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  • Problem with do construct in haskell

    - by Anonymous Coward
    Hello everyone I'm trying to learn Haskell and want to write a small program which prints the content of a file to the screen. When I load it into GHCi I get the following error: The last statement in a 'do' construct must be an expression I know this question has be asked already here: Haskell — “The last statement in a 'do' construct must be an expression”. Even though my code is very similar I still can't figure out the problem. If anyone could point out the problem to me I'd be very thankful. module Main (main) where import System.IO import System(getArgs) main :: IO() main = do args <- getArgs inh <- openFile $ ReadMode head args printFile inh hClose inh printFile :: Handle -> IO () printFile handle = do end <- hIsEOF handle if end then return () else do line <- hGetLine handle putStrLn line printFile handle

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  • Linq Query Giving Error

    - by user275561
    I am getting this error when I use the Linq expression of var emp = _testModel.Where(m => m.Date == DateTime.Now).Select(m=>m); 'System.Collections.Generic.IEnumerable' does not contain a definition for 'System' and no extension method 'System' accepting a first argument of type 'System.Collections.Generic.IEnumerable' could be found (are you missing a using directive or an assembly reference?). I have google'd and looked everywhere by I have no idea what it is talking about? It doesn't throw an exception. The only way I found out about this was stepping through the expression.

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  • Python __setattr__ and __getattr__ for global scope?

    - by KT
    Suppose I need to create my own small DSL that would use Python to describe a certain data structure. E.g. I'd like to be able to write something like f(x) = some_stuff(a,b,c) and have Python, instead of complaining about undeclared identifiers or attempting to invoke the function some_stuff, convert it to a literal expression for my further convenience. It is possible to get a reasonable approximation to this by creating a class with properly redefined __getattr__ and __setattr__ methods and use it as follows: e = Expression() e.f[e.x] = e.some_stuff(e.a, e.b, e.c) It would be cool though, if it were possible to get rid of the annoying "e." prefixes and maybe even avoid the use of []. So I was wondering, is it possible to somehow temporarily "redefine" global name lookups and assignments? On a related note, maybe there are good packages for easily achieving such "quoting" functionality for Python expressions?

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  • Collectable<T> serialization, Root Namespaces on T in .xml files.

    - by Stacey
    I have a Repository Class with the following method... public T Single<T>(Predicate<T> expression) { using (var list = (Models.Collectable<T>)System.Xml.Serializer.Deserialize(typeof(Models.Collectable<T>), FileName)) { return list.Find(expression); } } Where Collectable is defined.. [Serializable] public class Collectable<T> : List<T>, IDisposable { public Collectable() { } public void Dispose() { } } And an Item that uses it is defined.. [Serializable] [System.Xml.Serialization.XmlRoot("Titles")] public partial class Titles : Collectable<Title> { } The problem is when I call the method, it expects "Collectable" to be the XmlRoot, but the XmlRoot is "Titles" (all of object Title). I have several classes that are collected in .xml files like this, but it seems pointless to rewrite the basic methods for loading each up when the generic accessors do it - but how can I enforce the proper root name for each file without hard coding methods for each one? The [System.Xml.Serialization.XmlRoot] seems to be ignored.

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  • Converting ObjC Blocks to C# Lambas

    - by Sam
    I need some help converting an Objective-C block to C#. Here is the source ObjC: NSDate* addYear = [_calendar dateByAddingComponents:((^{ NSDateComponents* components = [NSDateComponents new]; components.month = 12; return components; })()) toDate:now options:0]; Now I tried the following in C#: NSDate date = _calendar.DateByAddingComponents((() => { NSDateComponents components = new NSDateComponents(); components.Month = 12; return components; })(), now, NSCalendarOptions.None); To which I get the following compiler error: Expression denotes a 'anonymous method' where a 'method group' was expected. Removing the parentheses around the lambda yields Cannot convert 'lambda expression' to non-delegate type 'MonoTouch.Foundation.NSDateComponents'. What is the correct C# syntax? I need to retain the closures as there are a lot more in the code base that I am porting.

