On Sat, Mar 27, 2010 at 03:34, strtr <strtr@spam.com> wrote:

Ellery Newcomer Wrote:

> I just noticed that dup does not dup deep.
>
> In a two second search I couldn't find any reason for or against, but
> I'd kinda like it if
>
> auto r2 = r.dup;
> r2[i][j] = 0;
> r[i][j] = 1;
> assert(r2[i][j] != r[i][j]);
>
> held.

There have been discussions about this before.
Here is the first I found (couldn't find my own .ddup request :)
http://www.digitalmars.com/webnews/newsgroups.php?art_group=digitalmars.D&article_id=12631

I sent a proposal for deep dup a few hours after your discussion, bu no one commented on it. And now I can't find it... hmm. Maybe the mail didn't make it.

Anyway, here it is:

template TypeofDeepdup(T)
{
    alias typeof(deepdup(T.init)) TypeofDeepdup;
}

ref Unqual!T deepdup(T)(T t) if (is(T == struct) && !is(T.Types))
{
    staticMap!(TypeofDeepdup, typeof(t.tupleof)) tup;
    foreach(i,Type; tup) { tup[i] = deepdup(t.tupleof[i]);}
    return Unqual!T(tup);
}

Tuple!(staticMap!(TypeofDeepdup, T.Types))
deepdup(T)(T t) if (is(T.Types)) // Tuples
{
    staticMap!(TypeofDeepdup, T.Types) tup;
    foreach(i,Type; tup) { tup[i] = deepdup(t.field[i]);}
    return tuple(tup);
}

Unqual!T deepdup(T)(T t) if (is(T == class))
{
    staticMap!(TypeofDeepdup, typeof(t.tupleof)) tup;
    foreach(i,Type; tup) { tup[i] = deepdup(t.tupleof[i]);}
    return new Unqual!T(tup);
}

TypeofDeepdup!(ElementType!T)[] deepdup(T)(T t) if (isDynamicArray!T)
{
    auto result = new TypeofDeepdup!(ElementType!T)[](t.length);
    foreach(i, elem; t) result[i] = deepdup(elem);
    return result;
}

TypeofDeepdup!(ElementType!T)[T.length] deepdup(T)(T t) if (isStaticArray!T)
{
    TypeofDeepdup!(ElementType!T)[T.length] result = t;
    foreach(ref elem; result) elem = deepdup(elem);
    return result;
}

TypeofDeepdup!T* deepdup(T)(T* t)
{
    return &deepdup(*t);
}

Unqual!T deepdup(T)(T t) if (!is(T == struct) && !is(T == class) && !isArray!T && !is(T.Types) && !isPointer!T)
{
    return cast(Unqual!T)t;
}

It seems to work well enough for my purposes, but still has some limitations: for example, it unqualifies everything (no more const / immutable after dupping).

Philippe