Search Results

Search found 5819 results on 233 pages for 'compiler theory'.

Page 199/233 | < Previous Page | 195 196 197 198 199 200 201 202 203 204 205 206  | Next Page >

• How can I create an executable to run on a certain processor architecture (instead of certain OS)?

  - by CrazyJugglerDrummer

  So I take my C++ program in Visual studio, compile, and it'll spit out a nice little EXE file. But EXEs will only run on windows, and I hear a lot about how C/C++ compiles into assembly language, which is runs directly on a processor. The EXE runs with the help of windows, or I could have a program that makes an executable that runs on a mac. But aren't I compiling C++ code into assembly language, which is processor specific? My Insights: I'm guessing I'm probably not. I know there's an Intel C++ compiler, so would it make processor-specific assembly code? EXEs run on windows, so they advantage of tons of things already set up, from graphics packages to the massive .NET framework. A processor-specific executable would be literally starting from scratch, with just the instruction set of the processor. Would this executable be a file-type? We could be running windows and open it, but then would control switch to processor only? I assume this executable would be something like an operating system, in that it would have to be run before anything else was booted up, and have only the processor instruction set to "use".

  Read the article

• Adding items to a combo box's internal list programatically.

  - by Andrew

  So, despite Matt's generous explanation in my last question, I still didn't understand and decided to start a new project and use an internal list. - (void)applicationDidFinishLaunching:(NSNotification *)aNotification { codesList = [[NSString alloc] initWithContentsOfFile: @".../.../codelist.txt"]; namesList = [[NSString alloc] initWithContentsOfFile: @".../.../namelist.txt"]; codesListArray = [[NSMutableArray alloc]initWithArray:[codesList componentsSeparatedByString:@"\n"]]; namesListArray = [[NSMutableArray alloc]initWithArray:[namesList componentsSeparatedByString:@"\n"]]; addTheDash = [[NSString alloc]initWithString:@" - "]; flossNames = [[NSMutableArray alloc]init]; [flossNames removeAllObjects]; for (int n=0; n<=[codesListArray count]; n++){ NSMutableString *nameBuilder = [[NSMutableString alloc]initWithFormat:@"%@", [codesListArray objectAtIndex:n]]; [nameBuilder appendString:addTheDash]; [nameBuilder appendString:[namesListArray objectAtIndex:n]]; [comboBoz addItemWithObjectValue:[NSMutableString stringWithString:nameBuilder]]; [nameBuilder release]; } } So this is my latest attempt at this and the list still isn't showing in my combo box. I've tried using the addItemsWithObjectValues outside the for loop along with the suggestions at this question: Is this the right way to add items to NSCombobox in Cocoa ? But still no luck. If you can't tell, I'm trying to combine two strings from the files with a hyphen in between them and then put that new string into the combo box. There are over 400 codes and matching names in the two files, so manually putting them in would be a huge chore, not to mention, I don't see what would be causing this problem. The compiler shows no warnings or errors, and in the IB, I have it set to use the internal list, but when I run it, the list is not populated unless I do it manually. Some things I thought might be causing it: Being in the applicationDidFinishLaunching: method Having the string and array variables declared as instance variables in the header (along with @property and @synth done to them) Messing around with using appendString multiple times with NSMutableArrays Nothing seems to be causing this to me, but maybe someone else will know something I don't. Thanks for the help.

