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  • Help me clean up this crazy lambda with the out keyword

    - by Sarah Vessels
    My code looks ugly, and I know there's got to be a better way of doing what I'm doing: private delegate string doStuff( PasswordEncrypter encrypter, RSAPublicKey publicKey, string privateKey, out string salt ); private bool tryEncryptPassword( doStuff encryptPassword, out string errorMessage ) { ...get some variables... string encryptedPassword = encryptPassword(encrypter, publicKey, privateKey, out salt); ... } This stuff so far doesn't bother me. It's how I'm calling tryEncryptPassword that looks so ugly, and has duplication because I call it from two methods: public bool method1(out string errorMessage) { string rawPassword = "foo"; return tryEncryptPassword( (PasswordEncrypter encrypter, RSAPublicKey publicKey, string privateKey, out string salt) => encrypter.EncryptPasswordAndDoStuff( // Overload 1 rawPassword, publicKey, privateKey, out salt ), out errorMessage ); } public bool method2(SecureString unencryptedPassword, out string errorMessage) { return tryEncryptPassword( (PasswordEncrypter encrypter, RSAPublicKey publicKey, string privateKey, out string salt) => encrypter.EncryptPasswordAndDoStuff( // Overload 2 unencryptedPassword, publicKey, privateKey, out salt ), out errorMessage ); } Two parts to the ugliness: I have to explicitly list all the parameter types in the lambda expression because of the single out parameter. The two overloads of EncryptPasswordAndDoStuff take all the same parameters except for the first parameter, which can either be a string or a SecureString. So method1 and method2 are pretty much identical, they just call different overloads of EncryptPasswordAndDoStuff. Any suggestions? Edit: if I apply Jeff's suggestions, I do the following call in method1: return tryEncryptPassword( (encrypter, publicKey, privateKey) => { var result = new EncryptionResult(); string salt; result.EncryptedValue = encrypter.EncryptPasswordAndDoStuff( rawPassword, publicKey, privateKey, out salt ); result.Salt = salt; return result; }, out errorMessage ); Much the same call is made in method2, just with a different first value to EncryptPasswordAndDoStuff. This is an improvement, but it still seems like a lot of duplicated code.

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  • Parsing custom time format with SimpleDateFormat

    - by ggrigery
    I'm having trouble parsing a date format that I'm getting back from an API and that I have never seen (I believe is a custom format). An example of a date: /Date(1353447000000+0000)/ When I first encountered this format it didn't take me long to see that it was the time in milliseconds with a time zone offset. I'm having trouble extracting this date using SimpleDateFormat though. Here was my first attempt: String weirdDate = "/Date(1353447000000+0000)/"; SimpleDateFormat sdf = new SimpleDateFormat("'/Date('SSSSSSSSSSSSSZ')/'"); Date d1 = sdf.parse(weirdDate); System.out.println(d1.toString()); System.out.println(d1.getTime()); System.out.println(); Date d2 = new Date(Long.parseLong("1353447000000")); System.out.println(d2.toString()); System.out.println(d2.getTime()); And output: Tue Jan 06 22:51:41 EST 1970 532301760 Tue Nov 20 16:30:00 EST 2012 1353447000000 The date (and number of milliseconds parsed) is not even close and I haven't been able to figure out why. After some troubleshooting, I discovered that the way I'm trying to use SDF is clearly flawed. Example: String weirdDate = "1353447000000"; SimpleDateFormat sdf = new SimpleDateFormat("S"); Date d1 = sdf.parse(weirdDate); System.out.println(d1.toString()); System.out.println(d1.getTime()); And output: Wed Jan 07 03:51:41 EST 1970 550301760 I can't say I've ever tried to use SDF in this way to just parse a time in milliseconds because I would normally use Long.parseLong() and just pass it straight into new Date(long) (and in fact the solution I have in place right now is just a regular expression and parsing a long). I'm looking for a cleaner solution that I can easily extract this time in milliseconds with the timezone and quickly parse out into a date without the messy manual handling. Anyone have any ideas or that can spot the errors in my logic above? Help is much appreciated.

