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  • Which syntax is better for return value?

    - by Omar Kooheji
    I've been doing a massive code review and one pattern I notice all over the place is this: public bool MethodName() { bool returnValue = false; if (expression) { // do something returnValue = MethodCall(); } else { // do something else returnValue = Expression; } return returnValue; } This is not how I would have done this I would have just returned the value when I knew what it was. which of these two patterns is more correct? I stress that the logic always seems to be structured such that the return value is assigned in one plave only and no code is executed after it's assigned.

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  • Why does one of these statements compile in Scala but not the other?

    - by Jeff
    (Note: I'm using Scala 2.7.7 here, not 2.8). I'm doing something pretty simple -- creating a map based on the values in a simple, 2-column CSV file -- and I've completed it easily enough, but I'm perplexed at why my first attempt didn't compile. Here's the code: // Returns Iterator[String] private def getLines = Source.fromFile(csvFilePath).getLines // This doesn't compile: def mapping: Map[String,String] = { Map(getLines map { line: String => val pairArr = line.split(",") pairArr(0) -> pairArr(1).trim() }.toList:_*) } // This DOES compile def mapping: Map[String,String] = { def strPair(line: String): (String,String) = { val pairArr = line.split(",") pairArr(0) -> pairArr(1).trim() } Map(getLines.map( strPair(_) ).toList:_*) } The compiler error is CsvReader.scala:16: error: value toList is not a member of (St ring) = (java.lang.String, java.lang.String) [scalac] possible cause: maybe a semicolon is missing before `value toList'? [scalac] }.toList:_*) [scalac] ^ [scalac] one error found So what gives? They seem like they should be equivalent to me, apart from the explicit function definition (vs. anonymous in the nonworking example) and () vs. {}. If I replace the curly braces with parentheses in the nonworking example, the error is "';' expected, but 'val' found." But if I remove the local variable definition and split the string twice AND use parens instead of curly braces, it compiles. Can someone explain this difference to me, preferably with a link to Scala docs explaining the difference between parens and curly braces when used to surround method arguments?

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  • Ruby: change each value in a hash with something like #collect for arrays?

    - by Adam Nonymous
    Hi! I'd like to replace each value in a hash with value.some_method. For example in a simple hash {"a" = "b", "c" = "d"} every value should be .upcase-d so it looks like {"a" = "B", "c" = "D"}. I tried #collect and #map but always just get arrays back. Is there an 'elegant' way to do this? Thanks in advance, Adam Nonymous UPDATE: Damn, I forgot: The hash is in an instance variable which should not be changed. I need a new hash with the changed values, but would prefer not to define that variable explicitly and then loop over the hash filling it. Something like new_hash = hash.magic {...} ;)

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  • What does the '&' operator do in C++?

    - by rascher
    n00b question. I am a C guy and I'm trying to understand some C++ code. I have the following function declaration: int foo(const string &myname) { cout << "called foo for: " << myname << endl; return 0; } How does the function signature differ from the equivalent C: int foo(const char *myname) Is there a difference between using string *myname vs string &myname? What is the difference between & in C++ and * in C to indicate pointers? Similarly: const string &GetMethodName() { ... } What is the & doing here? Is there some website that explains how & is used differently in C vs C++?

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  • What is the form_for syntax for nested resources?

    - by Kris
    I am trying to create a form for a nested resource. Here is my route: map.resources :websites do |website| website.resources :domains end Here are my attempts and the errors: <% form_for(@domain, :url => website_domains_path(@website)) do | form | %> <%= form.text_field :name %> # ArgumentError: wrong number of arguments (1 for 0) # form_helper.rb:290:in 'respond_to?' # form_helper.rb:290:in 'apply_form_for_options!' # form_helper.rb:277:in 'form_for' <% form_for([@website, @domain]) do | form | %> <%= form.text_field :name %> # ArgumentError: wrong number of arguments (1 for 0) # form_helper.rb:290:in 'respond_to?' # form_helper.rb:290:in 'apply_form_for_options!' # form_helper.rb:277:in 'form_for' <% form_for(:domain, @domain, :url => website_domains_path(@website)) do | form | %> <%= form.text_field :name %> # ArgumentError: wrong number of arguments (1 for 0) # wrapper.rb:14:in 'respond_to?' # wrapper.rb:14:in 'wrap' # active_record_helper.rb:174:in 'error_messages_for' <% form_for(:domain, [@website, @domain]) do | form | %> <%= form.text_field :name %> # UndefinedMethodError 'name' for #<Array:0x40fa498> I have confirmed both @website and @domain contain instances of the correct class. The routes also generate correctly is used like this for example, so I dont think their is an issue with the route or url helpers. <%= website_domains_path(1) %> <%= website_data_source_path(1, 1) %> Rails 2.3.5