  Read the article

• Compile time float packing/punning

  - by detly

  I'm writing C for the PIC32MX, compiled with Microchip's PIC32 C compiler (based on GCC 3.4). My problem is this: I have some reprogrammable numeric data that is stored either on EEPROM or in the program flash of the chip. This means that when I want to store a float, I have to do some type punning: typedef union { int intval; float floatval; } IntFloat; unsigned int float_as_int(float fval) { IntFloat intf; intf.floatval = fval; return intf.intval; } // Stores an int of data in whatever storage we're using void StoreInt(unsigned int data, unsigned int address); void StoreFPVal(float data, unsigned int address) { StoreInt(float_as_int(data), address); } I also include default values as an array of compile time constants. For (unsigned) integer values this is trivial, I just use the integer literal. For floats, though, I have to use this Python snippet to convert them to their word representation to include them in the array: import struct hex(struct.unpack("I", struct.pack("f", float_value))[0]) ...and so my array of defaults has these indecipherable values like: const unsigned int DEFAULTS[] = { 0x00000001, // Some default integer value, 1 0x3C83126F, // Some default float value, 0.005 } (These actually take the form of X macro constructs, but that doesn't make a difference here.) Commenting is nice, but is there a better way? It's be great to be able to do something like: const unsigned int DEFAULTS[] = { 0x00000001, // Some default integer value, 1 COMPILE_TIME_CONVERT(0.005), // Some default float value, 0.005 } ...but I'm completely at a loss, and I don't even know if such a thing is possible. Notes Obviously "no, it isn't possible" is an acceptable answer if true. I'm not overly concerned about portability, so implementation defined behaviour is fine, undefined behaviour is not (I have the IDB appendix sitting in front of me). As fas as I'm aware, this needs to be a compile time conversion, since DEFAULTS is in the global scope. Please correct me if I'm wrong about this.

  Read the article

• C++ Beginner Delete Question

  - by Pooch

  Hi all, This is my first year learning C++ so bear with me. I am attempting to dynamically allocate memory to the heap and then delete the allocated memory. Below is the code that is giving me a hard time: // String.cpp #include "String.h" String::String() {} String::String(char* source) { this->Size = this->GetSize(source); this->CharArray = new char[this->Size + 1]; int i = 0; for (; i < this->Size; i++) this->CharArray[i] = source[i]; this->CharArray[i] = '\0'; } int String::GetSize(const char * source) { int i = 0; for (; source[i] != '\0'; i++); return i; } String::~String() { delete[] this->CharArray; } Here is the error I get when the compiler tries to delete the CharArray: 0xC0000005: Access violation reading location 0xccccccc0. And here is the last call on the stack: msvcr100d.dll!operator delete(void * pUserData) Line 52 + 0x3 bytes C++ I am fairly certain the error exists within this piece of code but will provide you with any other information needed. Oh yeah, using VS 2010 for XP. Thanks for any and all help!

  Read the article

• Porting - Shared Memory x32 & x64 processes

  - by dpb

  A 32 bit host Windows application setups shared memory (using memory mapped file / CreateFileMapping() API), and then other 32 bit client processes use this shared memory to communicate with each other. I am planning to port the host application to 64 bit platform and once it is ready, I intend that both 32 bit and 64 bit client processes should be able to use the shared memory setup by the main 64 bit host application. The original code written for host x32 application uses "size_t" almost everywhere, since this differs from 4 bytes to 8 bytes as we move from x32 to x64, I am looking for replacing it. I intend to replace "size_t" by "unsigned long long", so that its size will be same on 32 bit & 64 bit. Can you please suggest me better alternative? Also, will the use of "unsigned long long" have performance impact on x32 app .. i guess yes? Research Done - Found very useful articles - a) 20 issue in porting from 32 bit to 64 bit (www.viva64.com) b) No way to restrict/change "size_t" on x64 platform to 4 bytes using compiler flags or any hooks/crooks since it is typedef

  Read the article

• (x86) Assembler Optimization

  - by Pindatjuh

  I'm building a compiler/assembler/linker in Java for the x86-32 (IA32) processor targeting Windows. High-level concepts of a "language" (in essential a Java API for creating executables) are translated into opcodes, which then are wrapped and outputted to a file. The translation process has several phases, one is the translation between languages: the highest-level code is translated into the medium-level code which is then translated into the lowest-level code (probably more than 3 levels). My problem is the following; if I have higher-level code (X and Y) translated to lower-level code (x, y, U and V), then an example of such a translation is, in pseudo-code: x + U(f) // generated by X + V(f) + y // generated by Y (An easy example) where V is the opposite of U (compare with a stack push as U and a pop as V). This needs to be 'optimized' into: x + y (essentially removing the "useless" code) My idea was to use regular expressions. For the above case, it'll be a regular expression looking like this: x:(U(x)+V(x)):null, meaning for all x find U(x) followed by V(x) and replace by null. Imagine more complex regular expressions, for more complex optimizations. This should work on all levels. What do you suggest? What would be a good approach to optimize in these situations?

