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  • Using MonadPlus in FRP.Reactive.FieldTrip

    - by ony
    I'm studying FRP at this moment through FieldTrip adaptor. And hit the problem with strange way of frames scheduling and integration. So now I'm trying to build own marker Event for aligning Behaviour stepping. So... flipflop :: Behavior String flipflop = stepper "none" (xflip 2) where xflip t0 = do t <- withTimeE_ (atTime t0) return "flip" `mplus` xflop (t+3) xflop t0 = do t <- withTimeE_ (atTime t0) return "flop" `mplus` xflip (t+2) txtGeom = ((uscale2 (0.5::Float) *%) . utext . show <$>) main = anim2 (txtGeom . pure flipflop) Questions is: Why this example leads to memory leak? Is there safe way to build sequence of events where each next one is scheduled depending on previous?

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  • simple putStrLn in Haskell/Yampa with arrows syntax

    - by sisif
    i'm using Haskell with the Yampa FRP library which uses the arrows language extension. how can i do a simple putStrLn in a SF? mySF = proc x -> do y <- identity -< x*x putStrLn "Hello World!" ++ show y returnA -< y the arrow syntax complains about the expression not bein an arrow (of course), but even with arrows i get no output output <- identity -< putStrLn "Hello World!"

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  • I was stuck in implementing Simple Ftp with Winsock [migrated]

