How to get a sort template in MML 5.5.7, and how do you use it?

fxsaber 2025.02.06 08:09 #2891

for (long Chart = ChartFirst(); Chart != -1; Chart = ChartNext(Chart))

Such a loop will loop through all charts, including even nested OBJ_CHART variants (for which OBJPROP_CHART_ID was called)

fxsaber 2025.02.06 13:36 #2892

The function to get a list of all charts and the function to close a chart.

// List of all charts, including CHART_IS_OBJECT.
int GetCharts( long &Charts[], long Chart = 0 )
{
  if (Chart)
    for (uint i = ObjectsTotal(Chart, -1, OBJ_CHART); (bool)i--;)
    {  
      const long NewChart = ObjectGetInteger(Chart, ObjectName(Chart, i, -1, OBJ_CHART), OBJPROP_CHART_ID);
      
      if (NewChart)
      {
        Charts[ArrayResize(Charts, ArraySize(Charts) + 1) - 1] = NewChart;
        
        GetCharts(Charts, NewChart);      
      }
    }
  else
  {
    ArrayFree(Charts);
    
    for (long Chart = ChartFirst(); Chart != -1; Chart = ChartNext(Chart))
    {
      long Tmp;
      
      if (!ChartGetInteger(Chart, CHART_IS_OBJECT, -1, Tmp))
        ResetLastError();
      else if (!Tmp) 
      {
        Charts[ArrayResize(Charts, ArraySize(Charts) + 1) - 1] = Chart;
        
        GetCharts(Charts, Chart);
      }
    }
  }
  
  return(ArraySize(Charts));
}

// Closes and CHART_IS_OBJECT charts.
bool ChartCloseFull( long chart_id = 0, long Chart = 0 )
{
  bool Res = false;
  long Tmp;
  
  if (Chart)  
    for (uint i = ObjectsTotal(Chart, -1, OBJ_CHART); !Res && (bool)i--;)
    {
      const string Name = ObjectName(Chart, i, -1, OBJ_CHART);      
      const long NewChart = ObjectGetInteger(Chart, Name, OBJPROP_CHART_ID);
      
      ResetLastError();
      Res = ((NewChart == chart_id) && (ObjectDelete(Chart, Name) ||
                                        (_LastError == ERR_OBJECT_ERROR) ||
                                        (_LastError == ERR_OBJECT_NOT_FOUND))) ||
            ChartCloseFull(chart_id, NewChart);
    }
  else if (!ChartGetInteger(chart_id, CHART_IS_OBJECT, -1, Tmp) || Tmp)
  {
    ResetLastError();
    
    if (!chart_id)
      chart_id = ChartID();
    
    for (long Chart = ChartFirst(); !Res && (Chart != -1); Chart = ChartNext(Chart))
      if (!ChartGetInteger(Chart, CHART_IS_OBJECT, -1, Tmp))
        ResetLastError();
      else if (!Tmp)
        Res = ChartCloseFull(chart_id, Chart);
  }
  else
    Res = ChartClose(chart_id);
  
  return(Res);
}

Example.

long CreateChart( const long Chart = 0 )
{
  const string Name = (string)MathRand();
  
  return(ObjectCreate(Chart, Name, OBJ_CHART, 0, 0, 0) ?  ObjectGetInteger(Chart, Name, OBJPROP_CHART_ID) : -1);
}

void OnStart()
{  
  long NewCharts[];
  const int Size = ArrayResize(NewCharts, 9);
  
  for (int i = 0; i < Size; i++)
  {
    NewCharts[i] = CreateChart((bool)(i %3) ? NewCharts[i - 1] : 0);
    
    Sleep(100);
  }
  
  Print("\nCreated charts:");
  ArrayPrint(NewCharts);

  long Charts[];
  
  Print("\nList of all charts:");
  GetCharts(Charts);
  ArrayPrint(Charts);

  for (int i = Size; (bool)i--;)
  {
    Print("\nDelete " + (string)NewCharts[i] + " - " + (string)ChartCloseFull(NewCharts[i]));
    
    Sleep(100);
    
    Print("List of all charts:");
    GetCharts(Charts);
    ArrayPrint(Charts);
  }  
}

Result.

