Translating Modula2 into D: variant records, pointer

[Jarrett Billingsley]

"BLS" <Killing_Zoe at web.de> wrote in message 
news:eo04h3$1us4$1 at digitaldaemon.com...
> Translating Modula2 into D: Subject: variant records,pointer
>
> Hi I have some Modula2 code which I would like to translate in D.
> I often have to use something like that :
> ...
> So: How do I have to implement this snippet in D ?
> Many thanks !!!! in advance; Bjoern

Something like:

module snippet;

struct Node
{
    Node* suc;
    Node* alt;
    bool terminal;

    union
    {
        char tsym;
        Header* nSym;
    }
}

struct Header
{
    char sym;
    Node* entry;
    Header* suc;
}

Header* list;
Header* sentinel;

void Find(char s, inout Header* h)
{
    Header* h1 = list;
    sentinel.sym = s;

    sentinel = new Header;

    h = h1;
    // etc.
}

One thing I'm not real sure on is the variant record.  The closest thing I 
think in D is a union, but nothing prevents you from accessing either tsym 
or nSym in Node at any time.  I guess in Modula2, if 'terminal' is true, you 
can only access tsym, and otherwise you can only access nSym?