    - by user67449
    I want to implement a SimpleFtp with Winsock. But I was stuck in the maybe the file stream reading and writing. This is the Server. #include <WinSock2.h> #include <memory.h> #include <stdio.h> #include <iostream> using namespace std; #pragma comment(lib, "ws2_32.lib") #define MAX_FILE_NAME 100 #define DATA_PACK_SIZE 80*1000 // ??DataPack?????80KB #define SOCKKET_BUFFER_SIZE 80*1000 // socket??? #define FILE_BUFFER_SIZE DATA_PACK_SIZE-MAX_FILE_NAME-4*sizeof(int)-sizeof(u_long) //?????,??,??????content????? #define CONTENT_SIZE FILE_BUFFER_SIZE // DataPack?????content??? // Define a structure to hold the content of a file typedef struct FilePack{ char fName[MAX_FILE_NAME]; // File's name int fLen; // File's length int packNum; // Number of the DataPack int packLen; // DataPack's length int packCount; int contenLen; // the content length the DataPack actually holds u_long index; // ?????????? char content[CONTENT_SIZE]; // DataPack?????? }DataPack, *pDataPack; void WinsockInitial(){ WSADATA wsaData; WORD wVersionRequested; int err; wVersionRequested=MAKEWORD(2,2); err=WSAStartup(wVersionRequested, &wsaData); if(err!=0){ cout<<"Error at WSAStartup()."<<endl; exit(0); } if( LOBYTE(wsaData.wVersion)!=2 || HIBYTE(wsaData.wVersion)!=2 ){ cout<<"Error at version of Winsock. "<<endl; WSACleanup(); exit(0); } } void SockBind(SOCKET sock, int port, sockaddr_in &addrsock){ addrsock.sin_family=AF_INET; addrsock.sin_port=htons(port); addrsock.sin_addr.S_un.S_addr=htonl(INADDR_ANY); if( bind(sock, (sockaddr*)&addrsock, sizeof(addrsock)) == SOCKET_ERROR ){ cout<<"Error at bind(). Error: "<<GetLastError()<<endl; closesocket(sock); WSACleanup(); exit(0); } } void SockListen(SOCKET sock, int bak){ int err=listen(sock, bak); if(err==SOCKET_ERROR){ cout<<"Error at listen()."<<WSAGetLastError()<<endl; closesocket(sock); WSACleanup(); exit(0); } } int SockSend(DataPack &dataPack, SOCKET sock, char *sockBuf){ int bytesLeft=0, bytesSend=0; int idx=0; bytesLeft=sizeof(dataPack); // ?DataPack?????sockBuf??? memcpy(sockBuf, &dataPack, sizeof(dataPack)); while(bytesLeft>0){ bytesSend=send(sock, &sockBuf[idx], bytesLeft, 0); if(bytesSend==SOCKET_ERROR){ cout<<"Error at send()."<<endl; return 1; } bytesLeft-=bytesSend; idx+=bytesSend; } return 0; } int GetFileLen(FILE *fp){ // ?????? if(fp==NULL){ cout<<"Invalid argument. Error at GetFileLen()."<<endl; exit(0); } fseek(fp, 0, SEEK_END); int tempFileLen=ftell(fp); fseek(fp, 0, SEEK_SET); return tempFileLen; } int main(){ int err; sockaddr_in addrServ; int port=8000; // Initialize Winsock WinsockInitial(); // Create a socket SOCKET sockListen=socket(AF_INET, SOCK_STREAM, IPPROTO_TCP); if(sockListen==INVALID_SOCKET){ cout<<"Error at socket()."<<endl; WSACleanup(); return 1; } // Bind the socket. SockBind(sockListen, port, addrServ); // Listen for incoming connection requests cout<<"Waiting for incoming connection requests..."<<endl; SockListen(sockListen, 5); // Accept the connection request. sockaddr_in addrClient; int len=sizeof(addrClient); SOCKET sockConn=accept(sockListen, (sockaddr*)&addrClient, &len); if(sockConn!=INVALID_SOCKET){ cout<<"Connected to client successfully."<<endl; } // Set the buffer size of socket char sockBuf[SOCKKET_BUFFER_SIZE]; int nBuf=SOCKKET_BUFFER_SIZE; int nBufLen=sizeof(nBuf); err=setsockopt(sockConn, SOL_SOCKET, SO_SNDBUF, (char*)&nBuf, nBufLen); if(err!=0){ cout<<"Error at setsockopt(). Failed to set buffer size for socket."<<endl; exit(0); } //??????????? err = getsockopt(sockConn, SOL_SOCKET, SO_SNDBUF, (char*)&nBuf, &nBufLen); if( SOCKKET_BUFFER_SIZE != nBuf){ cout<<"Error at setsockopt(). ?socket????????"