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  • Object-oriented GUI development in python

    - by ptabatt
    Hey guys, new programmer here. I have an assignment for class and I'm stuck... What I need to do is a create a GUI that gives someone a basic arithmetic problem in one box, asks the person to answer it, evaluates it, and tells you if you're right or wrong... Basically, what I have is this: [code] class Lesson(Frame): def init (self, parent=None): Frame.init(self, parent) self.pack() Lesson.make_widgets(self) def make_widgets(self): Label(self, text="").pack(side=TOP) ent = Entry(self) self.a = randrange(1,10) self.b = randrange(1,10) self.expr = choice(["+","-"]) ent.insert(END, str(self.a) + str(self.expr) + str(self.a)) [/code] I've broken this down into many little steps and basically, what I'm trying to do right now is insert a default random expression into the first entry widget. When I run this code, I just get a blank Label. Why is that? How can I put a something like "7+7" into the box? If you absolutely need background to the problem, it's question #3 on this link. http://reed.cs.depaul.edu/lperkovic/csc242/homeworks/Homework8.html -Thanks for all help in advance.

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  • Flexible forms and supporting database structure

    - by sunwukung
    I have been tasked with creating an application that allows administrators to alter the content of the user input form (i.e. add arbitrary fields) - the contents of which get stored in a database. Think Modx/Wordpress/Expression Engine template variables. The approach I've been looking at is implementing concrete tables where the specification is consistent (i.e. user profiles, user content etc) and some generic field data tables (i.e. text, boolean) to store non-specific values. Forms (and model fields) would be generated by first querying the tables and retrieving the relevant columns - although I've yet to think about how I would setup validation. I've taken a look at this problem, and it seems to be indicating an EAV type approach - which, from my brief research - looks like it could be a greater burden than the blessings it's flexibility would bring. I've read a couple of posts here, however, which suggest this is a dangerous route: How to design a generic database whose layout may change over time? Dynamic Database Schema I'd appreciate some advice on this matter if anyone has some to give regards SWK

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  • Practice of checking 'trueness' or 'equality' in conditional statements - does it really make sense?

    - by Senthil
    I remember many years back, when I was in school, one of my computer science teachers taught us that it was better to check for 'trueness' or 'equality' of a condition and not the negative stuff like 'inequality'. Let me elaborate - If a piece of conditional code can be written by checking whether an expression is true or false, we should check the 'trueness'. Example: Finding out whether a number is odd - it can be done in two ways: if ( num % 2 != 0 ) { // Number is odd } or if ( num % 2 == 1 ) { // Number is odd } When I was beginning to code, I knew that num % 2 == 0 implies the number is even, so I just put a ! there to check if it is odd. But he was like 'Don't check NOT conditions. Have the practice of checking the 'trueness' or 'equality' of conditions whenever possible.' And he recommended that I use the second piece of code. I am not for or against either but I just wanted to know - what difference does it make? Please don't reply 'Technically the output will be the same' - we ALL know that. Is it a general programming practice or is it his own programming practice that he is preaching to others?

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  • PHP header location redirect causing 500 Internal Server error

    - by Globalz
    Hi, I I keep getting a 500 Internal Server Error when the script below reaches the header('location:php_email_thankyou.php'). Im not sure what is causing this, as I can place the header expression before or after the if statements and it works fine. In firebug it mentions a GET request for the php_email_thankyou.php page not sure if that means anything... <?php ini_set('display_errors', 'On'); error_reporting(E_ALL | E_STRICT); include('php/cl/cl_val.php'); $val = new Validate; $print_errors = false; if (isset($_POST['email(email)'])){ if(isset($_SERVER['HTTP_X_REQUESTED_WITH'])) { $validation = $val->clean($_POST); if (isset($validation['send'])) { header('location:php_email_thankyou.php'); exit(); } else { print json_encode($validation); exit(); } } else { $validation = $val->clean($_POST); } } ?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> Thanks heaps!