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  • Why does concatenating strings in the argument of EXEC sometimes cause a syntax error in T-SQL?

    - by Tim Goodman
    In MS SQL Server Management Studio 2005, running this code EXEC('SELECT * FROM employees WHERE employeeID = ' + CAST(3 AS VARCHAR)) gives this error: Incorrect syntax near 'CAST' However, if I do this, it works: DECLARE @temp VARCHAR(4000) SET @temp = 'SELECT * FROM employees WHERE employeeID = ' + CAST(3 AS VARCHAR) EXEC(@temp) I found an explanation here: http://stackoverflow.com/questions/1044831/t-sql-cannot-pass-concatenated-string-as-argument-to-stored-procedure According to the accepted answer, EXEC can take a local variable or a value as its argument, but not an expression. However, if that's the case, why does this work: DECLARE @temp VARCHAR(4000) SET @temp = CAST(3 AS VARCHAR) EXEC('SELECT * FROM employees WHERE employeeID = ' + @temp) 'SELECT * FROM employees WHERE employeeID = ' + @temp sure looks like an expression to me, but the code executes with no errors.

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  • C++ vector and segmentation faults

    - by Headspin
    I am working on a simple mathematical parser. Something that just reads number = 1 + 2; I have a vector containing these tokens. They store a type and string value of the character. I am trying to step through the vector to build an AST of these tokens, and I keep getting segmentation faults, even when I am under the impression my code should prevent this from happening. Here is the bit of code that builds the AST: struct ASTGen { const vector<Token> &Tokens; unsigned int size, pointer; ASTGen(const vector<Token> &t) : Tokens(t), pointer(0) { size = Tokens.size() - 1; } unsigned int next() { return pointer + 1; } Node* Statement() { if(next() <= size) { switch(Tokens[next()].type) { case EQUALS : Node* n = Assignment_Expr(); return n; } } advance(); } void advance() { if(next() <= size) ++pointer; } Node* Assignment_Expr() { Node* lnode = new Node(Tokens[pointer], NULL, NULL); advance(); Node* n = new Node(Tokens[pointer], lnode, Expression()); return n; } Node* Expression() { if(next() <= size) { advance(); if(Tokens[next()].type == SEMICOLON) { Node* n = new Node(Tokens[pointer], NULL, NULL); return n; } if(Tokens[next()].type == PLUS) { Node* lnode = new Node(Tokens[pointer], NULL, NULL); advance(); Node* n = new Node(Tokens[pointer], lnode, Expression()); return n; } } } }; ... ASTGen AST(Tokens); Node* Tree = AST.Statement(); cout << Tree->Right->Data.svalue << endl; I can access Tree->Data.svalue and get the = Node's token info, so I know that node is getting spawned, and I can also get Tree->Left->Data.svalue and get the variable to the left of the = I have re-written it many times trying out different methods for stepping through the vector, but I always get a segmentation fault when I try to access the = right node (which should be the + node) Any help would be greatly appreciated.

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  • How can i pass a single additional argument to array_map callback in PHP?

    - by Gremo
    How can i pass a single additional argument to array_map callback? In my example i'd like to pass $smsPattern (as a second argument, after current element in $featureNames) to the function array_map with $getLimit closure: $features = $usage->getSubscription()->getUser()->getRoles(); // SMS regular expression in the form of ROLE_SEND_SMS_X $smsPattern = '/^ROLE_SEND_SMS_(?P<l>\d+)$/i'; // Function to get roles names and X from a role name $getNames = function($r) { return trim($r->getRole()); }; $getLimit = function($name, $pattern) { if(preg_match($pattern, $name, $m)) return $m['l']; }; // Get roles names and their limits ignoring null values with array_filter $featuresNames = array_map($getNames, $features); $smsLimits = array_filter(array_map($getLimit, $featureNames, $smsPattern)); With this code i'm getting a weird warning: Warning: array_map() [function.array-map]: Argument #3 should be an array. Of course di reason is for reusing $getLimit closure with another regular expression like $smsPattern. Thanks.

