Passing Function as an argument to another Function

[Ali Çehreli]

On 12/04/2017 04:52 AM, Vino wrote:

 > if the Variable  CleanDirlst is defined as "auto"

Every expression has a type. 'auto' in that context (or 'const', etc.) 
just helps with not spelling-out that type. You can see the type with 
pragma(msg) and typeof:

     auto someExpression = [ "one" : 1, "two" : 2 ];
     pragma(msg, typeof(someExpression));    // Prints int[string]

 >  can we define "auto" as below(auto Dirlst).

 > void ptProcessFiles() (auto Dirlst,  Array!(Tuple!(string, string))
 > function(string, string, int) coRoutine, File logF, File logE, string
 > Step, int Aged)

You can use templates. Here is my introduction to the concept:

   http://ddili.org/ders/d.en/templates.html

However, in this case a simple 'alias' will do:

alias MyListType = int[string];

void foo(MyListType arg) {
     // ...
}

 > Q2 :
 > How do we define an "auto" function(auto function(string, string, int)
 > coRoutine)
 > void ptProcessFiles() (auto Dirlst,  auto function(string, string, int)
 > coRoutine, File logF, File logE, string Step, int Aged)

alias helps in that case as well:

alias MyCoRoutineType = MyListType function(string, string, int);

void ptProcessFiles(MyListType Dirlst, MyCoRoutineType coRoutine, File 
logF, File logE, string Step, int Aged) {
     // ...
}

Likewise, ptProcessFiles can be a template as well, where the type of 
coRoutine can be a template argument but not needed in this case.

Ali