  Read the article

• Can I cross compile with gcc for an old version of a Linux distro on my Ubuntu 9.10?

  - by Johan

  Hi, I have some old hardware with an old version of say SuSE linux running on it. Now I have this fancy development machine running Ubuntu 9.10. Some of the tools I use to compile my C app (written in Python 2.6.x) are not available on the old SuSe box. So... is it possible to compile for that old machine on my dev box? I have the following steps in mind, but would like to cross-check before venturing off into this quest: 1. Find out which static/shared libs my app needs and find/build target version of them 2. Also find the corresponding header files 3. Feed the correct flags to gcc to use the target headers and libraries 4. Feed the correct flags to gcc to use the correct architecture (i386/i686), or do I need a cross-compilation toolchain. 5. Compile, upload and enjoy ;-) I regularly use avr-gcc and cc65, both are cross compiling. I know that you set up a coss compiler for developing something like a gumstix, so it should be possible to do the same for old/other Linux distros, not? C

  Read the article

• can not override showDialog in Activity tab

  - by hornetbzz

  Trying to downgrade my appl from android 2.2 (API 8) down to android 2.1 (API7), I'm facing some issues with dialog boxes. Based on this thread, I'm trying to catch these exceptions but can't override the showDialog method. I turned the Java compiler from 1.5 to 1.6 according to this answer to a similar issue, but no changes, Eclipse still returns : Cannot override the final method from Activity public class MyActivity extends Activity implements SeekBar.OnSeekBarChangeListener { // ... some stuffs @Override // here is the issue public void showDialog(int dialogId) { try { super.showDialog(dialogId); } catch (IllegalArgumentException e) { Log.e(ACTIVITY_TAG, "Error dialog"); } } @Override protected Dialog onCreateDialog(int id) { switch (id) { case DIALOG_ALERT: // Create out AlertDialog Builder builder = new AlertDialog.Builder(this); builder.setMessage(msg); builder.setCancelable(false); builder.setPositiveButton(GOTO_BOOK, new OkOnClickListener()); builder.setNegativeButton(STAY_HERE, new CancelOnClickListener()); AlertDialog dialog = builder.create(); dialog.show(); break; case DIALOG_ONCREATE: // Create out AlertDialog during the "onCreate" method (only "Ok" // button) Builder builder2 = new AlertDialog.Builder(getParent()); builder2.setMessage(msg); builder2.setCancelable(false); builder2.setPositiveButton(GO_BACK, new OkOnClickListener()); AlertDialog dialog2 = builder2.create(); dialog2.show(); break; } return super.onCreateDialog(id); } // ... some stuffs }

  Read the article

• RegisterStartupScript not working after upgrading to framework 3.5

  - by AaronS

  I'm trying to upgrade an asp.net c# web project from framework 2.0 to 3.5. When I do this, the client side script that gets written using RegisterStartupScript isn't rendered on the client page. This works perfectly when I compile for 2.0, and for 3.0, but not when I compile for 3.5. Here is the code that isn't getting rendered: Page myPage = (Page)HttpContext.Current.Handler; ScriptManager.RegisterStartupScript(myPage, myPage.GetType(), "alertscript", "alert('test');", true); This is called from a class project, and not the web project itself, which is why I'm using the HttpContext.Current.Handler. There are no errors getting generated from the compiler, the CLR, and there are no client side JavaScript errors. If I do a search for the "alertscript" in my rendered page, the above code actually isn't there. Anyone have ideas as to what is going on? -Edit- This seems to be an issue when I'm trying to register the script from an external project. If I use the exact same code in a class file in the web project (not the code behind), it works. However, if I make a call to a method in a class from another project, it does not work. Does the ScriptManager.RegisterStartupScript not get registered correctly if performed from somewhere besides the web project itself?