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  • SQL Server Reporting Services Format Hours as Hours:Minutes

    - by Frank Schmitt
    I'm writing reports on SQL Server Reporting Server that have a number of hours grouped by, say, user, and a total calculated based on the sum of the values. Currently my query runs a stored proc that returns the hours as in HH:MM format, rather than decimal hours, as our users find that more intuitive. The problem occurs when I try and add up the column using an SSRS expression, because the SUM function isn't smart enough to handle adding up times in this format. Is there any way to: Display a time interval (in minutes or hours) in HH:MM format while having it calculated in decimal form? Or split up and calculate the total of the HH:MM text values to arrive at a total as an expression? I'd like to avoid having to write/run a second query just to get the total.

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  • Perl : How to get All grouped patterns

    - by pavun_cool
    I have this following code. Here I am matching the vowels characters words if ( /(a)+/ and /(e)+/ and /(i)+/ and /(o)+/ and /(u)+/ ) { print "$1#$2#$3#$4#$5\n"; $number++; } I am trying to get the all matched patterns using grouping . But I am getting only last expression pattern , which means fifth expression of if condition . Here I know that it is giving only one pattern because last pattern matching in if condition. But I want to get all matched patterns Any one help me out of this problem.

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  • How to make validation for a textbox that accept only comma(,) & digit in c# web application?

    - by prateeksaluja20
    Hello Experts, I am working on a website.I am using C# 2008.I want to make a text box that accept only numbers & comma(,). for example-919981424199,78848817711,47171111747 or there may be a single number like 919981424199. I was able to do one thing My text box only containing number by using this Regular Expression validation.in its property-Validation Expression i wrote "[0-9]+". This is working but now my requirement is to send bulk SMS & each number is separated by (,). I tried a lot but not getting the ans.so please help me to sort out this problem. Thanks in advance.

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  • No-argument method on window.external is invoked when checking with typeof

    - by janko
    Hi, I am trying to display an HTML page with embedded JavaScript code inside a System.Windows.Forms.WebBrowser control. The JavaScript code is expected to interact with the embedding environment through the window.external object. Before invoking a method on window.external, JavaScript is supposed to check for the existance of the method. If it is not there, the code should invoke a generic fallback method. // basic idea if (typeof(window.external.MyMethod) != 'undefined') { window.external.MyMethod(args); } else { window.external.Generic("MyMethod", args); } However, checking for a no-argument method with typeof seems to invoke the method already. That is, if MyMethod accepts any positive number of arguments, the code above will work perfectly; but, if MyMethod is a no-argument method, then the expression typeof(window.external.MyMethod) will not check for its type but invoke it, too. Is there any work-around to this behavior? Can I somehow escape the expression window.external.MyMethod to prevent the method call from occurring?

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  • Lookup function not working (RS SP2)

    - by Al Reyes
    Hi, I made the upgrade to SP2. I'm trying to use the Lookup function to link data from two different servers. I'm trying first a simple exercise linking data from two datasets from the same server, having one dataset with journals and the other with the account description. My Expression looks like this at a field on the table I have: =Lookup(Fields!ACTINDX.Value,Fields!ACTINDX.Value,Fields!ACTDESCR.Value,"ACCTINFO") I made sure of the names and using only uppercases for datasets and fields but I'm receiving the following message when I try to preview: "An error occurred during local report processing. The definition of the report '/DETAIL' is invalid. The Value expression for the text box 'ACTINDX' refers to the field 'ACTDESCR'. Report item expressions can only refer to fields within the current dataset scope or, if inside an aggregate, the specified dataset scope". I'll appreciate any suggestions. Regards, Al

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  • Winform .Net 3.5 - Get path of ApplicationFolder for Office Add-In

    - by Serexx
    Greetings - I am writing an add-in for Expression Web 3 in VS2008 The solution has a Windows Installer setup project in which the ApplicationFolder is tagged to hold some ancillary files. I need to be able to access those files during the add-in's startup, but naturally the Application object as well as the AppDomain reference paths to Expression Web not to the Add-In. There is a tickle in the back of my head that the solution involves reflection but thats as far as I can get... has anyone dealt with this or have any suggestions? Thanks!