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  • prototype findElements querySelectorAll error

    - by JD
    i'm call the "down" function but am getting an invalid argument using 1.6.1_rc2 here's the html snippet: <TR id=000000214A class="activeRow searchResultsDisplayOver" conceptID="0000001KIU"> <TD> <DIV class=gridRowWrapper> <SPAN class=SynDesc>Asymmetric breasts</SPAN> <DIV class=buttonWrapper> <SPAN class=btnAddFav title="Add to Favorites">&nbsp;</SPAN> </DIV> </DIV> </TD> </TR> here's the code: var description = row.down('span.SynDesc').innerHTML; row is a dom reference to the element. prototype is appending a # then the id of the element: findElements: function(root) { root = root || document; var e = this.expression, results; switch (this.mode) { case 'selectorsAPI': if (root !== document) { var oldId = root.id, id = $(root).identify(); id = id.replace(/[\.:]/g, "\\$0"); e = "#" + id + " " + e; } results = $A(root.querySelectorAll(e)).map(Element.extend); <-- e = "#000000214A span.SynDesc" root.id = oldId; return results; case 'xpath': return document._getElementsByXPath(this.xpath, root); default: return this.matcher(root); } i get an "invalid argument" error? if i put a breakpoint before the offending line and change e to be equal to "span.SynDesc" it works fine. help. :)

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  • c++ and c# speed compared

    - by Mack
    I was worried about C#'s speed when it deals with heavy calculations, when you need to use raw CPU power. I always thought that C++ is much faster than C# when it comes to calculations. So I did some quick tests. The first test computes prime numbers < an integer n, the second test computes some pandigital numbers. The idea for second test comes from here: Pandigital Numbers C# prime computation: using System; using System.Diagnostics; class Program { static int primes(int n) { uint i, j; int countprimes = 0; for (i = 1; i <= n; i++) { bool isprime = true; for (j = 2; j <= Math.Sqrt(i); j++) if ((i % j) == 0) { isprime = false; break; } if (isprime) countprimes++; } return countprimes; } static void Main(string[] args) { int n = int.Parse(Console.ReadLine()); Stopwatch sw = new Stopwatch(); sw.Start(); int res = primes(n); sw.Stop(); Console.WriteLine("I found {0} prime numbers between 0 and {1} in {2} msecs.", res, n, sw.ElapsedMilliseconds); Console.ReadKey(); } } C++ variant: #include <iostream> #include <ctime> int primes(unsigned long n) { unsigned long i, j; int countprimes = 0; for(i = 1; i <= n; i++) { int isprime = 1; for(j = 2; j < (i^(1/2)); j++) if(!(i%j)) { isprime = 0; break; } countprimes+= isprime; } return countprimes; } int main() { int n, res; cin>>n; unsigned int start = clock(); res = primes(n); int tprime = clock() - start; cout<<"\nI found "<<res<<" prime numbers between 1 and "<<n<<" in "<<tprime<<" msecs."; return 0; } When I ran the test trying to find primes < than 100,000, C# variant finished in 0.409 seconds and C++ variant in 5.553 seconds. When I ran them for 1,000,000 C# finished in 6.039 seconds and C++ in about 337 seconds. Pandigital test in C#: using System; using System.Diagnostics; class Program { static bool IsPandigital(int n) { int digits = 0; int count = 0; int tmp; for (; n > 0; n /= 10, ++count) { if ((tmp = digits) == (digits |= 1 << (n - ((n / 10) * 10) - 1))) return false; } return digits == (1 << count) - 1; } static void Main() { int pans = 0; Stopwatch sw = new Stopwatch(); sw.Start(); for (int i = 1; i <= 123456789; i++) { if (IsPandigital(i)) { pans++; } } sw.Stop(); Console.WriteLine("{0}pcs, {1}ms", pans, sw.ElapsedMilliseconds); Console.ReadKey(); } } Pandigital test in C++: #include <iostream> #include <ctime> using namespace std; int IsPandigital(int n) { int digits = 0; int count = 0; int tmp; for (; n > 0; n /= 10, ++count) { if ((tmp = digits) == (digits |= 1 << (n - ((n / 10) * 10) - 1))) return 0; } return digits == (1 << count) - 1; } int main() { int pans = 0; unsigned int start = clock(); for (int i = 1; i <= 123456789; i++) { if (IsPandigital(i)) { pans++; } } int ptime = clock() - start; cout<<"\nPans:"<<pans<<" time:"<<ptime; return 0; } C# variant runs in 29.906 seconds and C++ in about 36.298 seconds. I didn't touch any compiler switches and bot C# and C++ programs were compiled with debug options. Before I attempted to run the test I was worried that C# will lag well behind C++, but now it seems that there is a pretty big speed difference in C# favor. Can anybody explain this? C# is jitted and C++ is compiled native so it's normal that a C++ will be faster than a C# variant. Thanks for the answers!

