copying directories recursively

[anonymous via Digitalmars-d-learn]

TL;DR: Is there a simple way to copy directories recursively?

My goal is to copy the directories ./src/dlang.org/{css,images,js} and 
their contents to ./ddo/{css,images,js}.

Naively I tried this:

----
void main()
{
     import file = std.file;
     auto outputPath = "./ddo/";
     foreach (dir; ["css", "images", "js"])
     {
         file.copy("./src/dlang.org/" ~ dir, outputPath ~ dir);
     }
}
----

But that fails with "std.file.FileException at std/file.d(3154): 
src/dlang.org/css: Is a directory".

`copy` doesn't have a parameter to enable copying directories, and I 
can't find any `copyDir` or `copyRecurse` or some such.

As it looks I'll end up implementing my own `copyRecurse`:

----
void copyRecurse(string from, string to)
{
     import std.file: copy, dirEntries, isDir, isFile, mkdirRecurse, 
SpanMode;
     import std.path: buildNormalizedPath, buildPath;

     from = buildNormalizedPath(from);
     to = buildNormalizedPath(to);

     if (isDir(from))
     {
         mkdirRecurse(to);

         auto entries = dirEntries(from, SpanMode.breadth);
         foreach (entry; entries)
         {
             auto dst = buildPath(to, entry.name[from.length + 1 .. $]);
                 // + 1 for the directory separator
             if (isFile(entry.name)) copy(entry.name, dst);
             else mkdirRecurse(dst);
         }
     }
     else copy(from, to);
}
----

Is there a simpler way to do this?