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  • Vb.Net action delegate problem?

    - by Ramesh Vel
    Hi, Am vb.net newbie. This question might be very novice and answered before, but i couldn't find. I was trying the lambda features and got struck here. Private Function HigerOrderTest(highFunction as Func(Of Int16,Int16)) As Action(of String) Dim sam = highFunction(3) Dim DoIt as Action(of String) DoIt = sub(s) console.WriteLine(s) return DoIt End Function I got "Expression expected." at line DoIt = sub(s) console.WriteLine(s). And when i changed this to DoIt = function(s) console.WriteLine(s) i got Expression does not produce a value. error. Whats the problem? Cheers

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  • group by with 3 diffrent

    - by NN
    I have 2 table and I wanna a query with 3 column result in on of them 2 column with view count and title name and in the other 1 column with type_ and i wanna to grouping type_ with max(view count) and show the them title but i didn't have any idea about grouping expression. i think we can solve in by using sub query but i don't know which column use in group by. 2 table join with this expression class pk=resource key i exam this query: SELECT t.title,j.type_ FROM tags asset t,journal article j where type_ in (select type_ from journal article,tags asset where class pk=resource key group by type_) but the answer was wrong

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  • Using Nokogiri to scrape groupon deal

    - by hyngyn
    I'm following the Nokogiri railscast to write a scraper for Groupon. I keep on getting the following error when I run my rb file. traveldeal_scrape.rb:10: warning: regular expression has ']' without escape: /\[0-9 \.]+/ Flamingo Conference Resort and Spa Deal of the Day | Groupon Napa / Sonoma traveldeal_scrape.rb:9:in `block in <main>': undefined local variable or method `item' for main:Object (NameError) Here is my scrape file. require 'rubygems' require 'nokogiri' require 'open-uri' url = "http://www.groupon.com/deals/ga-flamingo-conferences-resort-spa?c=all&p=0" doc = Nokogiri::HTML(open(url)) puts doc.at_css("title").text doc.css(".deal").each do |deal| title = deal.at_css("#content//a").text price = deal.at_css("#amount").text[/\[0-9\.]+/] puts "#{title} - #{price}" puts deal.at_css(".deal")[:href] end I used the exact same rubular expression as the tutorial. I am also unsure of whether or not my CSS tags are correct. Thanks!

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  • algorithmes with no executable example code

    - by gcc
    [link] http://stackoverflow.com/questions/2932016/parsing-of-mathematical-expressions (problem has been told before) ** program is to create the infix tree for the given math expression.** if the expression is given completely paranthesized then the out put is fine but when there are no paranthesis or some part paranthesized then the out put is wrong. cant get the idea how to solve. my problem is told above. I have some algorithm to solve my problem, but I have no simple code which will be guide for me. Can anyone give me simple code (not working code) so that I will try working to understand.(for a 3 hours ,I have been searching and reading some text to understand algorithm which is told above.Actually,there is no example code investigating how it is working. Can anyone send me example which is written in c not other language.

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  • Extract IP address from an html string (python)

    - by GoJian
    My Friends, I really want to extract a simple IP address from a string (actually an one-line html) using Python. But it turns out that 2 hours passed I still couldn't come up with a good solution. >>> s = "<html><head><title>Current IP Check</title></head><body>Current IP Address: 165.91.15.131</body></html>" -- '165.91.15.131' is what I want! I tried using regular expression, but so far I can only get to the first number. >>> import re >>> ip = re.findall( r'([0-9]+)(?:\.[0-9]+){3}', s ) >>> ip ['165'] In fact, I don't feel I have a firm grasp on reg-expression and the above code was found and modified from elsewhere on the web. Seek your input and ideas!

