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  • How to pass an anonymous array of strings to a JavaScript function?

    - by abatishchev
    I want to pass to an array of controls' IDs to a javascript script function so it will switch control's enable state. For example, in C# it would be like this: func(false, new[] { "Control1", "Control2", "Control3" }); In that function I want to find corresponding controls and disable/enable them. For one control I do this next way: <script type="text/javascript" language="javascript"> function switchControls(value, arr) { for (var n = 0; n < array.length; n++) document.getElementById(n).disabled = value; } </script> <asp:CheckBox runat="server" onclick="switchControls(this.checked, [ '<%= Control1.ClientID %>', '<%= Control2.ClientID %>' ])" Text="Take?" /> How to implement this properly? Have I to use jQuery?

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  • How to determine if two strings are sufficiently close?

    - by A.06
    We say that we can "hop" from the word w1 to the word w2 if they are "sufficiently close". We define w2 to be sufficiently close to w1 if one of the following holds: w2 is obtained from w1 by deleting one letter. w2 is obtained from w1 by replacing one of the letters in w1 by some letter that appears to its right in w1 and which is also to its right in alphabetical order. I have no idea how to check if 2. is fulfilled. To check if 1. is possible this is my function: bool check1(string w1, string w2){ if(w2.length - w1.length != 1){ return false; } for(int i = 0,int j = 0;i < w2.length;i++;j++){ if(w2[i] == w1[j]){//do nothing } else if(i == j){ j++; } else{ return false; } } return true; } Given two words w1 and w2, how do we check if we can 'hop' from w1 to w2?

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  • T-SQL Tuesday #33: Trick Shots: Undocumented, Underdocumented, and Unknown Conspiracies!

    - by Most Valuable Yak (Rob Volk)
    Mike Fal (b | t) is hosting this month's T-SQL Tuesday on Trick Shots.  I love this choice because I've been preoccupied with sneaky/tricky/evil SQL Server stuff for a long time and have been presenting on it for the past year.  Mike's directives were "Show us a cool trick or process you developed…It doesn’t have to be useful", which most of my blogging definitely fits, and "Tell us what you learned from this trick…tell us how it gave you insight in to how SQL Server works", which is definitely a new concept.  I've done a lot of reading and watching on SQL Server Internals and even attended training, but sometimes I need to go explore on my own, using my own tools and techniques.  It's an itch I get every few months, and, well, it sure beats workin'. I've found some people to be intimidated by SQL Server's internals, and I'll admit there are A LOT of internals to keep track of, but there are tons of excellent resources that clearly document most of them, and show how knowing even the basics of internals can dramatically improve your database's performance.  It may seem like rocket science, or even brain surgery, but you don't have to be a genius to understand it. Although being an "evil genius" can help you learn some things they haven't told you about. ;) This blog post isn't a traditional "deep dive" into internals, it's more of an approach to find out how a program works.  It utilizes an extremely handy tool from an even more extremely handy suite of tools, Sysinternals.  I'm not the only one who finds Sysinternals useful for SQL Server: Argenis Fernandez (b | t), Microsoft employee and former T-SQL Tuesday host, has an excellent presentation on how to troubleshoot SQL Server using Sysinternals, and I highly recommend it.  Argenis didn't cover the Strings.exe utility, but I'll be using it to "hack" the SQL Server executable (DLL and EXE) files. Please note that I'm not promoting software piracy or applying these techniques to attack SQL Server via internal knowledge. This is strictly educational and doesn't reveal any proprietary Microsoft information.  And since Argenis works for Microsoft and demonstrated Sysinternals with SQL Server, I'll just let him take the blame for it. :P (The truth is I've used Strings.exe on SQL Server before I ever met Argenis.) Once you download and install Strings.exe you can run it from the command line.  For our purposes we'll want to run this in the Binn folder of your SQL Server instance (I'm referencing SQL Server 2012 RTM): cd "C:\Program Files\Microsoft SQL Server\MSSQL11\MSSQL\Binn" C:\Program Files\Microsoft SQL Server\MSSQL11\MSSQL\Binn> strings *sql*.dll > sqldll.txt C:\Program Files\Microsoft SQL Server\MSSQL11\MSSQL\Binn> strings *sql*.exe > sqlexe.txt   I've limited myself to DLLs and EXEs that have "sql" in their names.  There are quite a few more but I haven't examined them in any detail. (Homework assignment for you!) If you run this yourself you'll get 2 text files, one with all the extracted strings from every SQL DLL file, and the other with the SQL EXE strings.  You can open these in Notepad, but you're better off using Notepad++, EditPad, Emacs, Vim or another more powerful text editor, as these will be several megabytes in size. And when you do open it…you'll find…a TON of gibberish.  (If you think that's bad, just try opening the raw DLL or EXE file in Notepad.  And by the way, don't do this in production, or even on a running instance of SQL Server.)  Even if you don't clean up the file, you can still use your editor's search function to find a keyword like "SELECT" or some other item you expect to be there.  As dumb as this sounds, I sometimes spend my lunch break just scanning the raw text for anything interesting.  I'm boring like that. Sometimes though, having these files available can lead to some incredible learning experiences.  For me the most recent time was after reading Joe Sack's post on non-parallel plan reasons.  He mentions a new SQL Server 2012 execution plan element called NonParallelPlanReason, and demonstrates a query that generates "MaxDOPSetToOne".  Joe (formerly on the Microsoft SQL Server product team, so he knows this stuff) mentioned that this new element was not currently documented and tried a few more examples to see what other reasons could be generated. Since I'd already run Strings.exe on the SQL Server DLLs and EXE files, it was easy to run grep/find/findstr for MaxDOPSetToOne on those extracts.  Once I found which files it belonged to (sqlmin.dll) I opened the text to see if the other reasons were listed.  As you can see in my comment on Joe's blog, there were about 20 additional non-parallel reasons.  And while it's not "documentation" of this underdocumented feature, the names are pretty self-explanatory about what can prevent parallel processing. I especially like the ones about cursors – more ammo! - and am curious about the PDW compilation and Cloud DB replication reasons. One reason completely stumped me: NoParallelHekatonPlan.  What the heck is a hekaton?  Google and Wikipedia were vague, and the top results were not in English.  I found one reference to Greek, stating "hekaton" can be translated as "hundredfold"; with a little more Wikipedia-ing this leads to hecto, the prefix for "one hundred" as a unit of measure.  I'm not sure why Microsoft chose hekaton for such a plan name, but having already learned some Greek I figured I might as well dig some more in the DLL text for hekaton.  Here's what I found: hekaton_slow_param_passing Occurs when a Hekaton procedure call dispatch goes to slow parameter passing code path The reason why Hekaton parameter passing code took the slow code path hekaton_slow_param_pass_reason sp_deploy_hekaton_database sp_undeploy_hekaton_database sp_drop_hekaton_database sp_checkpoint_hekaton_database sp_restore_hekaton_database e:\sql11_main_t\sql\ntdbms\hekaton\sqlhost\sqllang\hkproc.cpp e:\sql11_main_t\sql\ntdbms\hekaton\sqlhost\sqllang\matgen.cpp e:\sql11_main_t\sql\ntdbms\hekaton\sqlhost\sqllang\matquery.cpp e:\sql11_main_t\sql\ntdbms\hekaton\sqlhost\sqllang\sqlmeta.cpp e:\sql11_main_t\sql\ntdbms\hekaton\sqlhost\sqllang\resultset.cpp Interesting!  The first 4 entries (in red) mention parameters and "slow code".  Could this be the foundation of the mythical DBCC RUNFASTER command?  Have I been passing my parameters the slow way all this time? And what about those sp_xxxx_hekaton_database procedures (in blue)? Could THEY be the secret to a faster SQL Server? Could they promise a "hundredfold" improvement in performance?  Are these special, super-undocumented DIB (databases in black)? I decided to look in the SQL Server system views for any objects with hekaton in the name, or references to them, in hopes of discovering some new code that would answer all my questions: SELECT name FROM sys.all_objects WHERE name LIKE '%hekaton%' SELECT name FROM sys.all_objects WHERE object_definition(OBJECT_ID) LIKE '%hekaton%' Which revealed: name ------------------------ (0 row(s) affected) name ------------------------ sp_createstats sp_recompile sp_updatestats (3 row(s) affected)   Hmm.  Well that didn't find much.  Looks like these procedures are seriously undocumented, unknown, perhaps forbidden knowledge. Maybe a part of some unspeakable evil? (No, I'm not paranoid, I just like mysteries and thought that punching this up with that kind of thing might keep you reading.  I know I'd fall asleep without it.) OK, so let's check out those 3 procedures and see what they reveal when I search for "Hekaton": sp_createstats: -- filter out local temp tables, Hekaton tables, and tables for which current user has no permissions -- Note that OBJECTPROPERTY returns NULL on type="IT" tables, thus we only call it on type='U' tables   OK, that's interesting, let's go looking down a little further: ((@table_type<>'U') or (0 = OBJECTPROPERTY(@table_id, 'TableIsInMemory'))) and -- Hekaton table   Wellllll, that tells us a few new things: There's such a thing as Hekaton tables (UPDATE: I'm not the only one to have found them!) They are not standard user tables and probably not in memory UPDATE: I misinterpreted this because I didn't read all the code when I wrote this blog post. The OBJECTPROPERTY function has an undocumented TableIsInMemory option Let's check out sp_recompile: -- (3) Must not be a Hekaton procedure.   And once again go a little further: if (ObjectProperty(@objid, 'IsExecuted') <> 0 AND ObjectProperty(@objid, 'IsInlineFunction') = 0 AND ObjectProperty(@objid, 'IsView') = 0 AND -- Hekaton procedure cannot be recompiled -- Make them go through schema version bumping branch, which will fail ObjectProperty(@objid, 'ExecIsCompiledProc') = 0)   And now we learn that hekaton procedures also exist, they can't be recompiled, there's a "schema version bumping branch" somewhere, and OBJECTPROPERTY has another undocumented option, ExecIsCompiledProc.  (If you experiment with this you'll find this option returns null, I think it only works when called from a system object.) This is neat! Sadly sp_updatestats doesn't reveal anything new, the comments about hekaton are the same as sp_createstats.  But we've ALSO discovered undocumented features for the OBJECTPROPERTY function, which we can now search for: SELECT name, object_definition(OBJECT_ID) FROM sys.all_objects WHERE object_definition(OBJECT_ID) LIKE '%OBJECTPROPERTY(%'   I'll leave that to you as more homework.  I should add that searching the system procedures was recommended long ago by the late, great Ken Henderson, in his Guru's Guide books, as a great way to find undocumented features.  That seems to be really good advice! Now if you're a programmer/hacker, you've probably been drooling over the last 5 entries for hekaton (in green), because these are the names of source code files for SQL Server!  Does this mean we can access the source code for SQL Server?  As The Oracle suggested to Neo, can we return to The Source??? Actually, no. Well, maybe a little bit.  While you won't get the actual source code from the compiled DLL and EXE files, you'll get references to source files, debugging symbols, variables and module names, error messages, and even the startup flags for SQL Server.  And if you search for "DBCC" or "CHECKDB" you'll find a really nice section listing all the DBCC commands, including the undocumented ones.  Granted those are pretty easy to find online, but you may be surprised what those web sites DIDN'T tell you! (And neither will I, go look for yourself!)  And as we saw earlier, you'll also find execution plan elements, query processing rules, and who knows what else.  It's also instructive to see how Microsoft organizes their source directories, how various components (storage engine, query processor, Full Text, AlwaysOn/HADR) are split into smaller modules. There are over 2000 source file references, go do some exploring! So what did we learn?  We can pull strings out of executable files, search them for known items, browse them for unknown items, and use the results to examine internal code to learn even more things about SQL Server.  We've even learned how to use command-line utilities!  We are now 1337 h4X0rz!  (Not really.  I hate that leetspeak crap.) Although, I must confess I might've gone too far with the "conspiracy" part of this post.  I apologize for that, it's just my overactive imagination.  There's really no hidden agenda or conspiracy regarding SQL Server internals.  It's not The Matrix.  It's not like you'd find anything like that in there: Attach Matrix Database DM_MATRIX_COMM_PIPELINES MATRIXXACTPARTICIPANTS dm_matrix_agents   Alright, enough of this paranoid ranting!  Microsoft are not really evil!  It's not like they're The Borg from Star Trek: ALTER FEDERATION DROP ALTER FEDERATION SPLIT DROP FEDERATION   #tsql2sday