<<endl; closesocket(sockListen); closesocket(sockConn); WSACleanup(); exit(0); } //------------------------------------------------------------------------// DataPack dataPackSend; memset(&dataPackSend, 0, sizeof(dataPackSend)); int bytesRead; int bytesLeft; int bytesSend; int packCount; // Counts how many DataPack needed FILE *frp; // Used to read if(strcpy_s(dataPackSend.fName, "music.mp3")!=0){ cout<<"Error at strcpy_s()."<<endl; return 1; } // Open the file in read+binary mode err=fopen_s(&frp, dataPackSend.fName, "rb"); if(err!=0){ cout<<"Error at fopen_s()."<<endl; return 1; } char fileBuf[FILE_BUFFER_SIZE]; // Set the buffer size of File if(setvbuf(frp, fileBuf, _IONBF, FILE_BUFFER_SIZE)!=0){ cout<<"Error at setvbuf().Failed to set buffer size for file."<<endl; closesocket(sockListen); closesocket(sockConn); WSACleanup(); exit(0); } // Get file's length int fileLen=GetFileLen(frp); cout<<"File ???:"<<fileLen<<" bytes."<<endl; // Calculate how many DataPacks needed packCount=ceil( (double)fileLen/CONTENT_SIZE ); cout<<"File Length: "<<fileLen<<" "<<"Content Size: "<<CONTENT_SIZE<<endl; cout<<"???"<<packCount<<" ?DataPack"<<endl; int i=0; for(i=0; i<packCount; i++){ //?????dataPackSend????? memset(&dataPackSend, 0, sizeof(dataPackSend)); // Fill the dataPackSend if(strcpy_s(dataPackSend.fName, "abc.txt")!=0){ cout<<"Error at strcpy_s()."<<endl; return 1; } dataPackSend.packLen=DATA_PACK_SIZE; dataPackSend.fLen=fileLen; dataPackSend.packCount=packCount; if( packCount==1 ){ //??DataPack??? bytesRead=fread(fileBuf, 1, dataPackSend.fLen, frp); dataPackSend.contenLen=dataPackSend.fLen; memcpy(dataPackSend.content, fileBuf, bytesRead); dataPackSend.packNum=0; //???????DataPack // ?????dataPackSend?Client? if( SockSend(dataPackSend, sockConn, sockBuf)==0 ){ cout<<"??? "<<dataPackSend.packNum<<" ?DataPack"<<endl; } }else if( packCount>1 && i<(packCount-1) ){ // ???(???????) bytesRead=fread(fileBuf, 1, CONTENT_SIZE, frp); dataPackSend.contenLen=CONTENT_SIZE; memcpy(dataPackSend.content, fileBuf, bytesRead); dataPackSend.packNum=i; //?dataPackSend??????Client? if( SockSend(dataPackSend, sockConn, sockBuf)==0 ){ cout<<"??? "<<dataPackSend.packNum<<" ?DataPack."<<endl; } }else{ // ????? bytesRead=fread(fileBuf, 1, (dataPackSend.fLen-i*CONTENT_SIZE), frp); dataPackSend.contenLen=dataPackSend.fLen-i*CONTENT_SIZE; memcpy(dataPackSend.content, fileBuf, bytesRead); dataPackSend.packNum=i; //?dataPackSend???Client? if( SockSend(dataPackSend, sockConn, sockBuf)==0 ){ cout<<"??? "<<dataPackSend.packNum<<" ?DataPack."<<endl; } } } fclose(frp); closesocket(sockListen); closesocket(sockConn); WSACleanup(); return 0; } And this is Client. #include <WinSock2.h> #include <memory.h> #include <stdio.h> #include <iostream> using namespace std; #pragma comment(lib, "ws2_32.lib") #define MAX_FILE_NAME 100 #define DATA_PACK_SIZE 80*1000 // ??DataPack?????80KB #define SOCKKET_BUFFER_SIZE 80*1000 // socket??? #define FILE_BUFFER_SIZE DATA_PACK_SIZE-MAX_FILE_NAME-4*sizeof(int)-sizeof(u_long) //?????,??,??????content????? #define CONTENT_SIZE FILE_BUFFER_SIZE // DataPack?????content??? // Define a structure to hold the content of a file typedef struct FilePack{ char fName[MAX_FILE_NAME]; // File's name int fLen; // File's length int packNum; // Number of the DataPack int packLen; // DataPack's length int packCount; //DataPack??? int contenLen; // the content length the DataPack actually holds u_long index; // ?????????? char content[CONTENT_SIZE]; // DataPack?????? }DataPack, *pDataPack; void WinsockInitial(){ WSADATA wsaData; WORD wVersionRequested; int err; wVersionRequested=MAKEWORD(2,2); err=WSAStartup(wVersionRequested, &wsaData); if(err!