  Read the article

• A monkey could do this better - Access to and availability of private member functions in C++

  - by David

  I am wandering the desert of my brain. I'm trying to write something like the following: class MyClass { // Peripherally Related Stuff public: void TakeAnAction(int oneThing, int anotherThing) { switch(oneThing){ case THING_A: TakeThisActionWith(anotherThing); break; //cases THINGS_NOT_A: }; private: void TakeThisActionWith(int thing) { string outcome = new string; outcome = LookUpOutcome(thing); // Do some stuff based on outcome return; } string LookUpOutcome(int key) { string oc = new string; oc = MyPrivateMap[key]; return oc; } map<int, string> MyPrivateMap; Then in the .cc file where I am actually using these things, while compiling the TakeAnAction section, it [CC, the solaris compiler] throws an an error: 'The function LookUpOutcome must have a prototype' and bombs out. In my header file, I have declared 'string LookUpOutcome(int key);' in the private section of the class. I have tried all sorts of variations. I tried to use 'this' for a little while, and it gave me 'Can only use this in non-static member function.' Sadly, I haven't declared anything static and these are all, putatively, member functions. I tried it [on TakeAnAction and LookUp] when I got the error, but I got something like, 'Can't access MyPrivateMap from LookUp'. MyPrivateMap could be made public and I could refer to it directly, I guess, but my sensibility says that is not the right way to go about this [that means that namespace scoped helper functions are out, I think]. I also guess I could just inline the lookup and subsequent other stuff, but my line-o-meter goes on tilt. I'm trying desperately not to kludge it.

  Read the article

• 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?

  Read the article

• How to pass a Dictionary variable to another procedure

  - by salvationishere

  I am developing a C# VS2008/SQL Server website application. I've never used the Dictionary class before, but I am trying to replace my Hashtable with a Dictionary variable. Here is a portion of my aspx.cs code: ... Dictionary<string, string> openWith = new Dictionary<string, string>(); for (int col = 0; col < headers.Length; col++) { @temp = (col + 1); @tempS = @temp.ToString(); @tempT = "@col" + @temp.ToString(); ... openWith.Add(@tempT, headers[col]); } ... for (int r = 0; r < myInputFile.Rows.Count; r++) { resultLabel.Text = ADONET_methods.AppendDataCT(myInputFile, openWith); } But this is giving me a compiler error on this last line: Argument '2': cannot convert from 'System.Collections.Generic.Dictionary' to 'string' How do I pass the entire openWith variable to AppendDataCT? AppendDataCT is the method that calls my SQL stored proc. I want to pass in the whole row where each row has a unique set of values that I want to add to my database table. For example, if each row requires values for cells A, B, and C, then I want to pass these 3 values to AppendDataCT, where all of these values are strings. How do I do this with Dictionary?

  Read the article

• Strange Behaviour in Swift: constant defined with LET but behaving like a variable defined with VAR

  - by Sam

  Stuck on the below for a day! Any insight would be greatly appreciated. The constant in the first block match0 behaves as expected. The constant defined in the second block does not behave as nicely in the face of a change to its "source": var str = "+y+z*1.0*sum(A1:A3)" if let range0 = str.rangeOfString("^\\+|^\\-|^\\*|^\\/", options: NSStringCompareOptions.RegularExpressionSearch){ let match0 = str[range0] println(match0) //yields "+" - as expexted str.removeRange(range0) println(match0) //yields "+" - as expected str.removeRange(range0) println(match0) //yields "+" - as expected } if let range1 = str.rangeOfString("^\\+|^\\-|^\\*|^\\/", options: NSStringCompareOptions.RegularExpressionSearch){ let match1 = str[range1] println(match1) //yields "+" as expected str.removeRange(range1) println(match1) //!@#$ OMG!!!!!!!!!!! a constant variable has changed! This prints "z" } The following are the options I can see: match1 has somehow obtained a reference to its source instead of being copied by value [Problem: Strings are value types in Swift] match1 has somehow obtained a closure to its source instead of just being a normal constant/variable? [Problem: sounds like science fiction & then why does match0 behave so well?] Could there be a bug in the Swift compiler? [Problem: Experience has taught me that this is very very very rarely the solution to your problem...but it is still in beta]