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  • Using the “Settings.settings” functionalities in VB.NET can be tricky…

    - by Vincent Grondin
    Sometime you’re searching for something forever and when you find it, you realize it was right under your nose.  Maybe you were distracted by other things around… or maybe that thing right under your nose was so well hidden that it deserves a blog post…   That happened to me a few days ago while using the “Settings.settings” functionalities in my VB.NET application…  I thought it was a cool feature and I decided to use it…  So there I am adding new settings with “USER” scope and StringCollection as the data type, testing my application and everything works perfectly fine...  That was before I decided to modify the “Value” of one of my settings…  After changing the value of one of my settings, I start my application again and, to my surprise, my new values aren’t showing!  Hmmm… That’s odd…  My setting was a pretty long list of strings so I was rather angry at myself for not saving my work after I was done…  So I open up the Settings.setting in the designer and click the ellipsis symbol to enter my string collection again, but to my great pleasure (and disbelief) my strings are there!!!  Alright, you rock VB.NET!  You’ve just save me a bunch of typing time and I’m thinking it’s just a simple Visual Studio glitch…  I hit “Save” then “Save All” (just in case) and finally I rebuild everything and fire up my app once again.  Huh?  Where are my darn strings????????  Ok there’s a bug there…  I open up the app.config and my new strings are there!!!  Alright, let’s recap…  My new strings are in the app.config, they show correctly in the Settings.settings designer UI but they aren’t showing at runtime…  Hmmmm?  Let’s try something else…  Let’s start the application but outside Visual Studio this time… I fire up the exe and BAM!  My strings where there!  I “alt-tab” and hit “F5” and BOOM, no strings!  So it’s a bug in the Visual Studio environment… or could it be a FEATURE?  I must admit that I’m a little confused over what’s a bug and what’s a feature in Visual Studio… lol!   Finally I found out there’s a “cache” for your Visual Studio located here:  C:\Users\<your username>\AppData\Local\Microsoft\<your app name and a very weird temp ID>\<your app version>\user.config When using the “Settings.settings” with a setting of scope “user”, this file is out of sync with your app.config until you manually decide to update it… The button is right there… under your nose… at the top left corner of your screen in the settings designer…  See the big “Synchronize” button there?  Yep…  Now that’s user friendly isn’t it?  Oh, and wait until you see what it does when you click it…  It prompts you and basically says:  “Would you like your settings to start working inside Visual Studio now that you found out that I exist?” and of course the right answer is yes… or rather “OK”…  Unfortunately, you have to do this every time you edit a value… On the other hand, adding and removing settings seem to work flawlessly without having to click this magical button… go figure!  Oh and I almost forgot… this great “feature” is only available for VB.NET…  A project in C# using Settings.settings will work perfectly EVEN when editing values… Here’s a screenshot that shows this important button: Button Using other data types appears to work perfectly well…   Maybe it’s simply related to the StringCollection data type?  If you are a VB.NET programmer, you should pay attention to this when you plan on using the settings functionalities and your scope is “user” and your data type is StringCollection… Happy coding all!