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  • Why is a Silverlight application created from an exported template show a blank screen in the browse

    - by Edward Tanguay
    I created a silverlight app (without website) named TestApp, with one TextBox: <UserControl x:Class="TestApp.MainPage" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" mc:Ignorable="d" d:DesignWidth="640" d:DesignHeight="480"> <Grid x:Name="LayoutRoot"> <TextBlock Text="this is a test"/> </Grid> </UserControl> I press F5 and see "this is a test" in my browser (firefox). I select File | Export Template | name it TestAppTemplate and save it. I create a new silverlight app based on the above template. The MainPage.xaml has the exact same XAML as above. I press F5 and see a blank screen in my browser. I look at the HTML source of both of these and they are identical. Everything I have compared in both projects is identical. What do I have to do so that a Silverlight application which is created from my exported template does not show a blank screen?

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  • What do you mean by the expressiveness in programming lanuguage?

    - by prosseek
    I see a lot of the word 'expressiveness' when people want to stress one language is better than the other. But I don't see exactly what they mean by it. Is it the verboseness/succinctness? I mean, if one language can write down something shorter than the other, does that mean expressiveness? Please refer to my other question - http://stackoverflow.com/questions/2411772/article-about-code-density-as-a-measure-of-programming-language-power Is it the power of the language? Paul Graham says that one language is more powerful than the other language in a sense that one language can do that the other language can't do (for example, LISP can do something with macro that the other language can't do). Is it just something that makes life easier? Regular expression can be one of the examples. Is it a different way of solving the same problem: something like SQL to solve the search problem? What do you think about the expressiveness of a programming lanuage? Can you show the expressiveness using some code? What's the relationship with the expressiveness and DSL? Do people come up with DSL to get the expressiveness?

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  • How can I redirect directory using htaccess including files with spaces in the names

    - by James
    Hi, I am dealing with a situation where someone has handed me a bunch of old files on the server which already have a lot of incoming links directly to them (mostly pdf files). I now have the files organized but in a different directory. Before it was 'domain/manuals/file' now it is 'domain/media/manual/file'. I am trying to resolve this issue using an htaccess file. Many of the files have spaces in the names (not something I can control) and because they already have links to them I can't just go through renaming them. I have found that I can redirect files individually when they have spaces in the names by using quotes such as: redirect 301 "/manuals/file 123.pdf" "http://www.domain.com/manuals/file 123.pdf" However, there are loads of these files and I wondered if there is a way to create a regular expression that will handle spaces in file names that I could use to redirect the entire directory. I should add that some files contain decent file names with no spaces in, some have one space and others more than one space. It's not pretty. If you've encountered this problem before I would really appreciate hearing your advice, I'm running out of ideas. Thanks.

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  • NHibernate query against the key field of a dictionary (map)

    - by Carl Raymond
    I have an object model where a Calendar object has an IDictionary<MembershipUser, Perms> called UserPermissions, where MembershipUser is an object, and Perms is a simple enumeration. This is in the mapping file for Calendar as <map name="UserPermissions" table="CalendarUserPermissions" lazy="true" cascade="all"> <key column="CalendarID"/> <index-many-to-many class="MembershipUser" column="UserGUID" /> <element column="Permissions" type="CalendarPermission" not-null="true" /> </map> Now I want to execute a query to find all calendars for which a given user has some permission defined. The permission is irrelevant; I just want a list of the calendars where a given user is present as a key in the UserPermissions dictionary. I have the username property, not a MembershipUser object. How do I build that using QBC (or HQL)? Here's what I've tried: ISession session = SessionManager.CurrentSession; ICriteria calCrit = session.CreateCriteria<Calendar>(); ICriteria userCrit = calCrit.CreateCriteria("UserPermissions.indices"); userCrit.Add(Expression.Eq("Username", username)); return calCrit.List<Calendar>(); This constructed invalid SQL -- the WHERE clause contained WHERE membership1_.Username = @p0 as expected, but the FROM clause didn't include the MemberhipUsers table. Also, I really had to struggle to learn about the .indices notation. I found it by digging through the NHibernate source code, and saw that there's also .elements and some other dotted notations. Where's a reference to the allowed syntax of an association path? I feel like what's above is very close, and just missing something simple.

