Re: Passing function(whose parameter would be dynamic and the type is unknown) as a parameter to another function.

[vino.B via Digitalmars-d-learn]

On Monday, 9 July 2018 at 15:49:50 UTC, Alex wrote:
On Monday, 9 July 2018 at 15:40:53 UTC, vino.B wrote:
On Sunday, 8 July 2018 at 19:10:24 UTC, Alex wrote:
On Sunday, 8 July 2018 at 18:46:31 UTC, vino.B wrote:
 Request you help, in the below code we pass the function 
"Testfun" as a parameter to another function "process" in 
order for the function "process" to work we have to specify 
the type of the parameter that is passed to the function "(T 
function(string, int) coRoutine, string Test, int Size) ", 
so now how do we pass a function whose parameter would be 
dynamic and the type is unknown.

What do you mean with a "function with dynamic parameters" 
and "unknown type"?

But how about

´´´
void main()
{
        process!fun();
}

void process(alias coRoutine, T...)(T params)
{
        coRoutine(params);
}

auto fun(T...)(T params)
{

}
´´´

HI Alex,

 I tried you method, but it not working as expected, the 
process!fun1(Test1) works but the process!fun2(Test1, Size ) 
does not work, instead of displaying the value (Test, 1) it 
output's the parameter "Test1".

Output:
Test
Test1

If I comment process!fun1(Test1); then the output is same

Output :
Test1

import std.stdio: writeln;


void main()
{
    string Test1 = "Test";
    int Size = 1;
    process!fun1(Test1);
    process!fun2(Test1, Size );
}

void process(alias coRoutine, T...)(T params)
{
        coRoutine(params);
}

auto fun1(T...)(T params)
{
   writeln(params);
}

auto fun2(T...)(T params)
{
   writeln(params);
}

From,
Vino.B

As I can see, this is the expected output.
The "1" after "Test" is the value of parameter "Size"...

Hi Alex,

 Thank you a lot, i was able to improvise using your logic, and i 
need more help, the below code is working as expected using your 
logic, now how do i get the return type of the function

Request Help:
void process(alias coRoutine, T...)(Array!string Dirlst, T params)
{
      ReturnType!coRoutine rData;   ///// This line is not working
      alias scRType = typeof(coRoutine(string.init, T.init));
      auto PFresult = taskPool.workerLocalStorage!scRType();
      foreach (string FFs; parallel(Dirlst[],1)) { PFresult.get 
~= coRoutine(FFs, params); }
      foreach(i; PFresult.toRange) { rData ~= i[][]; }
}

Error:
test.d(206): Error: template instance 
`std.traits.ReturnType!(coAgedDirClean)` does not match template 
declaration ReturnType(func...) if (func.length == 1 && 
isCallable!func)


Working Code:
auto coAgedDirClean(T...)(string FFs, T params)  {
     auto dFiles = Array!(Tuple!(string, 
SysTime))(dirEntries(FFs, SpanMode.shallow).filter!(a => a.isFile 
&& a.size > params[0]).map!(a => tuple(a.name, 
a.timeLastModified)));
     return dFiles;
}

auto coAgedDirDelete(T...)(string FFs, T params)  {
     auto dFiles = Array!(Tuple!(string, 
SysTime))(dirEntries(FFs, SpanMode.shallow).filter!(a => a.isFile 
&& a.size > params[0]).map!(a => tuple(a.name, 
a.timeLastModified)));
     if (params[1] == "run" && !dFiles.empty) {  foreach(d; 
parallel(dFiles[], 1)) { remove(d[0]); }}
     return dFiles;
}

void process(alias coRoutine, T...)(Array!string Dirlst, T params)
{
      alias scRType = typeof(coRoutine(string.init, T.init));
      auto PFresult = taskPool.workerLocalStorage!scRType();
      foreach (string FFs; parallel(Dirlst[],1)) { PFresult.get 
~= coRoutine(FFs, params); }
      foreach(i; PFresult.toRange) { writeln(i[][]); }
}

void main()
{
    Array!string AgedDir, DeleteDir;
    AgedDir.insert("C:\\Temp\\TEAM1");
    DeleteDir.insert("C:\\Temp\\BACKUP1");
    ulong Size = 102;
    string Step = "run";
    process!coAgedDirClean(AgedDir, Size );
    process!coAgedDirDelete(DeleteDir, Size, Step);
}

From,
Vino.B