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  • Calculating probability that a string has been randomized? - Python

    - by RadiantHex
    Hi folks, this is correlated to a question I asked earlier (question) I have a list of manually created strings such as: lucy87 gordan_king fancy_unicorn77 joplucky_kanga90 base_belong_to_narwhals and a list of randomized strings: johnkdf pancake90kgjd fancy_jagookfk manhattanljg What gives away that the last set of strings are randomized is that sequences such as 'kjg', 'jgf', 'lkd', ... . Any clever way I could separate strings that contain these apparently randomized strings from the crowd? I guess that this plays a lot on the fact that certain characters are more likely to be placed next to others (e.g. 'co', 'ka', 'ja', ...). Any ideas on this one? Kylotan mentioned Reverend, but I am not sure if it can be used fr such purpose. Help would be much appreciated!

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  • C# String Resource Values as Enum String Part values?

    - by JL
    Using VS2010 and .net V4.0 I would like to achieve the following: I already have 2 resource files in my project for 2 languages - English and Czech. I must say Resource Management in .net is excellent, I am suprised even to get code completion when implementing a String for example: string desc = Strings.ResourceManagerDesc This gets the string associated with the current culture of the thread. Now I am trying to create an Enum that can have the String portion of the Enum interpreted from the Strings resources. In the following way (This code DOES NOT WORK): public enum DownloadStatus { 1 = Strings.DownloadState_Complete, 2 = Strings.DownloadState_Failed, 3 = Strings.DownloadState_InProgress } This is a made up example, but you can see the point here. Since the above code won't work, is there a best practice way to achieve what I want?

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  • is there a way to use cin.getline() without having to define a char array size before hand?

    - by zebraman
    Basically my task is having to sort a bunch of strings of variable length ignoring case. I understand there is a function strcasecmp() that compares cstrings, but doesn't work on strings. Right now I'm using getline() for strings so I can just read in the strings one line at a time. I add these to a vector of strings, then convert to cstrings for each call of strcasecmp(). Instead of having to convert each string to a cstring before comparing with strcasecmp(), I was wondering if there was a way I could use cin.getline() for cstrings without having a predefined char array size. Or, would the best solution be to just read in string, convert to cstring, store in vector, then sort?

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  • Memcache key generation strategy

    - by Maxim Veksler
    Given function f1 which receives n String arguments, would be considered better random key generation strategy for memcache for the scenario described below ? Our Memcache client does internal md5sum hashing on the keys it gets public class MemcacheClient { public Object get(String key) { String md5 = Md5sum.md5(key) // Talk to memcached to get the Serialization... return memcached(md5); } } First option public static String f1(String s1, String s2, String s3, String s4) { String key = s1 + s2 + s3 + s4; return get(key); } Second option /** * Calculate hash from Strings * * @param objects vararg list of String's * * @return calculated md5sum hash */ public static String stringHash(Object... strings) { if(strings == null) throw new NullPointerException("D'oh! Can't calculate hash for null"); MD5 md5sum = new MD5(); // if(prevHash != null) // md5sum.Update(prevHash); for(int i = 0; i < strings.length; i++) { if(strings[i] != null) { md5sum.Update("_" + strings[i] + "_"); // Convert to String... } else { // If object is null, allow minimum entropy by hashing it's position md5sum.Update("_" + i + "_"); } } return md5sum.asHex(); } public static String f1(String s1, String s2, String s3, String s4) { String key = stringHash(s1, s2, s3, s4); return get(key); } Note that the possible problem with the second option is that we are doing second md5sum (in the memcache client) on an already md5sum'ed digest result. Thanks for reading, Maxim.

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  • How can I make nested string splits?

    - by Statement
    I have what seemed at first to be a trivial problem but turned out to become something I can't figure out how to easily solve. I need to be able to store lists of items in a string. Then those items in turn can be a list, or some other value that may contain my separator character. I have two different methods that unpack the two different cases but I realized I need to encode the contained value from any separator characters used with string.Split. To illustrate the problem: string[] nested = { "mary;john;carl", "dog;cat;fish", "plainValue" } string list = string.Join(";", nested); string[] unnested = list.Split(';'); // EEK! returns 7 items, expected 3! This would produce a list "mary;john;carl;dog;cat;fish;plainValue", a value I can't split to get the three original nested strings from. Indeed, instead of the three original strings, I'd get 7 strings on split and this approach thus doesn't work at all. What I want is to allow the values in my string to be encoded so I can unpack/split the contents just the way before I packed/join them. I assume I might need to go away from string.Split and string.Join and that is perfectly fine. I might just have overlooked some useful class or method. How can I allow any string values to be packed / unpacked into lists? I prefer neat, simple solutions over bulky if possible. For the curious mind, I am making extensions for PlayerPrefs in Unity3D, and I can only work with ints, floats and strings. Thus I chose strings to be my data carrier. This is why I am making this nested list of strings.

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  • C++ string sort like a human being?