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  • How can I define a verb in J that applies a different verb alternately to each atom in a list?

    - by Gregory Higley
    Imagine I've defined the following name in J: m =: >: i. 2 4 5 This looks like the following: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 I want to create a monadic verb of rank 1 that applies to each list in this list of lists. It will double (+:) or add 1 (>:) to each alternate item in the list. If we were to apply this verb to the first row, we'd get 2 3 6 5 10. It's fairly easy to get a list of booleans which alternate with each item, e.g., 0 1 $~{:$ m gives us 0 1 0 1 0. I thought, aha! I'll use something like +:`>: @. followed by some expression, but I could never quite get it to work. Any suggestions? UPDATE The following appears to work, but perhaps it can be refactored into something more elegant by a J pro. poop =: monad define (($ y) $ 0 1 $~{:$ y) ((]+:)`(]:) @. [)"0 y )

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  • Generic validate input data via regex. Input error when match.count == 0

    - by Valamas
    Hi, I have a number of types of data fields on an input form, for example, a web page. Some fields are like, must be an email address, must be a number, must be a number between, must have certain characters. Basically, the list is undefinable. I wish to come up with a generic way of validating the data inputed. I thought I would use regex to validate the data. The fields which need validation would be related to a "regex expression" and a "regex error message" stating what the field should contain. My current mock up has that when the match count is zero, that would signify an error and to display the message. While still a white belt regex designer I have come to understand that in certain situations that it is difficult to write a regex which results in a match count of zero for every case. A complex regex case I looked for help on was Link Here. The forum post was a disaster because I confused people helping me. But one of the statements said that it was difficult to make a regex with a match count of zero meaning the input data was invalid; that the regex was very difficult to write that for. Does anyone have comments or suggestions on this generic validation system I am trying to create? thanks

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  • Returning data from SQL Server reporting web service call

    - by user79339
    Hi, I am generating a report that contains the version number. The version number is stored in the DB and retrieved/incremented as part of the report generation. The only problem is, I am calling SSRS via a web service call, which returns the generated report as a byte array. Is there any way to get the version number out of this generated report? For example to display a dialog that says "You generated Status Report, Version number 3". I tried passing in an output parameter and setting it inside the storedproc. Its modified when i execute it in sql management studio, but not in the reporting studio. Or atleast i can't seem to bind to the modified, post execution value (using expression "=Parameters!ReportVersion.Value"). Of course, I could get/increment the version number from database myself before calling the SSRS webservice and pass it along as a parameter to the Report, but that might cause concurrancy problems. On the whole, it just seems neater for the storedproc to access/generate a version number and return it to the ReportingEngine, which will generate the report with the version number and return the updated version number to the WebService client. Any thoughts/Ideas?

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  • How to capture strings using * or ? with groups in python regular expressions

    - by user1334085
    When the regular expression has a capturing group followed by "*" or "?", there is no value captured. Instead if you use "+" for the same string, you can see the capture. I need to be able to capture the same value using "?" >>> str1='This string has 29 characters' >>> re.search(r'(\d+)*', str1).group(0) '' >>> re.search(r'(\d+)*', str1).group(1) >>> >>> re.search(r'(\d+)+', str1).group(0) '29' >>> re.search(r'(\d+)+', str1).group(1) '29' More specific question is added below for clarity: I have str1 and str2 below, and I want to use just one regexp which will match both. In case of str1, I also want to be able to capture the number of QSFP ports >>> str1='''4 48 48-port and 6 QSFP 10GigE Linecard 7548S-LC''' >>> str2='''4 48 48-port 10GigE Linecard 7548S-LC''' >>> When I do not use a metacharacter, the capture works: >>> re.search(r'^4\s+48\s+.*(?:(\d+)\s+QSFP).*-LC', str1, re.I|re.M).group(1) '6' >>> It works even when I use the "+" to indicate one occurrence: >>> re.search(r'^4\s+48\s+.*(?:(\d+)\s+QSFP)+.*-LC', str1, re.I|re.M).group(1) '6' >>> But when I use "?" to match for 0 or 1 occurrence, the capture fails even for str1: >>> re.search(r'^4\s+48\s+.*(?:(\d+)\s+QSFP)?.*-LC', str1, re.I|re.M).group(1) >>>