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  • Access is refusing to run an query with linked table?

    - by Mahmoud
    Hey all i have 3 tables each as follow cash_credit Bank_Name-------in_date-------Com_Id---Amount America Bank 15/05/2010 1 200 HSBC 17/05/2010 3 500 Cheque_credit Bank_Name-----Cheque_Number-----in_date-------Com_Id---Amount America Bank 74835435-5435 15/05/2010 2 600 HSBC 41415454-2851 17/05/2010 5 100 Companies com_id----Com_Name 1 Ebay 2 Google 3 Facebook 4 Amazon Companies table is a linked table when i tried to create an query as follow SELECT cash_credit.Amount, Companies.Com_Name, cheque_credit.Amount FROM cheque_credit INNER JOIN (cash_credit INNER JOIN Companies ON cash_credit.com_id = Companies.com_id) ON cheque_credit.com_id = Companies.com_id; I get an error saying that my inner Join is incorrectly, this query was created using Access 2007 query design the error is Type mismatch in expression then i thought it might be the inner join so i tried Left Join and i get an error that this method is not used JOIN expression is not supported I am confused on where is the problem that is causing all this

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  • using NEWSEQUENTIALID() with UPDATE Trigger

    - by Ram
    I am adding a new GUID/Uniqueidentifier column to my table. ALTER TABLE table_name ADD VersionNumber UNIQUEIDENTIFIER UNIQUE NOT NULL DEFAULT NEWSEQUENTIALID() GO And when ever a record is updated in the table, I would want to update this column "VersionNumber". So I create a new trigger CREATE TRIGGER [DBO].[TR_TABLE_NAMWE] ON [DBO].[TABLE_NAME] AFTER UPDATE AS BEGIN UPDATE TABLE_NAME SET VERSIONNUMBER=NEWSEQUENTIALID() FROM TABLE_NAME D JOIN INSERTED I ON D.ID=I.ID/* some ID which is used to join*/ END GO But just realized that NEWSEQUENTIALID() can only be used with CREATE TABLE or ALTER TABLE. I got this error The newsequentialid() built-in function can only be used in a DEFAULT expression for a column of type 'uniqueidentifier' in a CREATE TABLE or ALTER TABLE statement. It cannot be combined with other operators to form a complex scalar expression. Is there a workaround for this ? Edit1: Changing NEWSEQUENTIALID() to NEWID() in the trigger solves this, but I am indexing this column and using NEWID() would be sub-optimal

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  • an error "variable of field declared void"

    - by lego69
    I have this code: header - test.h Inside header I have some class Z and definitions of two functions test and test2 I call function test2 from test void test2(Z z, Z const *za); this is implementation of the function: void test2(Z z, Z const *za){ int i = z; //this row works cout << i << endl; } I call it from test: test2(z1, za1); // za1 is pinter to object and z1 is some object but in my header I receive an 3 errors: Multiple markers at this line - initializer expression list treated as compound expression - `A' was not declared in this scope - variable or field `quiz2' declared void can somebody please explain why? thanks in advance

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  • Problem using Conditional Operation with Nullable Int

    - by Rajarshi
    A small problem. Any idea guys why this does not work? int? nullableIntVal = (this.Policy == null) ? null : 1; I am trying to return 'null' if the left hand expression is True, else 1. Seems simple but gives compilation error - Type of conditional expression cannot be determined because there is no implicit conversion between 'null' and 'int' If I replace the " ? null : 1 " with any valid int, then there is no problem.

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  • Regex in javascript for enum datatype of mysql

    - by himadri
    Hello, I am working with php and mysql. I have one dropdown box where I am asking datatype of mysql field. Now, I want to put javascript validation for it. I am confused with the enum datatype. I am using regular expression /^[']{1}[^',^\\]+[']{1}$/. This is for one single value of enum values. It is working fine but issue is when I put single quote or backslash with backslash, it is valid but this regular expression shows it as invalid. For eg, 'a'b' is invalid but 'a\'b' is valid.

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