    - by Walter Nissen
    I would like to sort alphanumeric strings the way a human being would sort them. I.e., "A2" comes before "A10", and "a" certainly comes before "Z"! Is there any way to do with without writing a mini-parser? Ideally it would also put "A1B1" before "A1B10". I see the question "Natural (human alpha-numeric) sort in Microsoft SQL 2005" with a possible answer, but it uses various library functions, as does "Sorting Strings for Humans with IComparer". Below is a test case that currently fails: #include <set> #include <iterator> #include <iostream> #include <vector> #include <cassert> template <typename T> struct LexicographicSort { inline bool operator() (const T& lhs, const T& rhs) const{ std::ostringstream s1,s2; s1 << toLower(lhs); s2 << toLower(rhs); bool less = s1.str() < s2.str(); std::cout<<s1.str()<<" "<<s2.str()<<" "<<less<<"\n"; return less; } inline std::string toLower(const std::string& str) const { std::string newString(""); for (std::string::const_iterator charIt = str.begin(); charIt!=str.end();++charIt) { newString.push_back(std::tolower(*charIt)); } return newString; } }; int main(void) { const std::string reference[5] = {"ab","B","c1","c2","c10"}; std::vector<std::string> referenceStrings(&(reference[0]), &(reference[5])); //Insert in reverse order so we know they get sorted std::set<std::string,LexicographicSort<std::string> > strings(referenceStrings.rbegin(), referenceStrings.rend()); std::cout<<"Items:\n"; std::copy(strings.begin(), strings.end(), std::ostream_iterator<std::string>(std::cout, "\n")); std::vector<std::string> sortedStrings(strings.begin(), strings.end()); assert(sortedStrings == referenceStrings); }

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  • What's wrong in this C program..? [closed]

    - by AGeek
    struct bucket { int nStrings; //No. of Strings in a Bucket. char strings[MAXSTRINGS][MAXWORDLENGTH]; // A bucket row can contain maximum 9 strings of max string length 10. };//buck[TOTBUCKETS]; void lexSorting(char array[][10], int lenArray, int symb) //symb - symbol, sorting based on character symbols. { int i, j; int bucketNo; int tBuckNStrings; bucket buck[TOTBUCKETS]; for(i=0; i<lenArray; i++) { bucketNo = array[i][symb] - 'a'; // Find Bucket No. in which the string is to be placed. tBuckNStrings = buck[bucketNo].nStrings; // temp variable for storing nStrings var in bucket structure. strcpy(buck[bucketNo].strings[tBuckNStrings],array[i]); // Store the string in its bucket. buck[bucketNo].nStrings = ++tBuckNStrings; //Increment the nStrings value of the bucket. } // lexSorting(array, lenArray, ++symb); printf("****** %d ******\n", symb); for(i=0; i<TOTBUCKETS; i++) { printf("%c = ", i+'a'); for(j=0; j<buck[i].nStrings; j++) printf("%s ",buck[i].strings[j]); printf("\n"); } } int main() { char array[][10] = {"able","aback","a","abet","acid","yawn","yard","yarn","year","yoke"}; int lenArray = 10; int i; printf("Strings: "); for(i=0; i<lenArray; i++) printf("%s ",array[i]); printf("\n"); lexSorting(array, lenArray, 0); } Well here is the complete code, that I am trying. since its been a long time since i have touched upon C programming, so somewhere i am making mistake in structure declaration. The problem goes here:- 1) I have declared a structure above and its object as array(buck[]). 2) Now when I declare this object array along with the structure, it works fine.. I have commented this thing right now. 3) But when I declare this object array inside the function.. because ultimately i have to declare inside function( as i need to build a recursive program, where objects will be created in very recursive call) then the program is throwing segmentation fault. Expected Output > [others@centos htdocs]$ ./a.out > Strings: able aback a abet acid yawn > yard yarn year yoke > ****** 0 ****** > a = able aback a abet acid > b = > c > . > . > y = yawn yard yarnyear yoke > z = Actual Output [others@centos htdocs]$ ./a.out Strings: able aback a abet acid yawn yard yarn year yoke Segmentation fault I have no idea, what difference I made in this. Kindly help. Thanks.

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  • What's the difference between find and findstr commands in Windows?

    - by Prashant Bhate
    In Windows, what are the differences between find and findstr commands? Both seems to search text in files: find c:\>find /? Searches for a text string in a file or files. FIND [/V] [/C] [/N] [/I] [/OFF[LINE]] "string" [[drive:][path]filename[ ...]] /V Displays all lines NOT containing the specified string. /C Displays only the count of lines containing the string. /N Displays line numbers with the displayed lines. /I Ignores the case of characters when searching for the string. /OFF[LINE] Do not skip files with offline attribute set. "string" Specifies the text string to find. [drive:][path]filename Specifies a file or files to search. If a path is not specified, FIND searches the text typed at the prompt or piped from another command. findstr c:\>findstr /? Searches for strings in files. FINDSTR [/B] [/E] [/L] [/R] [/S] [/I] [/X] [/V] [/N] [/M] [/O] [/P] [/F:file] [/C:string] [/G:file] [/D:dir list] [/A:color attributes] [/OFF[LINE]] strings [[drive:][path]filename[ ...]] /B Matches pattern if at the beginning of a line. /E Matches pattern if at the end of a line. /L Uses search strings literally. /R Uses search strings as regular expressions. /S Searches for matching files in the current directory and all subdirectories. /I Specifies that the search is not to be case-sensitive. /X Prints lines that match exactly. /V Prints only lines that do not contain a match. /N Prints the line number before each line that matches. /M Prints only the filename if a file contains a match. /O Prints character offset before each matching line. /P Skip files with non-printable characters. /OFF[LINE] Do not skip files with offline attribute set. /A:attr Specifies color attribute with two hex digits. See "color /?" /F:file Reads file list from the specified file(/ stands for console). /C:string Uses specified string as a literal search string. /G:file Gets search strings from the specified file(/ stands for console). /D:dir Search a semicolon delimited list of directories strings Text to be searched for. [drive:][path]filename Specifies a file or files to search. Use spaces to separate multiple search strings unless the argument is prefixed with /C. For example, 'FINDSTR "hello there" x.y' searches for "hello" or "there" in file x.y. 'FINDSTR /C:"hello there" x.y' searches for "hello there" in file x.y. Regular expression quick reference: . Wildcard: any character * Repeat: zero or more occurances of previous character or class ^ Line position: beginning of line $ Line position: end of line [class] Character class: any one character in set [^class] Inverse class: any one character not in set [x-y] Range: any characters within the specified range \x Escape: literal use of metacharacter x \<xyz Word position: beginning of word xyz\> Word position: end of word For full information on FINDSTR regular expressions refer to the online Command Reference.

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  • Compute the AES-encryption key given the plaintext and its ciphertext?

    - by Null Pointers etc.
    I'm tasked with creating database tables in Oracle which contain encrypted strings (i.e., the columns are RAW). The strings are encrypted by the application (using AES, 128-bit key) and stored in Oracle, then later retrieved from Oracle and decrypted (i.e., Oracle itself never sees the unencrypted strings). I've come across this one column that will be one of two strings. I'm worried that someone will notice and presumably figure out what those two values to figure out the AES key. For example, if someone sees that the column is either Ciphertext #1 or #2: Ciphertext #1: BF,4F,8B,FE, 60,D8,33,56, 1B,F2,35,72, 49,20,DE,C6. Ciphertext #2: BC,E8,54,BD, F4,B3,36,3B, DD,70,76,45, 29,28,50,07. and knows the corresponding Plaintexts: Plaintext #1 ("Detroit"): 44,00,65,00, 74,00,72,00, 6F,00,69,00, 74,00,00,00. Plaintext #2 ("Chicago"): 43,00,68,00, 69,00,63,00, 61,00,67,00, 6F,00,00,00. can he deduce that the encryption key is "Buffalo"? 42,00,75,00, 66,00,66,00, 61,00,6C,00, 6F,00,00,00. I'm thinking that there should be only one 128-bit key that could convert Plaintext #1 to Ciphertext #1. Does this mean I should go to a 192-bit or 256-bit key instead, or find some other solution? (As an aside, here are two other ciphertexts for the same plaintexts but with a different key.) Ciphertext #1 A ("Detroit"): E4,28,29,E3, 6E,C2,64,FA, A1,F4,F4,96, FC,18,4A,C5. Ciphertext #2 A ("Chicago"): EA,87,30,F0, AC,44,5D,ED, FD,EB,A8,79, 83,59,53,B7.