  Read the article

• VB.NET switching from ADO.NET to LINQ

  - by Cj Anderson

  I'm VERY new to Linq. I have an application I wrote that is in VB.NET 2.0. Works great, but I'd like to switch this application to Linq. I use ADO.NET to load XML into a datatable. The XML file has about 90,000 records in it. I then use the Datatable.Select to perform searches against that Datatable. The search control is a free form textbox. So if the user types in terms it searches instantly. Any further terms that are typed in continue to restrict the results. So you can type in Bob, or type in Bob Barker. Or type in Bob Barker Price is Right. The more criteria typed in the more narrowed your result. I bind the results to a gridview. Moving forward what all do I need to do? From a high level, I assume I need to: 1) Go to Project Properties -- Advanced Compiler Settings and change the Target framework to 3.5 from 2.0. 2) Add the reference to System.XML.Linq, Add the Imports statement to the classes. So I'm not sure what the best approach is going forward after that. I assume I use XDocument.Load, then my search subroutine runs against the XDocument. Do I just do the standard Linq query for this sort of repeated search? Like so: var people = from phonebook in doc.Root.Elements("phonebook") where phonebook.Element("userid") = "whatever" select phonebook; Any tips on how to best implement?

  Read the article

• Instantiating and starting a Scala Actor in a Map

  - by Bruce Ferguson

  I'm experimenting with a map of actors, and would like to know how to instantiate them and start them in one fell swoop... import scala.actors.Actor import scala.actors.Actor._ import scala.collection.mutable._ abstract class Message case class Update extends Message object Test { val groupings = "group1" :: "group2" :: "group3":: Nil val myActorMap = new HashMap[String,MyActor] def main(args : Array[String]) { groupings.foreach(group => myActorMap += (group -> new MyActor)) myActorMap("group2").start myActorMap("group2") ! Update } } class MyActor extends Actor { def act() { loop { react { case Update => println("Received Update") case _ => println("Ignoring event") } } } } The line: myActorMap("group2").start will grab the second instance, and let me start it, but I would like to be able to do something more like: groupings.foreach(group => myActorMap += (group -> (new MyActor).start)) but no matter how I wrap the new Actor, the compiler complains with something along the lines of: type mismatch; found : scala.actors.Actor required: com.myCompany.test.MyActor or various other complaints. I know it must be something simple to do with anonymous classes, but I can't see it right now. Any suggestions? Thanks in advance!!

  Read the article

• Potential g++ template bug?

  - by Evan Teran

  I've encountered some code which I think should compile, but doesn't. So I'm hoping some of the local standards experts here at SO can help :-). I basically have some code which resembles this: #include <iostream> template <class T = int> class A { public: class U { }; public: U f() const { return U(); } }; // test either the work around or the code I want... #ifndef USE_FIX template <class T> bool operator==(const typename A<T>::U &x, int y) { return true; } #else typedef A<int> AI; bool operator==(const AI::U &x, int y) { return true; } #endif int main() { A<int> a; std::cout << (a.f() == 1) << std::endl; } So, to describe what is going on here. I have a class template (A) which has an internal class (U) and at least one member function which can return an instance of that internal class (f()). Then I am attempting to create an operator== function which compares this internal type to some other type (in this case an int, but it doesn't seem to matter). When USE_FIX is not defined I get the following error: test.cc: In function 'int main()': test.cc:27:25: error: no match for 'operator==' in 'a.A<T>::f [with T = int]() == 1' Which seems odd, because I am clearly (I think) defining a templated operator== which should cover this, in fact if I just do a little of the work for the compiler (enable USE_FIX), then I no longer get an error. Unfortunately, the "fix" doesn't work generically, only for a specific instantiation of the template. Is this supposed to work as I expected? Or is this simply not allowed? BTW: if it matters I am using gcc 4.5.2.