Created charts:
[0] 132503570123939383 132503570123939384 132503570123939385 132503570123939386 132503570123939387
[5] 132503570123939388 132503570123939389 132503570123939390 132503570123939391

List of all charts:
[0] 132503570123939382 132503570123939386 132503570123939387 132503570123939388 132503570123939389
[5] 132503570123939390 132503570123939391 132503570123939383 132503570123939384 132503570123939385

Delete 132503570123939391 - true
List of all charts:
[0] 132503570123939382 132503570123939386 132503570123939387 132503570123939388 132503570123939389
[5] 132503570123939390 132503570123939383 132503570123939384 132503570123939385

Delete 132503570123939390 - true
List of all charts:
[0] 132503570123939382 132503570123939386 132503570123939387 132503570123939388
[4] 132503570123939389 132503570123939383 132503570123939384 132503570123939385

Delete 132503570123939389 - true
List of all charts:
132503570123939382 132503570123939386 132503570123939387 132503570123939388 132503570123939383 132503570123939384 132503570123939385

Delete 132503570123939388 - true
List of all charts:
132503570123939382 132503570123939386 132503570123939387 132503570123939383 132503570123939384 132503570123939385

Delete 132503570123939387 - true
List of all charts:
132503570123939382 132503570123939386 132503570123939383 132503570123939384 132503570123939385

Delete 132503570123939386 - true
List of all charts:
132503570123939382 132503570123939383 132503570123939384 132503570123939385

Delete 132503570123939385 - true
List of all charts:
132503570123939382 132503570123939383 132503570123939384

Delete 132503570123939384 - true
List of all charts:
132503570123939382 132503570123939383

Delete 132503570123939383 - true
List of all charts:
132503570123939382

fxsaber 2025.02.08 13:18 #2893

I use such a universal construction of setting on/off Common-folder via file name.

int FileOpen2( string file_name, int open_flags,
               const short delimiter = '\t', const uint codepage = CP_ACP )
{
  open_flags |= ::StringReplace(file_name, "*", NULL) ? FILE_COMMON : 0;
  
  return(::FileOpen(file_name, open_flags, delimiter, codepage));
}

If the file name contains an asterisk, it will open in the Common folder, otherwise - as specified.

Maxim Kuznetsov 2025.02.08 13:34 #2894

Who knows how to make this work ?

// тестовый класс
class Foo {
public:
   Foo() { payload=MathRand(); }
   ~Foo() {}
public:
   int payload;   
};

int CompareByPayload(Foo *one,Foo *two)
{
   return two.payload - one.payload; 
}

/* // КСТАТИ, если раскоментить, будет "fatal error" компилятора
template <typename T>
int CompareByPayload(T *one,T *two)
{
   return two.payload - one.payload; 
}
*/

// ШАБЛОННАЯ СОРТИРОВКА
// для массива с указателями на объекты
template <typename T>
typedef int (*CompareFunction)(T *,T *);

template <typename T>
int Sort(T *&_arr[],CompareFunction _cmp)
{
   // тут какая-то сортировка
   return 0;
}

Foo *arr[];
void OnStart()
{
   ArrayResize(arr,100);

   for(int i=0;i<100;i++)
      arr[i]=new Foo();

   Sort(arr,CompareByPayload);

   for(int i=0;i<100;i++) {
      Print("payload=%d",arr[i].payload);
      delete arr[i];
   }
}

to get a Sort template ( array_pointers, compare_function )

fxsaber 2025.02.08 16:39 #2895

Maxim Kuznetsov #:

Who knows how to make something like this work ?

to get a Sort template ( array_pointers, compare_function )

Template pointers to functions do not work in MQL5.

Maxim Kuznetsov 2025.02.08 21:26 #2896

fxsaber #:

Template pointers to functions do not work in MQL5.

sadly... :-(

so until there is a pointer to a member-function (what a word that is), it is premature to talk about human OO in MQL.

fxsaber 2025.02.08 21:36 #2897

Maxim Kuznetsov #:

It is premature to talk about human OO in MQL

Forum on trading, automated trading systems and testing trading strategies

Do I need multiple inheritance of interfaces in MQL?

Koldun Zloy, 2025.01.23 14:29

It is a feature that can easily be done without.

It will not untie anyone's hands.

It has nothing to do with development.

Any questions from newcomers Looking for patterns How do you backtest

Maxim Kuznetsov 2025.02.08 21:58 #2898

fxsaber #:

Is there a modern language where you can't make a template Sort() ?