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  • Creating and maintaining Orchard translations

    - by Bertrand Le Roy
    Many volunteers have already stepped up to provide translations for Orchard. There are many challenges to overcome with translating such a project. Orchard is a very modular CMS, so the translation mechanism needs to account for the core as well as first and third party modules and themes. Another issue is that every new version of Orchard or of a module changes some localizable strings and adds new ones as others enter obsolescence. In order to address those problems, I've built a small Orchard module that automates some of the most complex tasks that maintaining a translation implies. In this post, I'll walk you through the operations I had to do to update the French translation for Orchard 1.0. In order to make sure you translate all the first party modules, I would recommend that you start from a full source code enlistment. The reason is that I'll show how you can extract the default en-US translation from any source code enlistment. That enables you to create a translation that is even more up-to-date than what is currently on the site. Alternatively, you could start by downloading the current en-US translation. If you decide to do so, just skip the relevant paragraphs. First, let's install the Orchard Translation Manager. I'm starting from a vanilla clone of the latest in the code repository. After you've setup the site, go into the dashboard and click on Gallery. Locate the Orchard Translation Manager in the list of modules and click "Install". Once the module is installed, you need to enable its one feature by going into Configuration/Features and clicking "Enable" next to Vandelay.TranslationManager. We're done with the setup that we need in order to start our translation work. We'll now switch to the command-line and to our favorite text editor. Open a command-line on the Orchard web site folder. I found the easiest way to do this is to do a SHIFT+right-click on the Orchard.Web folder in Windows Explorer and to click "Open command window here". Type bin\orchard to enter the Orchard command-line environment. If you do a "help commands" you should see four commands in the list that came from the module we just installed: extract default translation, install translation, package translation and sync translation. First, we're going to generate the default translation. Note that it is possible to generate that default translation for a specific list of modules and themes by using the /Extensions: switch, which should facilitate the translation of third party extensions, but in this tutorial we're going to generate it for the whole of the Orchard source code. extract default translation /Output:\temp .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } This should have created an Orchard.en-us.po.zip file in the temp directory. Extract that archive into an orchard.po folder under \temp. The next step depends on whether you have an existing translation that you want to update or not. If you do have an existing translation, just extract it into the same \temp\orchard.po directory. That should result in a file structure where you have the default en-US translation alongside your own. If you don't have an existing translation, just continue, the commands will be the same. We are now going to synchronize those translations (or generate the stub for a new one if you didn't start from an existing translation). sync translation /Input:\temp\orchard.po /Culture:fr-FR After this command (where you should of course substitute fr-FR with the culture you're working on), we now have updated files that contain a few useful flags. Open each of the .po files under the culture you are working on (there should be around 36) with your favorite text editor. For all the strings that are still valid in the latest version, nothing changes and you don't need to do anything. For all the strings that disappeared from the default culture, the old translation will still be there but they will be prefixed with the following comment: # Obsolete translation Conveniently, all the obsolete strings will be grouped at the end of the file. You can select all those and delete them. For all the new strings, you will see the following comment: # Untranslated string This is where the hard work begins. You'll need to translate each of those new strings by entering the translation between the quotes in: msgstr "" Don't introduce hard carriage returns in the strings, just stay on one line (your text editor should do some reasonable wrapping so this shouldn't be a big deal). Once you're done with a file, save it. Make sure, and this is very important, that your text editor is saving using the UTF-8 encoding. In Notepad, that setting can be found in the file saving dialog by doing a "Save As" rather than a plain "Save": When all the po files have been edited, you are ready to package the translation for submission (a.k.a. sending e-mail to the localization mailing list). package translation /Culture:fr-FR /Input:\temp\orchard.po /Output:\temp You should now see a Orchard.fr-FR.po.zip file in temp that is ready to be submitted. That is, once you've tested it, which can be done by deploying it into the site: install translation \temp\orchard.fr-fr.po.zip Once this is done you can go into the dashboard under Configuration/Settings and click on "Add or remove supported cultures for the site". Choose your culture and click "Add". You can go back to settings and set the default culture. Save. You may now take a tour of the application and verify that everything works as expected: And that's it really. Creating a translation for Orchard is a matter of a few hours. If you don't see a translation for your culture, please consider creating it.

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  • is there a downside to putting N in front of strings in scripts? Is it considered a "best practice"?

    - by jcollum
    Let's say I have a table that has a varchar field. If I do an insert like this: INSERT MyTable SELECT N'the string goes here' Is there any fundamental difference between that and: INSERT MyTable SELECT 'the string goes here' My understanding was that you'd only have a problem if the string contained a Unicode character and the target column wasn't unicode. Other than that, SQL deals with it just fine and converts the string with the N'' into a varchar field (basically ignores the N). I was under the impression that N in front of strings was a good practice, but I'm unable to find any discussion of it that I'd consider definitive. Title may need improvement, feel free.

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  • Write a GreaseMonkey script that reacts to domain strings (for I18N, e.g. cn,en,fr,etc.)

    - by Shizhidi
    Hello. Suppose there is a website that supports multiple languages: cn.mydomain.com or mydomain.com/cn or mydomain.cn en.mydomain.com or mydomain.com/en or mydomain.com fr.mydomain.com or mydomain.com/fr or mydomain.fr I want to write a GreaseMonkey script that has variables assigned different strings/values according to the address the user is loading the page from. How do you do that? Thanks EDIT: I realize I can just use JavaScript to get the address. Does GreaseMonkey itself support this kind of function?

