATE *state, int choice1, int choice2) { // Operate on state here } int do_card1(struct GAME_STATE *state, int choice1, int choice2) { // Operate on state here } extern static struct cardDefinitions[] = { {0, 1, do_card0}, {1, 3, do_card1} }; Will this work, and am I going about this the right way at all? I'm trying to avoid huge numbers of switch statements. Do I need to define the 'do_cardN' functions ahead of time, or is there some way to define them inline in the initialization of the struct (something like a lambda function in python)? I'll need read-only access to cardDefinitions from a different file - is 'extern static' correct for that? I know this is a lot of questions rolled into one but I'm really a bit vague about how to go about this. Thanks.

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• SQLAlchemy & Complex Queries

  - by user356594

  I have to implement ACL for an existing application. So I added the a user, group and groupmembers table to the database. I defined a ManyToMany relationship between user and group via the association table groupmembers. In order to protect some ressources of the app (i..e item) I added a additional association table auth_items which should be used as an association table for the ManyToMany relationship between groups/users and the specific item. item has following columns: user_id -- user table group_id -- group table item_id -- item table at least on of user_id and group_id columns are set. So it's possible to define access for a group or for a user to a specific item. I have used the AssociationProxy to define the relationship between users/groups and items. I now want to display all items which the user has access to and I have a really hard time doing that. Following criteria are used: All items which are owned by the user should be shown (item.owner_id = user.id) All public items should be shown (item.access = public) All items which the user has access to should be shown (auth_item.user_id = user.id) All items which the group of the user has access to should be shown. The first two criteria are quite straightforward, but I have a hard time doing the 3rd one. Here is my approach: clause = and_(item.access == 'public') if user is not None: clause = or_(clause,item.owner == user,item.users.contains(user),item.groups.contains(group for group in user.groups)) The third criteria produces an error. item.groups.contains(group for group in user.groups) I am actually not sure if this is a good approach at all. What is the best approach when filtering manytomany relationships? How I can filter a manytomany relationship based on another list/relationship? Btw I am using the latest sqlalchemy (6.0) and elixir version Thanks for any insights.

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• C# Event Handlers Using an Enum

  - by Jimbo

  I have a StatusChanged event that is raised by my object when its status changes - however, the application needs to carry out additional actions based on what the new status is. e.g If the new status is Disconnected, then it must update the status bar text and send an email notification. So, I wanted to create an Enum with the possible statuses (Connected, Disconnected, ReceivingData, SendingData etc.) and have that sent with the EventArgs parameter of the event when it is raised (see below) Define the object: class ModemComm { public event CommanderEventHandler ModemCommEvent; public delegate void CommanderEventHandler(object source, ModemCommEventArgs e); public void Connect() { ModemCommEvent(this, new ModemCommEventArgs ModemCommEventArgs.eModemCommEvent.Connected)); } } Define the new EventArgs parameter: public class ModemCommEventArgs : EventArgs{ public enum eModemCommEvent { Idle, Connected, Disconnected, SendingData, ReceivingData } public eModemCommEvent eventType { get; set; } public string eventMessage { get; set; } public ModemCommEventArgs(eModemCommEvent eventType, string eventMessage) { this.eventMessage = eventMessage; this.eventType = eventType; } } I then create a handler for the event in the application: ModemComm comm = new ModemComm(); comm.ModemCommEvent += OnModemCommEvent; and private void OnModemCommEvent(object source, ModemCommEventArgs e) { } The problem is, I get a 'Object reference not set to an instance of an object' error when the object attempts to raise the event. Hoping someone can explain in n00b terms why and how to fix it :)

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• Commenting out portions of code in Scala

  - by akauppi

  I am looking for a C(++) #if 0 -like way of being able to comment out whole pieces of Scala source code, for keeping around experimental or expired code for a while. I tried out a couple of alternatives and would like to hear what you use, and if you have come up with something better? // Simply block-marking N lines by '//' is one way... // <tags> """ anything My editor makes this easy, but it's not really The Thing. It gets easily mixed with actual one-line comments. Then I figured there's native XML support, so: <!-- ... did not work --> Wrapping in XML works, unless you have <tags> within the block: class none { val a= <ignore> ... cannot have //<tags> <here> (not even in end-of-line comments!) </ignore> } The same for multi-line strings seems kind of best, but there's an awful lot of boilerplate (not fashionable in Scala) to please the compiler (less if you're doing this within a class or an object): object none { val ignore= """ This seems like ... <truly> <anything goes> but three "'s of course """ } The 'right' way to do this might be: /*** /* ... works but not properly syntax highlighed in SubEthaEdit (or StackOverflow) */ ***/ ..but that matches the /* and */ only, not i.e. /*** to ***/. This means the comments within the block need to be balanced. And - the current Scala syntax highlighting mode for SubEthaEdit fails miserably on this. As a comparison, Lua has --[==[ matching ]==] and so forth. I think I'm spoilt? So - is there some useful trick I'm overseeing?

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• Migrate Data and Schema from MySQL to MSSQL

  - by colithium

  Are there any free solutions for automatically migrating a database from MySQL to MSSQL Server that "just works"? I've been attempting this simple (at least I thought so) task all day now. I've tried: MSSQL Server Management Studio's Import Data feature Create an empty database Tasks - Import Data... .NET Framework Data Provider for Odbc Valid DSN (verified it connects) Copy data from one or more tables or views Check 1 VERY simple table Click Preview Get Error: The preview data could not be retrieved. ADDITIONAL INFORMATION: ERROR [42000] [MySQL][ODBC 5.1 Driver][mysqld-5.1.45-community]You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '"table_name"' at line 1 (myodbc5.dll) A similar error occurs if I go through the rest of the wizard and perform the operation. The failed step is "Setting Source Connection" the error refers to retrieving column information and then lists the above error. It can retrieve column information just fine when I modify column mappings so I really don't know what the issue is. I've also tried getting various MySql tools to output ddl statements that MSSQL understand but haven't succeeded. I've tried with MySQL v5.1.11 to SQL Server 2005 and with MySQL v5.1.45 to SQL Server 2008 (with ODBC drivers 3.51.27.00 and 5.01.06.00 respectively)

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