PS/ unlike multiple inheritance it can be done ugly through #define SORT(arr,func). But that's cheesy from the 80's. Why it's not in templates is a mystery to me

[Archive!] FOREX - Trends, Compile Error when use Asynchronous and multi-threaded programming

amrali 2025.02.08 22:39 #2899

fxsaber #:

Template pointers to functions do not work in MQL5.

There is a nice solution to overcome that limitation of MQL. The trick is to pass the templated CompareFunc to the generic sort function both as a function pointer + a type parameter T .

This trick helps the compiler to resolve the typename parameters..

GenericSortTemplated.mq5

// templated class
template <typename T>
class Foo {
public:
   Foo() { payload=(T)10*MathRand()/MathRand(); }
   ~Foo() {}
public:
   T payload;
};

// templated compare function for different types of payloads
template <typename T>
bool CompareByPayload(T one, T two)
{

   return one.payload < two.payload;
}

//--------------------------------------------------------------------------------------------
// TEMPLATE SORTING
// function is templated for any type of array (e.g., int[], double[], pointers to objects[]).
// The CompareFunc type is a pointer to comparison function that can accept different types.
//--------------------------------------------------------------------------------------------
template <typename T, typename CompareFunc>
void GenericSort(T &a[], CompareFunc compare)
{
   for(int i=1; i < ArraySize(a); ++i)
      for(int j=i; j>0 && compare( a[j], a[j-1] ); j--)
      {
         T tmp=a[j]; a[j]=a[j-1]; a[j-1]=tmp;
      }
}

// custom sort function for different types of payloads
template< typename T >
void Sort(T& a[])
{
   typedef bool (*CompareFunc)( T, T );

   GenericSort< T, CompareFunc >( a, CompareByPayload< T > );
}

Foo<int>   *arr[];
Foo<float> *flt[];

void OnStart()
{
   int n = 7;
   ArrayResize(arr,n);
   ArrayResize(flt,n);

   for(int i=0;i<n;i++) {
      arr[i]=new Foo<int>();
      flt[i]=new Foo<float>();
   }

   Sort(arr);
   Sort(flt);

   for(int i=0;i<n;i++) {
      printf("%d. payload=%s",i,(string)arr[i].payload);
      delete arr[i];
   }

   for(int i=0;i<n;i++) {
      printf("%d. payload=%s",i,(string)flt[i].payload);
      delete flt[i];
   }
}

The sort function is templated. The compare function is also templated. The highlight colors indicate how the typename parameters are specialized and resolved.

output:

GenericSort (EURUSD,H1) 0. payload=1
GenericSort (EURUSD,H1) 1. payload=5
GenericSort (EURUSD,H1) 2. payload=6
GenericSort (EURUSD,H1) 3. payload=7
GenericSort (EURUSD,H1) 4. payload=10
GenericSort (EURUSD,H1) 5. payload=30
GenericSort (EURUSD,H1) 6. payload=230

GenericSort (EURUSD,H1) 0. payload=1.2722387313842773
GenericSort (EURUSD,H1) 1. payload=2.1265437602996826
GenericSort (EURUSD,H1) 2. payload=2.4967143535614014
GenericSort (EURUSD,H1) 3. payload=4.115740776062012
GenericSort (EURUSD,H1) 4. payload=7.864346981048584
GenericSort (EURUSD,H1) 5. payload=11.456646919250488
GenericSort (EURUSD,H1) 6. payload=18.580562591552734

Services. Are they up Errors, bugs, questions Any questions from newcomers

Paolo Besana 2025.02.11 09:23 #2900

Hello everyone.

I created a WPF application using .net. While I was reading the documentation about imports at https://www.mql5.com/en/book/advanced/libraries/libraries_import and it clearly states:

Functions are imported from compiled MQL5 modules (*.ex5 files) and from Windows dynamic library modules (*.dll files).

While I was conducting some tests I tried to build my application as .exe instead of .dll and imported it into my mql5 EA and saw that the compiler doesn't give me any errors and also I can use static functions inside the program.

Since I couldn't find anything about importing .exe programs in the documentation I was wondering if that implies something I am now aware of. Does it impact the lifecycle of the EA? Does the terminal manage .exe imports differently from .dlls in any way?

Thanks for your time.

graceful shutdown of services compiling - metaeditor.exe help Help in DLL import

Features of the mql5 language, subtleties and tricks - page 290

Example.

Result.