=0){ cout<<"Error at WSAStartup()."<<endl; exit(0); } if( LOBYTE(wsaData.wVersion)!=2 || HIBYTE(wsaData.wVersion)!=2 ){ cout<<"Error at version of Winsock. "<<endl; WSACleanup(); exit(0); } } int SockRecv(SOCKET sock, char *sockBuf){ int bytesLeft, bytesRecv; int idx=0; bytesLeft=DATA_PACK_SIZE; while(bytesLeft>0){ bytesRecv=recv(sock, &sockBuf[idx], bytesLeft, 0); if(bytesRecv==SOCKET_ERROR){ cout<<"Error at recv()."<<endl; return 1; } bytesLeft-=bytesRecv; idx+=bytesRecv; } return 0; } int main(){ int err; sockaddr_in addrServ; int port=8000; // Initialize Winsock WinsockInitial(); // Create a socket SOCKET sockClient=socket(AF_INET, SOCK_STREAM, IPPROTO_TCP); if(sockClient==INVALID_SOCKET){ cout<<"Error at socket()."<<endl; WSACleanup(); return 1; } // Set the buffer size of socket char sockBuf[SOCKKET_BUFFER_SIZE]; int nBuf=SOCKKET_BUFFER_SIZE; int nBufLen=sizeof(nBuf); err=setsockopt(sockClient, SOL_SOCKET, SO_RCVBUF, (char*)&nBuf, nBufLen); if(err!=0){ cout<<"Error at setsockopt(). Failed to set buffer size for socket."<<endl; exit(0); } //??????????? err = getsockopt(sockClient, SOL_SOCKET, SO_RCVBUF, (char*)&nBuf, &nBufLen); if( SOCKKET_BUFFER_SIZE != nBuf){ cout<<"Error at getsockopt(). ?socket????????"<<endl; closesocket(sockClient); WSACleanup(); exit(0); } // Connect to the Server addrServ.sin_family=AF_INET; addrServ.sin_port=htons(port); addrServ.sin_addr.S_un.S_addr=inet_addr("127.0.0.1"); err=connect(sockClient, (sockaddr*)&addrServ, sizeof(sockaddr)); if(err==SOCKET_ERROR){ cout<<"Error at connect()."<<GetLastError()<<endl; closesocket(sockClient); WSACleanup(); return 1; }else{ cout<<"Connected to the FTP Server successfully."<<endl; } /* int i=0; int bytesRecv, bytesLeft, bytesWrite; int packCount=0, fLen=0; DataPack dataPackRecv; //?????? SockRecv(sockClient, sockBuf); memcpy(&dataPackRecv, sockBuf, sizeof(dataPackRecv)); cout<<"???? "<<dataPackRecv.packNum<<" ?DataPack."<<endl; cout<<"?DataPack??fName????: "<<dataPackRecv.fName<<endl; //??????? packCount=dataPackRecv.packCount; cout<<"?? "<<packCount<<" ?DataPack."<<endl; fLen=dataPackRecv.fLen; // Create a local file to write into FILE *fwp; err=fopen_s(&fwp, dataPackRecv.fName, "wb"); if(err!=0){ cout<<"Error at creat fopen_s(). Failed to create a local file to write into."<<endl; return 1; } // Set the buffer size of File char fileBuf[FILE_BUFFER_SIZE]; if(setvbuf(fwp, fileBuf, _IONBF, FILE_BUFFER_SIZE)!=0){ cout<<"Error at setvbuf().Failed to set buffer size for file."<<endl; memset(fileBuf, 0, sizeof(fileBuf)); closesocket(sockClient); WSACleanup(); exit(0); } //???????content???? memcpy(fileBuf, dataPackRecv.content, sizeof(dataPackRecv.content)); bytesWrite=fwrite(fileBuf, 1, sizeof(fileBuf), fwp); if(bytesWrite<sizeof(fileBuf)){ cout<<"Error at fwrite(). Failed to write the content of dataPackRecv to local file."<<endl; } //?????packCount-1????????????????? for(int i=1; i<packCount; i++){ // ????????? memset(sockBuf, 0, sizeof(sockBuf)); memset(&dataPackRecv, 0, sizeof(dataPackRecv)); memset(fileBuf, 0, sizeof(fileBuf)); SockRecv(sockClient, sockBuf); memcpy(&dataPackRecv, sockBuf, sizeof(dataPackRecv)); cout<<"???? "<<dataPackRecv.packNum<<" ?DataPack."<<endl; //???? memcpy(fileBuf, dataPackRecv.content, dataPackRecv.contenLen); bytesWrite=fwrite(fileBuf, 1, dataPackRecv.contenLen, fwp); if(bytesWrite<dataPackRecv.contenLen){ cout<<"Error at fwrite(). Failed to write the content of dataPackRecv to local file."<<endl; } } if( (i+1)==packCount ){ cout<<"??DataPack????????!"<<endl; } fclose(fwp); closesocket(sockClient); WSACleanup(); return 0;*/ }