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  • New features of C# 4.0

    This article covers New features of C# 4.0. Article has been divided into below sections. Introduction. Dynamic Lookup. Named and Optional Arguments. Features for COM interop. Variance. Relationship with Visual Basic. Resources. Other interested readings… 22 New Features of Visual Studio 2008 for .NET Professionals 50 New Features of SQL Server 2008 IIS 7.0 New features Introduction It is now close to a year since Microsoft Visual C# 3.0 shipped as part of Visual Studio 2008. In the VS Managed Languages team we are hard at work on creating the next version of the language (with the unsurprising working title of C# 4.0), and this document is a first public description of the planned language features as we currently see them. Please be advised that all this is in early stages of production and is subject to change. Part of the reason for sharing our plans in public so early is precisely to get the kind of feedback that will cause us to improve the final product before it rolls out. Simultaneously with the publication of this whitepaper, a first public CTP (community technology preview) of Visual Studio 2010 is going out as a Virtual PC image for everyone to try. Please use it to play and experiment with the features, and let us know of any thoughts you have. We ask for your understanding and patience working with very early bits, where especially new or newly implemented features do not have the quality or stability of a final product. The aim of the CTP is not to give you a productive work environment but to give you the best possible impression of what we are working on for the next release. The CTP contains a number of walkthroughs, some of which highlight the new language features of C# 4.0. Those are excellent for getting a hands-on guided tour through the details of some common scenarios for the features. You may consider this whitepaper a companion document to these walkthroughs, complementing them with a focus on the overall language features and how they work, as opposed to the specifics of the concrete scenarios. C# 4.0 The major theme for C# 4.0 is dynamic programming. Increasingly, objects are “dynamic” in the sense that their structure and behavior is not captured by a static type, or at least not one that the compiler knows about when compiling your program. Some examples include a. objects from dynamic programming languages, such as Python or Ruby b. COM objects accessed through IDispatch c. ordinary .NET types accessed through reflection d. objects with changing structure, such as HTML DOM objects While C# remains a statically typed language, we aim to vastly improve the interaction with such objects. A secondary theme is co-evolution with Visual Basic. Going forward we will aim to maintain the individual character of each language, but at the same time important new features should be introduced in both languages at the same time. They should be differentiated more by style and feel than by feature set. The new features in C# 4.0 fall into four groups: Dynamic lookup Dynamic lookup allows you to write method, operator and indexer calls, property and field accesses, and even object invocations which bypass the C# static type checking and instead gets resolved at runtime. Named and optional parameters Parameters in C# can now be specified as optional by providing a default value for them in a member declaration. When the member is invoked, optional arguments can be omitted. Furthermore, any argument can be passed by parameter name instead of position. COM specific interop features Dynamic lookup as well as named and optional parameters both help making programming against COM less painful than today. On top of that, however, we are adding a number of other small features that further improve the interop experience. Variance It used to be that an IEnumerable<string> wasn’t an IEnumerable<object>. Now it is – C# embraces type safe “co-and contravariance” and common BCL types are updated to take advantage of that. Dynamic Lookup Dynamic lookup allows you a unified approach to invoking things dynamically. With dynamic lookup, when you have an object in your hand you do not need to worry about whether it comes from COM, IronPython, the HTML DOM or reflection; you just apply operations to it and leave it to the runtime to figure out what exactly those operations mean for that particular object. This affords you enormous flexibility, and can greatly simplify your code, but it does come with a significant drawback: Static typing is not maintained for these operations. A dynamic object is assumed at compile time to support any operation, and only at runtime will you get an error if it wasn’t so. Oftentimes this will be no loss, because the object wouldn’t have a static type anyway, in other cases it is a tradeoff between brevity and safety. In order to facilitate this tradeoff, it is a design goal of C# to allow you to opt in or opt out of dynamic behavior on every single call. The dynamic type C# 4.0 introduces a new static type called dynamic. When you have an object of type dynamic you can “do things to it” that are resolved only at runtime: dynamic d = GetDynamicObject(…); d.M(7); The C# compiler allows you to call a method with any name and any arguments on d because it is of type dynamic. At runtime the actual object that d refers to will be examined to determine what it means to “call M with an int” on it. The type dynamic can be thought of as a special version of the type object, which signals that the object can be used dynamically. It is easy to opt in or out of dynamic behavior: any object can be implicitly converted to dynamic, “suspending belief” until runtime. Conversely, there is an “assignment conversion” from dynamic to any other type, which allows implicit conversion in assignment-like constructs: dynamic d = 7; // implicit conversion int i = d; // assignment conversion Dynamic operations Not only method calls, but also field and property accesses, indexer and operator calls and even delegate invocations can be dispatched dynamically: dynamic d = GetDynamicObject(…); d.M(7); // calling methods d.f = d.P; // getting and settings fields and properties d[“one”] = d[“two”]; // getting and setting thorugh indexers int i = d + 3; // calling operators string s = d(5,7); // invoking as a delegate The role of the C# compiler here is simply to package up the necessary information about “what is being done to d”, so that the runtime can pick it up and determine what the exact meaning of it is given an actual object d. Think of it as deferring part of the compiler’s job to runtime. The result of any dynamic operation is itself of type dynamic. Runtime lookup At runtime a dynamic operation is dispatched according to the nature of its target object d: COM objects If d is a COM object, the operation is dispatched dynamically through COM IDispatch. This allows calling to COM types that don’t have a Primary Interop Assembly (PIA), and relying on COM features that don’t have a counterpart in C#, such as indexed properties and default properties. Dynamic objects If d implements the interface IDynamicObject d itself is asked to perform the operation. Thus by implementing IDynamicObject a type can completely redefine the meaning of dynamic operations. This is used intensively by dynamic languages such as IronPython and IronRuby to implement their own dynamic object models. It will also be used by APIs, e.g. by the HTML DOM to allow direct access to the object’s properties using property syntax. Plain objects Otherwise d is a standard .NET object, and the operation will be dispatched using reflection on its type and a C# “runtime binder” which implements C#’s lookup and overload resolution semantics at runtime. This is essentially a part of the C# compiler running as a runtime component to “finish the work” on dynamic operations that was deferred by the static compiler. Example Assume the following code: dynamic d1 = new Foo(); dynamic d2 = new Bar(); string s; d1.M(s, d2, 3, null); Because the receiver of the call to M is dynamic, the C# compiler does not try to resolve the meaning of the call. Instead it stashes away information for the runtime about the call. This information (often referred to as the “payload”) is essentially equivalent to: “Perform an instance method call of M with the following arguments: 1. a string 2. a dynamic 3. a literal int 3 4. a literal object null” At runtime, assume that the actual type Foo of d1 is not a COM type and does not implement IDynamicObject. In this case the C# runtime binder picks up to finish the overload resolution job based on runtime type information, proceeding as follows: 1. Reflection is used to obtain the actual runtime types of the two objects, d1 and d2, that did not have a static type (or rather had the static type dynamic). The result is Foo for d1 and Bar for d2. 2. Method lookup and overload resolution is performed on the type Foo with the call M(string,Bar,3,null) using ordinary C# semantics. 3. If the method is found it is invoked; otherwise a runtime exception is thrown. Overload resolution with dynamic arguments Even if the receiver of a method call is of a static type, overload resolution can still happen at runtime. This can happen if one or more of the arguments have the type dynamic: Foo foo = new Foo(); dynamic d = new Bar(); var result = foo.M(d); The C# runtime binder will choose between the statically known overloads of M on Foo, based on the runtime type of d, namely Bar. The result is again of type dynamic. The Dynamic Language Runtime An important component in the underlying implementation of dynamic lookup is the Dynamic Language Runtime (DLR), which is a new API in .NET 4.0. The DLR provides most of the infrastructure behind not only C# dynamic lookup but also the implementation of several dynamic programming languages on .NET, such as IronPython and IronRuby. Through this common infrastructure a high degree of interoperability is ensured, but just as importantly the DLR provides excellent caching mechanisms which serve to greatly enhance the efficiency of runtime dispatch. To the user of dynamic lookup in C#, the DLR is invisible except for the improved efficiency. However, if you want to implement your own dynamically dispatched objects, the IDynamicObject interface allows you to interoperate with the DLR and plug in your own behavior. This is a rather advanced task, which requires you to understand a good deal more about the inner workings of the DLR. For API writers, however, it can definitely be worth the trouble in order to vastly improve the usability of e.g. a library representing an inherently dynamic domain. Open issues There are a few limitations and things that might work differently than you would expect. · The DLR allows objects to be created from objects that represent classes. However, the current implementation of C# doesn’t have syntax to support this. · Dynamic lookup will not be able to find extension methods. Whether extension methods apply or not depends on the static context of the call (i.e. which using clauses occur), and this context information is not currently kept as part of the payload. · Anonymous functions (i.e. lambda expressions) cannot appear as arguments to a dynamic method call. The compiler cannot bind (i.e. “understand”) an anonymous function without knowing what type it is converted to. One consequence of these limitations is that you cannot easily use LINQ queries over dynamic objects: dynamic collection = …; var result = collection.Select(e => e + 5); If the Select method is an extension method, dynamic lookup will not find it. Even if it is an instance method, the above does not compile, because a lambda expression cannot be passed as an argument to a dynamic operation. There are no plans to address these limitations in C# 4.0. Named and Optional Arguments Named and optional parameters are really two distinct features, but are often useful together. Optional parameters allow you to omit arguments to member invocations, whereas named arguments is a way to provide an argument using the name of the corresponding parameter instead of relying on its position in the parameter list. Some APIs, most notably COM interfaces