  Read the article

• Why are virtual methods considered early bound?

  - by AspOnMyNet

  One definition of binding is that it is the act of replacing function names with memory addresses. a) Thus I assume early binding means function calls are replaced with memory addresses during compilation process, while with late binding this replacement happens during runtime? b) Why are virtual methods also considered early bound (thus the target method is found at compile time, and code is created that will call this method)? As far as I know, with virtual methods the call to actual method is resolved only during runtime and not compile time?! thanx EDIT: 1) A a=new A(); a.M(); As far as I know, it is not known at compile time where on the heap (thus at which memory address ) will instance a be created during runtime. Now, with early binding the function calls are replaced with memory addresses during compilation process. But how can compiler replace function call with memory address, if it doesn’t know where on the heap will object a be created during runtime ( here I’m assuming the address of method a.M will also be at same memory location as a )? 2) v-table calls are neither early nor late bound. Instead there's an offset into a table of function pointers. The offset is fixed at compile time, but which table the function pointer is chosen from depends on the runtime type of the object (the object contains a hidden pointer to its v-table), so the final function address is found at runtime. But assuming the object of type T is created via reflection ( thus app doesn’t even know of existence of type T ), then how can at compile time exist an entry point for that type of object?

  Read the article

• Please take a stab at this VB.Net Oracle-related sample and help me with String.Format.

  - by Hamish Grubijan

  If the database is not Oracle, it is MS SQl 2008. My task: if Oracle, add two more parameters when calling a stored proc. Oracle and MSFT stored procs are generated; Oracle ones have 3 extra parameters: Vret_val out number, Vparam2 in out number, Vparam3 in out number, ... the rest (The are not actually named Vparam2 and Vparam3, but this should not matter). So, the code for a helper VB.Net class that calls a stored proc: Imports System.Data.Odbc Imports System.Configuration Dim objCon As OdbcConnection = Nothing Dim objAdapter As OdbcDataAdapter Dim cmdCommand As New OdbcCommand Dim objDataTable As DataTable Dim sconnection As String Try sconnection = mConnectionString objAdapter = New OdbcDataAdapter objCon = New OdbcConnection(sconnection) objCon.Open() objAdapter.SelectCommand = cmdCommand objAdapter.SelectCommand.Connection = objCon objAdapter.SelectCommand.CommandType = CommandType.StoredProcedure objAdapter.SelectCommand.CommandTimeout = Globals.mReportTimeOut If Not mIsOracle Then objAdapter.SelectCommand.CommandText = String.Format("{{call {0}}}", spName) Else Dim returnValue As New OdbcParameter returnValue.Direction = ParameterDirection.Output returnValue.ParameterName = "@Vret_val" returnValue.OdbcType = OdbcType.Numeric objAdapter.SelectCommand.Parameters.Add(returnValue) objAdapter.SelectCommand.CommandText = String.Format("{{call {0}(?)}}", spName) End If Try objDataTable = New DataTable(spName) objAdapter.Fill(objDataTable) Catch ex As Exception ... Question: I am puzzled as to what String.Format("{{call {0}(?)}}", spName) does, in particular the (?) part. My understanding of the String.Format is that it will simply replace {0} with spName. The {{, }}, and (?) do throw me off because { reminds me of formatting, (?) hints at some advanced regex use. Unfortunately I am getting little help from a key person who is on vacation without a leash [smart]phone. I am guessing that I simply add 5 more lines for each additional parameter, and change String.Format("{{call {0}(?)}}", spName) to String.Format("{{call {0}(?,?,?)}}", spName). I forgot to mention that I am coding this "blindly" - I have a compiler to help me, but no environment set up to test this. This will be over in a few days, but I need to do my best to try finishing it on time :) Thanks.

  Read the article

• C/C++ Control Structure Limitations?