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  • Python: needs more than 1 value to unpack

    - by Rosarch
    What am I doing wrong to get this error? replacements = {} replacements["**"] = ("<strong>", "</strong>") replacements["__"] = ("<em>", "</em>") replacements["--"] = ("<blink>", "</blink>") replacements["=="] = ("<marquee>", "</marquee>") replacements["@@"] = ("<code>", "</code>") for delimiter, (open_tag, close_tag) in replacements: # error here message = self.replaceFormatting(delimiter, message, open_tag, close_tag); The error: Traceback (most recent call last): File "", line 1, in for shit, (a, b) in replacements: ValueError: need more than 1 value to unpack All the values tuples have two values. Right?

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  • Inline HTML Syntax for Helpers in ASP.NET MVC

    - by kouPhax
    I have a class that extends the HtmlHelper in MVC and allows me to use the builder pattern to construct special output e.g. <%= Html.FieldBuilder<MyModel>(builder => { builder.Field(model => model.PropertyOne); builder.Field(model => model.PropertyTwo); builder.Field(model => model.PropertyThree); }) %> Which outputs some application specific HTML, lets just say, <ul> <li>PropertyOne: 12</li> <li>PropertyTwo: Test</li> <li>PropertyThree: true</li> </ul> What I would like to do, however, is add a new builder methid for defining some inline HTML without having to store is as a string. E.g. I'd like to do this. <% Html.FieldBuilder<MyModel>(builder => { builder.Field(model => model.PropertyOne); builder.Field(model => model.PropertyTwo); builder.ActionField(model => %> Generated: <%=DateTime.Now.ToShortDate()%> (<a href="#">Refresh</a>) <%); }).Render(); %> and generate this <ul> <li>PropertyOne: 12</li> <li>PropertyTwo: Test</li> <li>Generated: 29/12/2008 <a href="#">Refresh</a></li> </ul> Essentially an ActionExpression that accepts a block of HTML. However to do this it seems I need to execute the expression but point the execution of the block to my own StringWriter and I am not sure how to do this. Can anyone advise?

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  • VBA: Difference in two ways of declaring a new object? (Trying to understand why my solution works)

    - by Matt
    I was creating a new object within a loop, and adding that object to a collection; but when I read back the collection after, it was always filled entirely with the last object I had added. I've come up with two ways around this, but I simply do not understand why my initial implementation was wrong. Original: Dim oItem As Variant Dim sOutput As String Dim i As Integer Dim oCollection As New Collection For i = 0 To 10 Dim oMatch As New clsMatch oMatch.setLineNumber i oCollection.Add oMatch Next For Each oItem In oCollection sOutput = sOutput & "[" & oItem.lineNumber & "]" Next MsgBox sOutput This resulted in every lineNumber being 10; I was obviously not creating new objects, but instead using the same one each time through the loop, despite the declaration being inside of the loop. So, I added Set oMatch = Nothing immediately before the Next line, and this fixed the problem, it was now 0 to 10. So if the old object was explicitly destroyed, then it was willing to create a new one? I would have thought the next iteration through the loop would cause anything declared within the loop do be destroyed due to scope? Curious, I tried another way of declaring a new object: Dim oMatch As clsMatch: Set oMatch = New clsMatch. This, too, results in 0 to 10. Can anyone explain to me why the first implementation was wrong?

