On Wednesday, 16 July 2014 at 23:24:24 UTC, Joseph Rushton Wakeling via Digitalmars-d-learn wrote:
> Are you interested in having each character in the sequence randomly chosen independently of all the others, or do you want a random subset of all available characters (i.e. no character appears more than once), or something else again?

Just a random dchar (ciode point) sample like this:

/** Generate Random Contents of $(D x).
    See also: http://forum.dlang.org/thread/emlgflxpgecxsqweauhc@forum.dlang.org
 */
auto ref randInPlace(ref dchar x) @trusted
{
    auto ui = uniform(0,
                      0xD800 +
                      (0x110000 - 0xE000) - 2 // minus two for U+FFFE and U+FFFF
        );
    if (ui < 0xD800)
    {
        return x = ui;
    }
    else
    {
        ui -= 0xD800;
        ui += 0xE000;

        // skip undefined
        if (ui < 0xFFFE)
            return x = ui;
        else
            ui += 2;

        assert(ui < 0x110000);
        return x = ui;
    }
}

I don't know how well this plays with

unittest
{
    import dbg;
    dln(randomized!dchar);
    dstring d = "alphaalphaalphaalphaalphaalphaalphaalphaalphaalpha";
    dln(d.randomize);
}

though.

See complete logic at

https://github.com/nordlow/justd/blob/master/random_ex.d