  - by STingRaySC

  I have heard of a limitation in VC++ (not sure which version) on the number of nested if statements (somewhere in the ballpark of 300). The code was of the form: if (a) ... else if (b) ... else if (c) ... ... I was surprised to find out there is a limit to this sort of thing, and that the limit is so small. I'm not looking for comments about coding practice and why to avoid this sort of thing altogether. Here's a list of things that I'd imagine could have some limitation: Number of functions in a scope (global, class, or namespace). Number of expressions in a single statement (e.g., compound conditionals). Number of cases in a switch. Number of parameters to a function. Number of classes in a single hierarchy (either inheritance or containment). What other control structures/language features have limits such as this? Do the language standards say anything about these limits (perhaps minimum requirements for an implementation)? Has anyone run into a particular language limitation like this with a particular compiler/implementation? EDIT: Please note that the above form of if statements is indeed "nested." It is equivalent to: if (a) { //... } else { if (b) { //... } else { if (c) { //... } else { //... } } }

  Read the article

• Closures and universal quantification

  - by Apocalisp

  I've been trying to work out how to implement Church-encoded data types in Scala. It seems that it requires rank-n types since you would need a first-class const function of type forAll a. a -> (forAll b. b -> b). However, I was able to encode pairs thusly: import scalaz._ trait Compose[F[_],G[_]] { type Apply = F[G[A]] } trait Closure[F[_],G[_]] { def apply[B](f: F[B]): G[B] } def pair[A,B](a: A, b: B) = new Closure[Compose[PartialApply1Of2[Function1,A]#Apply, PartialApply1Of2[Function1,B]#Apply]#Apply, Identity] { def apply[C](f: A => B => C) = f(a)(b) } For lists, I was able to get encode cons: def cons[A](x: A) = { type T[B] = B => (A => B => B) => B new Closure[T,T] { def apply[B](xs: T[B]) = (b: B) => (f: A => B => B) => f(x)(xs(b)(f)) } } However, the empty list is more problematic and I've not been able to get the Scala compiler to unify the types. Can you define nil, so that, given the definition above, the following compiles? cons(1)(cons(2)(cons(3)(nil)))

  Read the article

• ASP.NET web setup class is not defined

  - by Wayne Werner

  Hi, I've got an ASP.NET application that I installed by creating a web setup. I ran into a problem where ASP.NET wasn't registered with IIS so it gave me a "installation was interrupted" message that told me exactly nothing. Anyhow, I finally got it installed, and I can access the main page, but it's telling me that my class isn't defined. The dll is in the same directory as the Default.aspx page Here's the main error information Compiler Error Message: BC30002: Type 'SIValidator.SIValidator' is not defined. Source Error: Line 4: Line 5: <script runat="server"> Line 6: Dim validator As New SIValidator.SIValidator() Line 7: Protected table As New arrayList() Line 8: Protected countyByDistrict As New Hashtable() Version Information: Microsoft .NET Framework Version:2.0.50727.1873; ASP.NET Version:2.0.50727.1433 Am I doing it wrong? Is there some obscure setting that may not be set? I'm completely new to this VS deployment deal, so I'm trying to learn the right terms to ask the right questions... Thanks for any help edit: As an aside, when I searched google 5 minutes later, this entry came up as the first result. Would have been awesome if there was an answer for me then :P

  Read the article

• Constructor or Assignment Operator

  - by ju

  Can you help me is there definition in C++ standard that describes which one will be called constructor or assignment operator in this case: #include <iostream> using namespace std; class CTest { public: CTest() : m_nTest(0) { cout << "Default constructor" << endl; } CTest(int a) : m_nTest(a) { cout << "Int constructor" << endl; } CTest(const CTest& obj) { m_nTest = obj.m_nTest; cout << "Copy constructor" << endl; } CTest& operatorint rhs) { m_nTest = rhs; cout << "Assignment" << endl; return *this; } protected: int m_nTest; }; int _tmain(int argc, _TCHAR* argv[]) { CTest b = 5; return 0; } Or is it just a matter of compiler optimization?