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  • JQuery validate e-mail address regex

    - by RussP
    Hi folks, not too sure about how to do this. I need/want to validate email addresses by regex using something like this: [a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*@(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+(?:[A-Z]{2}|com|org|net|edu|gov|mil|biz|info|mobi|name|aero|asia|jobs|museum) Not I need to run this in a JQ function like this: Where does the validation go and wht is the expression? - please $j("#fld_emailaddress").live('change',function() { var emailaddress = $j("#fld_emailaddress").val(); // validation here? if(emailaddress){} // end validation $j.ajax({ type: "POST", url: "../ff-admin/ff-register/ff-user-check.php", data: "fld_emailaddress="+ emailaddress, success: function(msg) { if(msg == 'OK') { $j("#fld_username").attr('disabled',false); $j("#fld_password").attr('disabled',false); $j("#cmd_register_submit").attr('disabled',false); $j("#fld_emailaddress").removeClass('object_error'); // if necessary $j("#fld_emailaddress").addClass("object_ok"); $j('#email_ac').html('&nbsp;<img src="img/cool.png" align="absmiddle"> <font color="Green"> Your email <strong>'+ emailaddress+'</strong> is OK.</font> '); } else { $j("#fld_username").attr('disabled',true); $j("#fld_password").attr('disabled',true); $j("#cmd_register_submit").attr('disabled',true); $j("#fld_emailaddress").removeClass('object_ok'); // if necessary $j("#fld_emailaddress").addClass("object_error"); $j('#email_ac').html(msg); } } }); });

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  • How to extract ALL typedefs and structs and unions from c++ source

    - by Michael Wells
    I have inherited a Visual Studio project that contains hundreds of files. I would like to extract all the typedefs, structs and unions from each .h/.cpp file and put the results in a file). Each typdef/struct/union should be on one line in the results file. This would make sorting much easier. typdef int myType; struct myFirstStruct { char a; int b;...}; union Part_Number_Serial_Number_Part_2_Response_Message_Type {struct{Message_Response_Head_Type Head; Part_Num_Serial_Num_Part_2_Report_Array Part_2_Report; Message_Tail_Type Tail;} Data; BYTE byData[140];}myUnion; struct { bool c; int d;...}mySecondStruct; My problem is, I do not know what to look for (grammar of typedef/structs/unions) using a regular expression. I cannot believe that nobody has done this before (I googled and have not found anything on this). Does anyone know the regular expressions for these? (Note some are commented out using // others /* */) Or a tool to accomplish this. Edit: I am toying with the idea of autogenerating source code and/or dialogs for modifying messages that use the underlying typedef/struct/union. I was going to use the output to generate an XML file that could be used for this reason. The source for these are in C/C++ and used in almost all my projects. These projects are usually NOT in C/C++. By using the XML version I would only need to update/add the typedef/struct/union only in one place and all the projects would be able to autogen the source and/or dialogs.

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  • EF/LINQ: Where() against a property of a subtype

    - by ladenedge
    I have a set of POCOs, all of which implement the following simple interface: interface IIdObject { int Id { get; set; } } A subset of these POCOs implement this additional interface: interface IDeletableObject : IIdObject { bool IsDeleted { get; set; } } I have a repository hierarchy that looks something like this: IRepository<T <: BasicRepository<T <: ValidatingRepository<T (where T is IIdObject) I'm trying to add a FilteringRepository to the hierarchy such that all of the POCOs that implement IDeletableObject have a Where(p => p.IsDeleted == false) filter applied before any other queries take place. My goal is to avoid duplicating the hierarchy solely for IDeletableObjects. My first attempt looked like this: public override IQueryable<T> Query() { return base.Query().Where(t => ((IDeletableObject)t).IsDeleted == false); } This works well with LINQ to Objects, but when I switch to an EF backend I get: "LINQ to Entities only supports casting Entity Data Model primitive types." I went on to try some fancier parameterized solutions, but they ultimately failed because I couldn't make T covariant in the following case for some reason I don't quite understand: interface IQueryFilter<out T> // error { Expression<Func<T, bool>> GetFilter(); } I'd be happy to go into more detail on my more complicated solutions if it would help, but I think I'll stop here for now in hope that someone might have an idea for me to try. Thanks very much in advance!