such as the Office automation APIs, are written specifically with named and optional parameters in mind. Up until now it has been very painful to call into these APIs from C#, with sometimes as many as thirty arguments having to be explicitly passed, most of which have reasonable default values and could be omitted. Even in APIs for .NET however you sometimes find yourself compelled to write many overloads of a method with different combinations of parameters, in order to provide maximum usability to the callers. Optional parameters are a useful alternative for these situations. Optional parameters A parameter is declared optional simply by providing a default value for it: public void M(int x, int y = 5, int z = 7); Here y and z are optional parameters and can be omitted in calls: M(1, 2, 3); // ordinary call of M M(1, 2); // omitting z – equivalent to M(1, 2, 7) M(1); // omitting both y and z – equivalent to M(1, 5, 7) Named and optional arguments C# 4.0 does not permit you to omit arguments between commas as in M(1,,3). This could lead to highly unreadable comma-counting code. Instead any argument can be passed by name. Thus if you want to omit only y from a call of M you can write: M(1, z: 3); // passing z by name or M(x: 1, z: 3); // passing both x and z by name or even M(z: 3, x: 1); // reversing the order of arguments All forms are equivalent, except that arguments are always evaluated in the order they appear, so in the last example the 3 is evaluated before the 1. Optional and named arguments can be used not only with methods but also with indexers and constructors. Overload resolution Named and optional arguments affect overload resolution, but the changes are relatively simple: A signature is applicable if all its parameters are either optional or have exactly one corresponding argument (by name or position) in the call which is convertible to the parameter type. Betterness rules on conversions are only applied for arguments that are explicitly given – omitted optional arguments are ignored for betterness purposes. If two signatures are equally good, one that does not omit optional parameters is preferred. M(string s, int i = 1); M(object o); M(int i, string s = “Hello”); M(int i); M(5); Given these overloads, we can see the working of the rules above. M(string,int) is not applicable because 5 doesn’t convert to string. M(int,string) is applicable because its second parameter is optional, and so, obviously are M(object) and M(int). M(int,string) and M(int) are both better than M(object) because the conversion from 5 to int is better than the conversion from 5 to object. Finally M(int) is better than M(int,string) because no optional arguments are omitted. Thus the method that gets called is M(int). Features for COM interop Dynamic lookup as well as named and optional parameters greatly improve the experience of interoperating with COM APIs such as the Office Automation APIs. In order to remove even more of the speed bumps, a couple of small COM-specific features are also added to C# 4.0. Dynamic import Many COM methods accept and return variant types, which are represented in the PIAs as object. In the vast majority of cases, a programmer calling these methods already knows the static type of a returned object from context, but explicitly has to perform a cast on the returned value to make use of that knowledge. These casts are so common that they constitute a major nuisance. In order to facilitate a smoother experience, you can now choose to import these COM APIs in such a way that variants are instead represented using the type dynamic. In other words, from your point of view, COM signatures now have occurrences of dynamic instead of object in them. This means that you can easily access members directly off a returned object, or you can assign it to a strongly typed local variable without having to cast. To illustrate, you can now say excel.Cells[1, 1].Value = "Hello"; instead of ((Excel.Range)excel.Cells[1, 1]).Value2 = "Hello"; and Excel.Range range = excel.Cells[1, 1]; instead of Excel.Range range = (Excel.Range)excel.Cells[1, 1]; Compiling without PIAs Primary Interop Assemblies are large .NET assemblies generated from COM interfaces to facilitate strongly typed interoperability. They provide great support at design time, where your experience of the interop is as good as if the types where really defined in .NET. However, at runtime these large assemblies can easily bloat your program, and also cause versioning issues because they are distributed independently of your application. The no-PIA feature allows you to continue to use PIAs at design time without having them around at runtime. Instead, the C# compiler will bake the small part of the PIA that a program actually uses directly into its assembly. At runtime the PIA does not have to be loaded. Omitting ref Because of a different programming model, many COM APIs contain a lot of reference parameters. Contrary to refs in C#, these are typically not meant to mutate a passed-in argument for the subsequent benefit of the caller, but are simply another way of passing value parameters. It therefore seems unreasonable that a C# programmer should have to create temporary variables for all such ref parameters and pass these by reference. Instead, specifically for COM methods, the C# compiler will allow you to pass arguments by value to such a method, and will automatically generate temporary variables to hold the passed-in values, subsequently discarding these when the call returns. In this way the caller sees value semantics, and will not experience any side effects, but the called method still gets a reference. Open issues A few COM interface features still are not surfaced in C#. Most notably these include indexed properties and default properties. As mentioned above these will be respected if you access COM dynamically, but statically typed C# code will still not recognize them. There are currently no plans to address these remaining speed bumps in C# 4.0. Variance An aspect of generics that often comes across as surprising is that the following is illegal: IList<string> strings = new List<string>(); IList<object> objects = strings; The second assignment is disallowed because strings does not have the same element type as objects. There is a perfectly good reason for this. If it were allowed you could write: objects[0] = 5; string s = strings[0]; Allowing an int to be inserted into a list of strings and subsequently extracted as a string. This would be a breach of type safety. However, there are certain interfaces where the above cannot occur, notably where there is no way to insert an object into the collection. Such an interface is IEnumerable<T>. If instead you say: IEnumerable<object> objects = strings; There is no way we can put the wrong kind of thing into strings through objects, because objects doesn’t have a method that takes an element in. Variance is about allowing assignments such as this in cases where it is safe. The result is that a lot of situations that were previously surprising now just work. Covariance In .NET 4.0 the IEnumerable<T> interface will be declared in the following way: public interface IEnumerable<out T> : IEnumerable { IEnumerator<T> GetEnumerator(); } public interface IEnumerator<out T> : IEnumerator { bool MoveNext(); T Current { get; } } The “out” in these declarations signifies that the T can only occur in output position in the interface – the compiler will complain otherwise. In return for this restriction, the interface becomes “covariant” in T, which means that an IEnumerable<A> is considered an IEnumerable<B> if A has a reference conversion to B. As a result, any sequence of strings is also e.g. a sequence of objects. This is useful e.g. in many LINQ methods. Using the declarations above: var result = strings.Union(objects); // succeeds with an IEnumerable<object> This would previously have been disallowed, and you would have had to to some cumbersome wrapping to get the two sequences to have the same element type. Contravariance Type parameters can also have an “in” modifier, restricting them to occur only in input positions. An example is IComparer<T>: public interface IComparer<in T> { public int Compare(T left, T right); } The somewhat baffling result is that an IComparer<object> can in fact be considered an IComparer<string>! It makes sense when you think about it: If a comparer can compare any two objects, it can certainly also compare two strings. This property is referred to as contravariance. A generic type can have both in and out modifiers on its type parameters, as is the case with the Func<…> delegate types: public delegate TResult Func<in TArg, out TResult>(TArg arg); Obviously the argument only ever comes in, and the result only ever comes out. Therefore a Func<object,string> can in fact be used as a Func<string,object>. Limitations Variant type parameters can only be declared on interfaces and delegate types, due to a restriction in the CLR. Variance only applies when there is a reference conversion between the type arguments. For instance, an IEnumerable<int> is not an IEnumerable<object> because the conversion from int to object is a boxing conversion, not a reference conversion. Also please note that the CTP does not contain the new versions of the .NET types mentioned above. In order to experiment with variance you have to declare your own variant interfaces and delegate types. COM Example Here is a larger Office automation example that shows many of the new C# features in action. using System; using System.Diagnostics; using System.Linq; using Excel = Microsoft.Office.Interop.Excel; using Word = Microsoft.Office.Interop.Word; class Program { static void Main(string[] args) { var excel = new Excel.Application(); excel.Visible = true; excel.Workbooks.Add(); // optional arguments omitted excel.Cells[1, 1].Value = "Process Name"; // no casts; Value dynamically excel.Cells[1, 2].Value = "Memory Usage"; // accessed var processes = Process.GetProcesses() .OrderByDescending(p =&gt; p.WorkingSet) .Take(10); int i = 2; foreach (var p in processes) { excel.Cells[i, 1].Value = p.ProcessName; // no casts excel.Cells[i, 2].Value = p.WorkingSet; // no casts i++; } Excel.Range range = excel.Cells[1, 1]; // no casts Excel.Chart chart = excel.ActiveWorkbook.Charts. Add(After: excel.ActiveSheet); // named and optional arguments chart.ChartWizard( Source: range.CurrentRegion, Title: "Memory Usage in " + Environment.MachineName); //named+optional chart.ChartStyle = 45; chart.CopyPicture(Excel.XlPictureAppearance.xlScreen, Excel.XlCopyPictureFormat.xlBitmap, Excel.XlPictureAppearance.xlScreen); var word = new Word.Application(); word.Visible = true; word.Documents.Add(); // optional arguments word.Selection.Paste(); } } The code is much more terse and readable than the C# 3.0 counterpart. Note especially how the Value property is accessed dynamically. This is actually an indexed property, i.e. a property that takes an argument; something which C# does not understand. However the argument is optional. Since the access is dynamic, it goes through the runtime COM binder which knows to substitute the default value and call the indexed property. Thus, dynamic COM allows you to avoid accesses to the puzzling Value2 property of Excel ranges. Relationship with Visual Basic A number of the features introduced to C# 4.0 already exist or will be introduced in some form or other in Visual Basic: · Late binding in VB is similar in many ways to dynamic lookup in C#, and can be expected to make more use of the DLR in the future, leading to further parity with C#. · Named and optional arguments have been part of Visual Basic for a long time, and the C# version of the feature is explicitly engineered with maximal VB interoperability in mind. · NoPIA and variance are both being introduced to VB and C# at the same time. VB in turn is adding a number of features that have hitherto been a mainstay of C#. As a result future versions of C# and VB will have much better feature parity, for the benefit of everyone. Resources All available resources concerning C# 4.0 can be accessed through the C# Dev Center. Specifically, this white paper and other resources can be found at the Code Gallery site. Enjoy! span.fullpost {display:none;}