  Read the article

• Function parameters evaluation order: is undefined behaviour if we pass reference?

  - by bolov

  This is undefined behaviour: void feedMeValue(int x, int a) { cout << x << " " << a << endl; } int main() { int a = 2; int &ra = a; feedMeValue(ra = 3, a); return 0; } because depending on what parameter gets evaluated first we could call (3, 2) or (3, 3). However this: void feedMeReference(int x, int const &ref) { cout << x << " " << ref << endl; } int main() { int a = 2; int &ra = a; feedMeReference(ra = 3, a); return 0; } will always output 3 3 since the second parameter is a reference and all parameters have been evaluated before the function call, so even if the second parameter is evaluated before of after ra = 3, the function received a reference to a wich will have a value of 2 or 3 at the time of the evaluation, but will always have the value 3 at the time of the function call. Is the second example UB? It is important to know because the compiler is free to do anything if he detects undefined behaviour, even if I know it would always yield the same results. *Note: I think that feedMeReference(a = 3, a) is the exact same situation as feedMeReference(ra = 3, a). However it seems not everybody agrees, in the addition to having 2 completely different answers.

  Read the article

• Compiling Objective-C project on Linux (Ubuntu)

  - by Alex

  How to make an Objective-C project work on Ubuntu? My files are: Fraction.h #import <Foundation/NSObject.h> @interface Fraction: NSObject { int numerator; int denominator; } -(void) print; -(void) setNumerator: (int) n; -(void) setDenominator: (int) d; -(int) numerator; -(int) denominator; @end Fraction.m #import "Fraction.h" #import <stdio.h> @implementation Fraction -(void) print { printf( "%i/%i", numerator, denominator ); } -(void) setNumerator: (int) n { numerator = n; } -(void) setDenominator: (int) d { denominator = d; } -(int) denominator { return denominator; } -(int) numerator { return numerator; } @end main.m #import <stdio.h> #import "Fraction.h" int main( int argc, const char *argv[] ) { // create a new instance Fraction *frac = [[Fraction alloc] init]; // set the values [frac setNumerator: 1]; [frac setDenominator: 3]; // print it printf( "The fraction is: " ); [frac print]; printf( "\n" ); // free memory [frac release]; return 0; } I've tried two approaches to compile it: Pure gcc: $ sudo apt-get install gobjc gnustep gnustep-devel $ gcc `gnustep-config --objc-flags` -o main main.m -lobjc -lgnustep-base /tmp/ccIQKhfH.o:(.data.rel+0x0): undefined reference to `__objc_class_name_Fraction' I created a GNUmakefile Makefile: include ${GNUSTEP_MAKEFILES}/common.make TOOL_NAME = main main_OBJC_FILES = main.m include ${GNUSTEP_MAKEFILES}/tool.make ... and ran: $ source /usr/share/GNUstep/Makefiles/GNUstep.sh $ make Making all for tool main... Linking tool main ... ./obj/main.o:(.data.rel+0x0): undefined reference to `__objc_class_name_Fraction' So in both cases compiler gets stuck at undefined reference to `__objc_class_name_Fraction' Do you have and idea how to resolve this issue?

  Read the article

• Why do case class companion objects extend FunctionN?

  - by retronym

  When you create a case class, the compiler creates a corresponding companion object with a few of the case class goodies: an apply factory method matching the primary constructor, equals, hashCode, and copy. Somewhat oddly, this generated object extends FunctionN. scala> case class A(a: Int) defined class A scala> A: (Int => A) res0: (Int) => A = <function1> This is only the case if: There is no manually defined companion object There is exactly one parameter list There are no type arguments The case class isn't abstract. Seems like this was added about two years ago. The latest incarnation is here. Does anyone use this, or know why it was added? It increases the size of the generated bytecode a little with static forwarder methods, and shows up in the #toString() method of the companion objects: scala> case class A() defined class A scala> A.toString res12: java.lang.String = <function0>

  Read the article

< Previous Page | 195 196 197 198 199 200 201 202 203 204 205 206  | Next Page >