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  • Trying to match variables in a PHP array

    - by Nick B
    I'm stuck with a php array problem. I've to a webpage that takes values from a URL, and I need to cross reference those values against some values on the page and if they match output a 'yes'. It's an expression engine bodge job. The URL is something like domain.com/page/C12&C14 The C12 and C14 represent different categories. I've taken the last bit of the url, removed the 'C' from the values and then exploded the 12&14 into an array. I print_r the array on the page and it shows: Array ( [0] = 12 [1] = 14 ) So, the values are in the array. Lovely. Now on the page I have an html list which looks like 10 12 14 15 I want to output a YES next to the variables that are current in the array so the ideal output would be: 10 12 - YES 14 - YES 15 I was trying this but it keeps just saying No next to all of them. $currentnumber = 12; foreach ($tharray as $element) { if ($element == $currentnumber) { echo "Yes"; } else { echo "No"; } } I thought that should work, but it's not. I checked and the array and the variable are both stings. I did a strlen() on both to see if they are the same, but $currentnumber outputs '13' and the array variable outputs '2'. Any ideas as to why it's saying 13? Is the variable the wrong type of string - and if so how would I convert it?

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  • Problem with circular definition in Scheme

    - by user8472
    I am currently working through SICP using Guile as my primary language for the exercises. I have found a strange behavior while implementing the exercises in chapter 3.5. I have reproduced this behavior using Guile 1.4, Guile 1.8.6 and Guile 1.8.7 on a variety of platforms and am certain it is not specific to my setup. This code works fine (and computes e): (define y (integral (delay dy) 1 0.001)) (define dy (stream-map (lambda (x) x) y)) (stream-ref y 1000) The following code should give an identical result: (define (solve f y0 dt) (define y (integral (delay dy) y0 dt)) (define dy (stream-map f y)) y) (solve (lambda (x) x) 1 0.001) But it yields the error message: standard input:7:14: While evaluating arguments to stream-map in expression (stream-map f y): standard input:7:14: Unbound variable: y ABORT: (unbound-variable) So when embedded in a procedure definition, the (define y ...) does not work, whereas outside the procedure in the global environment at the REPL it works fine. What am I doing wrong here? I can post the auxiliary code (i.e., the definitions of integral, stream-map etc.) if necessary, too. With the exception of the system-dependent code for cons-stream, they are all in the book. My own implementation of cons-stream for Guile is as follows: (define-macro (cons-stream a b) `(cons ,a (delay ,b)))

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  • Java: Help constructing a fillTextFields() method

    - by Holly
    I have a Java project where I am to connect to a database and create buttons (next, new, save, delete, previous) to navigate through the database content where there are appropriate text fields and labels for the specific information. I'll use the code below as an example (each button is set up very similar)... I have it as follows: JButton jbtnNext = new JButton("Next ->"); jbtnNext.addActionListener(this); if (e.getSource() == jbtnNext) jbtnNext_Click(); private void jbtnNext_Click() { JOptionPane.showMessageDialog(null, "Next" ,"Button Pressed", JOptionPane.INFORMATION_MESSAGE); try { if (rset.next()) { fillTextFields(true); }else{ //Display result in a dialog box JOptionPane.showMessageDialog(null, "Not found"); } } catch (SQLException ex) { ex.printStackTrace(); } } The professor gave the following outline of logic to construct the fillTextFields() method: Construct the method to provide reusable code that would fill the JTextFields on the GUI with appropriate values from current record from the database (when "Previous or "Next" buttons are pressed) or blank values (when the new Button is pressed). To determine when the current record was to provide values (next and previous) or the value would be blank (new button) pass a boolean argument into the method. If data from the current record was to be used as fill values, pass true for both previous and next button code after moving the record pointer. If the new button was pressed and want to fill with blank values, pass false to the method. Inside the method, use a conditional expression to evaluate the boolean variable. If true, The appropriate get----() resultset method is used to fill the JTextFields. If false, fill them with "". The .setText() method of the JTextField is used to fill each JTextField. Make sure the fillTextFields method throws the appropriate exception. I understand and have the previous and next button methods passing true, while the new button method is passing false, but I don't quite understand how to set up the fillTextFields() method correctly or how to "throw the appropriate exception"... Any help would really be appreciated, thank you!