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  • Good ol fashioned debugging

    - by Tim Dexter
    I have been helping out one of our new customers over the last day or two and I have even managed to get to the bottom of their problem FTW! They use BIEE and BIP and wanted to mount a BIP report in a dashboard page, so far so good, BIP does that! Just follow the instructions in the BIEE user guide. The wrinkle is that they want to enter some fixed instruction strings into the dashboard prompts to help the user. These are added as fixed values to the prompt as the default values so they appear first. Once the user makes a selection, the default strings disappear. Its a fair requirement but the BIP report chokes Now, the BIP report had been setup with the Autorun checkbox, unchecked. I expected the BIP report to wait for the Go button to be hit but it was trying to run immediately and failing. That was the first issue. You can not stop the BIP report from trying to run in a dashboard. Even if the Autorun is turned off, it seems that dashboard still makes the request to BIP to run the report. Rather than BIP refusing because its waiting for input it goes ahead anyway, I guess the mechanism does not check the autorun flag when the request is coming from the dashboard. It appears that between BIEE and BIP, they collectively ignore the autorun flag. A bug? might be, at least an enhancement request. With that in mind, how could we get BIP to not at least not fail? This fact was stumping me on the parameter error, if the autorun flag was being respected then why was BIP complaining about the parameter values it should not even be doing anything until the Go button is clicked. I now knew that the autorun flag was being ignored, it was a simple case of putting BIP into debug mode. I use the OC4J server on my laptop so debug msgs are routed through the dos box used to start the OC4J container. When I changed a value on the dashboard prompt I spotted some debug text rushing by that subsequently disappeared from the log once the operation was complete. Another bug? I needed to catch that text as it went by, using the print screen function with some software to grab multiple screens as the log appeared and then disappeared. The upshot is that when you change the dashboard prompt value, BIP validates the value against its own LOVs, if its not in the list then it throws the error. Because 'Fill this first' and 'Fill this second' ie fixed strings from the dashboard prompts, are not in the LOV lists and because the report is auto running as soon as the dashboard page is brought up, the report complains about invalid parameters. To get around this, I needed to get the strings into the LOVs. Easily done with a UNION clause: select 'Fill this first' from SH.Products Products UNION select Products."Prod Category" as "Prod Category" from SH.Products Products Now when BIP wants to validate the prompt value, the LOV query fires and finds the fixed string -> No Error. No data, but definitely no errors :0) If users do run with the fixed values, you can capture that in the template. If there is no data in the report, either the fixed values were used or the parameters selected resulted in no rows. You can capture this in the template and display something like. 'Either your parameter values resulted in no data or you have not changed the default values' Thats the upside, the downside is that if your users run the report in the BP UI they re going to see the fixed strings. You could alleviate that by having BIP display the fixed strings in top of its parameter drop boxes (just set them as the default value for the parameter.) But they will not disappear like they do in the dashboard prompts, see below. If the expected autorun behaviour worked ie wait for the Go button, then we would not have to workaround it but for now, its a pretty good solution. It was an enjoyable hour or so for me, took me back to my developer daze, when we used to race each other for the most number of bug fixes. I used to run a distant 2nd behind 'Bugmeister Chen Hu' but led the chasing pack by a reasonable distance.

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