I have a map of sha1 values to file names, thus:

    char[][][char[]] sha_map;

I would like to loop over the values of the map, and print the file names that are duplicates, sort of like this:

    foreach (key; sha_map.keys) {
        auto file_names = sha_map[key];

        // if only one file name, it is unique, so skip it
        if (file_names.length <= 1) continue;

        // sort file names by criteria that place the file
        // to retain at the front of the array.

        sort(file_names, retain_criteria_comparator());

        foreach (i, file_name; file_names) {
            if (i == 0) continue;
            writefln(file_name);
        }
    }

But I'm at a loss how to do the sort I would like.  Any advice would be appreciated.



Bill
--
r * e * @ * o * y * a * c * m
* a * l * z * p * r * . * o *

Bill Lear wrote:
> I have a map of sha1 values to file names, thus:
> 
>     char[][][char[]] sha_map;
> 
> I would like to loop over the values of the map, and print
> the file names that are duplicates, sort of like this:
> 
>     foreach (key; sha_map.keys) {
>         auto file_names = sha_map[key];
> 
>         // if only one file name, it is unique, so skip it
>         if (file_names.length <= 1) continue;
> 
>         // sort file names by criteria that place the file
>         // to retain at the front of the array.
> 
>         sort(file_names, retain_criteria_comparator());
> 
>         foreach (i, file_name; file_names) {
>             if (i == 0) continue;
>             writefln(file_name);
>         }
>     }
> 
> But I'm at a loss how to do the sort I would like.  Any advice would
> be appreciated.
> 
> 
> 
> Bill
> --
> r * e * @ * o * y * a * c * m
> * a * l * z * p * r * . * o *

What I would do is this:

struct sort_fname {
    char[] fname;

    int opCmp(sort_fname other)
    {
       // or whatever
       return other.fname.length > fname;
    }
}

Now, use the type sort_fname in place of char[]:

  char[][][char[]] sha_map;

   becomes

  sorted_fname[][char[]] sha_map;

You can pick whatever criteria you like.  Because this is a struct, you can use "sorted_fname" in the opCmp().  If it was a class, you'd need to use "int opCmp(Object other)", and cast 'other' to the right type to verify that its the right kind of class.  In this case struct is easier.

The sort just looks like:
   file_names.sort;

Kevin