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  • Nullability (Regular Expressions)

    - by danportin
    In Brzozowski's "Derivatives of Regular Expressions" and elsewhere, the function d(R) returning ? if a R is nullable, and Ø otherwise, includes clauses such as the following: d(R1 + R2) = d(R1) + d(R2) d(R1 · R2) = d(R1) ? d(R2) Clearly, if both R1 and R2 are nullable then (R1 · R2) is nullable, and if either R1 or R2 is nullable then (R1 + R2) is nullable. It is unclear to me what the above clauses are supposed to mean, however. My first thought, mapping (+), (·), or the Boolean operations to regular sets is nonsensical, since in the base case, d(a) = Ø (for all a ? S) d(?) = ? d(Ø) = Ø and ? is not a set (nor is the return type of d, which is a regular expression). Furthermore, this mapping isn't indicated, and there is a separate notation for it. I understand nullability, but I'm lost on the definition of the sum, product, and Boolean operations in the definition of d: how are ? or Ø returned from d(R1) ? d(R2), for instance, in the definition off d(R1 · R2)?

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  • How do I use the Enum value from a class in another part of code?

    - by ChiggenWingz
    Coming from a C# background from a night course at a local college, I've sort of started my way in C++. Having a lot pain getting use to the syntax. I'm also still very green when it comes to coding techniques. From my WinMain function, I want to be able to access a variable which is using an enum I declared in another class. (inside core.h) class Core { public: enum GAME_MODE { INIT, MENUS, GAMEPLAY }; GAME_MODE gameMode; Core(); ~Core(); ...OtherFunctions(); }; (inside main.cpp) Core core; int WINAPI WinMain(...) { ... startup code here... core.gameMode = Core.GAME_MODE.INIT; ...etc... } Basically I want to set that gameMode to the enum value of Init or something like that from my WinMain function. I want to also be able to read it from other areas. I get the error... expected primary-expression before '.' token If I try to use core.gameMode = Core::GAME_MODE.INIT;, then I get the same error. I'm not fussed about best practices, as I'm just trying to get the basic understanding of passing around variables in C++ between files. I'll be making sure variables are protected and neatly tucked away later on once I am use to the flexibility of the syntax. If I remember correctly, C# allowed me to use Enums from other classes, and all I had to do was something like Core.ENUMNAME.ENUMVALUE. I hope what I'm wanting to do is clear :\ As I have no idea what a lot of the correct terminology is.

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  • Replacing all GUIDs in a file with new GUIDs from the command line

    - by Josh Petrie
    I have a file containing a large number of occurrences of the string Guid="GUID HERE" (where GUID HERE is a unique GUID at each occurrence) and I want to replace every existing GUID with a new unique GUID. This is on a Windows development machine, so I can generate unique GUIDs with uuidgen.exe (which produces a GUID on stdout every time it is run). I have sed and such available (but no awk oddly enough). I am basically trying to figure out if it is possible (and if so, how) to use the output of a command-line program as the replacement text in a sed substitution expression so that I can make this replacement with a minimum of effort on my part. I don't need to use sed -- if there's another way to do it, such as some crazy vim-fu or some other program, that would work as well -- but I'd prefer solutions that utilize a minimal set of *nix programs since I'm not really on *nix machines. To be clear, if I have a file like this: etc etc Guid="A" etc etc Guid="B" I would like it to become this: etc etc Guid="C" etc etc Guid="D" where A, B, C, D are actual GUIDs, of course. (for example, I have seen xargs used for things similar to this, but it's not available on the machines I need this to run on, either. I could install it if it's really the only way, although I'd rather not)

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