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  • Type signature "Maybe a" doesn't like "Just [Event]"

    - by sisif
    I'm still learning Haskell and need help with the type inference please! Using packages SDL and Yampa I get the following type signature from FRP.Yampa.reactimate: (Bool -> IO (DTime, Maybe a)) and I want to use it for: myInput :: Bool -> IO (DTime, Maybe [SDL.Event]) myInput isBlocking = do event <- SDL.pollEvent return (1, Just [event]) ... reactimate myInit myInput myOutput mySF but it says Couldn't match expected type `()' against inferred type `[SDL.Event]' Expected type: IO (DTime, Maybe ()) Inferred type: IO (DTime, Maybe [SDL.Event]) In the second argument of `reactimate', namely `input' In the expression: reactimate initialize input output process I thought Maybe a allows me to use anything, even a SDL.Event list? Why is it expecting Maybe () when the type signature is actually Maybe a? Why does it want an empty tuple, or a function taking no arguments, or what is () supposed to be?

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  • (newbie) type signature "Maybe a" doesn't like "Just [Event]"

    - by sisif
    i'm still learning Haskell and need help with the type inference please! using packages SDL and Yampa i get the following type signature from FRP.Yampa.reactimate: (Bool -> IO (DTime, Maybe a)) and i want to use it for: myInput :: Bool -> IO (DTime, Maybe [SDL.Event]) myInput isBlocking = do event <- SDL.pollEvent return (1, Just [event]) ... reactimate myInit myInput myOutput mySF but it says Couldn't match expected type `()' against inferred type `[SDL.Event]' Expected type: IO (DTime, Maybe ()) Inferred type: IO (DTime, Maybe [SDL.Event]) In the second argument of `reactimate', namely `input' In the expression: reactimate initialize input output process i thought "Maybe a" allows me to use anything, even a SDL.Event list? why is it expecting "Maybe ()" when the type signature is actually "Maybe a"? why does it want an empty tuple, or a function taking no arguments, or what is () supposed to be?

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  • Writing a report

    - by wvd
    Hello all, Since some time I've been investigating more time into profiling things better, really think about how to do a thing and why. Now I'm going to start a new project, where I will be writing a report about. The report will be about anything what I wrote in the project, why, and I'll be investigating some things and do particular research about them. I've seen some reports, such as game programming in Haskell using FRP. However, after reading several reports they all seem to be build different. I have a few questions about writing a report: 1] What are the things I really should include, and what are the things I really shouldn't include? 2] Is it useful to include graphs about different methods/approaches to a several problem, where you only included one into your project, to show WHY you didn't include the other methods. Or should I just explain the method/approach used into the project. 3] Should I only be writing the report after I've completed the project, or should I also write pages about what I expect, how I'm going to build the software? Thanks, William van Doorn

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  • Using NHibernate to map a nChar column to an enumerated type

    - by Morrislgn
    Hello Folks, I am trying to map a table frp, a SQL Server 2005 DB to a class which contains an enum: public class MyClass{ private YesNoOptional addressSetting; public YesNoOptional AddressSetting{ {get; set;} } } public enum YesNoOptional { Yes, No, Optional } This will dictate that one of three values is inserted into the corresponding column - 'Y', 'N', 'O'. This column is of type nchar(1). My mapping file is like so (addressSetting is the property which is causing the problem): <class name="IncidentDefinition" table="IR_INCIDENT_DEF" lazy="false" > <id name="Guid" column="INT_GUID" > <generator class="guid"></generator> </id> <property name="Reference" column="INT_REF" ></property> <property name="Description" column="INT_DESCRIPTION" ></property> <property name="AddressSetting" column="INT_ADDRESS_REQ" ></property> <property name="Active" column="INT_ACTIVE" type="YesNo"></property> <property name="PinDocId" column="INT_PIN_DOC_ID"></property> </class> Using the config above I get the following error: NHibernate.ADOException: could not initialize a collection: System.FormatException: Input string was not in a correct format.. If I try to map the enum using a custom type like so: <property name="AddressSetting" column="INT_ADDRESS_REQ" type="ML.Types.YesNoOptional, ML.Types" ></property> Error: System.FormatException: Input string was not in a correct format. Next, if I try using a specific type like so: <property name="AddressSetting" column="INT_ADDRESS_REQ" type="String" ></property> This error is generated: NHibernate.PropertyAccessException: The type System.String can not be assigned to a property of type System.ArgumentException: Object of type 'System.String' cannot be converted to type 'ML.Types.YesNoOptional'.. As a last resort I tried to specify the type as a char like so: <property name="AddressSetting" column="INT_ADDRESS_REQ" type="Char" ></property> This works a bit better, as it in it doesnt throw an error, however instead of returning the character from the table and mapping it to the enumerated type the ASCII value of the character is returned instead - so Y is represented by 89! I am hoping someone can explain what I am doing wrong and\or how why this is happening please? Thanks Morris

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