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  • how to modify this jquery syntax

    - by Gandalf StormCrow
    Hi all, this example below works when hover event is trigered and when its not, its working for elements already in DOM, but when element created dynamically it doesn't work, I realize I need to use jQuery live() or delegate() for this, the thing is I tried to modify it and its not producing the results as expected, here is the working code : $(".sidebar li").hover( function(){ $(this).css("background-color", "#F9F4D0"); $(this).append($('<button class="promoter" type="button" title="Active promotion"></button>')); }, function(){ $(this).css("background-color", "#F9FAFA"); $(this).children("button").remove(); } ); Here is the bit when I wanted to add live but it's not producing correct results : $(".sidebar li").live('hover', function(){ $(this).css("background-color", "#F9F4D0"); $(this).append($('<button class="promoter" type="button" title="Active promotion"></button>')); }, function(){ $(this).css("background-color", "#F9FAFA"); $(this).children("button").remove(); } ); Where did I made mistake, thank you

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  • C++: Unknown pointer size when forward declaring (error C2036)

    - by Rosarch
    In a header file, I have forward declared two members of a namespace: namespace Foo { struct Odp typedef std::vector<Odp> ODPVEC; }; class Bar { public: Foo::ODPVEC baz; // C2036 }; The error generated by the compiler is: error C2036: 'Foo::Odp *': unknown size I'm guessing this is an issue with forward declaring Odp. How can I get around this?

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  • Code doesn't work in foreach

    - by Arlen Beiler
    Here is my code: var divarray = document.getElementById("yui-main").getElementsByTagName("div"); var articleHTML; var absHTML; var keyHTML; var bodyHTML = []; for( var i in divarray) { if(divarray[i].className == "articleBody"){ articleHTML = divarray[i]; for( var j in articleHTML ){ bodyHTML[i] = ''; if(articleHTML[j].className == "issueMiniFeature"){continue;} if(articleHTML[j].className == "abstract"){absHTML = articleHTML[i]; continue;} if(articleHTML[j].className == "journalKeywords"){keyHTML = articleHTML[i]; continue;} bodyHTML[i] = articleHTML[i]; } break; } i++; } The error I am getting is: SyntaxError: Unexpected token var I am using Google Chrome

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  • Is Odersky serious with "bills !*&^%~ code!" ?

    - by stacker
    In his book programming in scala (Chapter 5 Section 5.9 Pg 93) Odersky mentioned this expression "bills !*&^%~ code! In the footnote on same page: "By now you should be able to figure out that given this code,the Scala compiler would invoke (bills.!*&^%~(code)).!()." That's a bit to cryptic for me, could someone explain what's going on here?

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  • What is wrong with this null check for data reader

    - by Phil
    c.Open() r = x.ExecuteReader If Not r("filename").IsDbnull Then imagepath = "<img src='images/'" & getimage(r("filename")) & " border='0' align='absmiddle'" End If c.Close() r.Close() I have also tried; If r("filename") Is DBNull.Value Then imagepath = String.Empty Else imagepath = "<img src='images/'" & getimage(r("filename")) & " border='0' align='absmiddle'" End If c.Close() r.Close() The error is: Invalid attempt to read when no data is present. The idea of my code is to build an img src string only when data is available. Help greatly appreciated. Thanks

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  • Pascal's repeat... until vs. C's do... while

    - by Bob
    In C there is a do while loop and pascal's (almost) equivalent is the repeat until loop, but there is a small difference between the two, while both structures will iterate at least once and check whether they need to do the loop again only in the end, in pascal you write the condition that need to met to terminate the loop (REPEAT UNTIL something) in C you write the condition that need to be met to continue the loop (DO WHILE something). Is there a reason why there is this difference or is it just an arbitrary decision?

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  • Initialisation of Objects Syntax question

    - by Brock Woolf
    When I initialise a struct in C (Node is the struct): struct Node { /* Non-Relevant code */ }; This works: Node *rootNode = new Node(); but so does this: Node *rootNode = new Node; Is there a difference, and what is the difference between using () or not using the brackets? Just off memory, I think the same applies above for C++ object initialisations. What is happening here?

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  • HOw I can verify my SQL / SQL Pl syntax

    - by rima
    Hi all Sorry my English is bad.I hope u can get what I want. I have lots of *.sql files that i want to write a program to compile them and if there is any issue(problem or mistake) report me. One of my friend write an IDE for java,as I remember he use javac to generate the codes error,in other hand maybe u see when u try to write code in a Visual stadio or Netbean the IDE generate errors for u.so now I want to know any one have any idea how I can do it for my sql files? In other mean I want to write a Editor for SQL files(PL/SQL) that compile my code and tell me what is my error. this problem raise up when I try to compile all of them in SQL PLUS,it's so boring. please help me...

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