Proposal of a general do-while loop

[Benjamin Phillips]

downs Wrote:

> Taro Kawagishi wrote:
> > I think a more natural way to express the logic is to write the code as in listing 4.
> > 
> >     // listing 4
> >     size_t pos = 0;
> >     do {
> >         pos = text.find(pattern, pos);
> >     } while (pos != string::npos) {
> >         cout << "pattern found at " << pos << "\n";
> >         ++pos;
> >     }
> > 
> > The meaning of
> > 
> >     do {
> >         aa;
> >     } while (bb) {
> >         cc;
> >     }
> > 
> > is
> > 
> >     while (true) {
> >         aa;
> >         if (not bb) {
> >             break;
> >         }
> >         cc;
> >     }
> 
> void doWhile(void delegate() pre, lazy bool cond, void delegate() post) {
>    while (true) {
>      pre;
>      if (!cond()) break;
>      post;
>    }
> }
> 
> // listing 4, modified
> size_t pos=0;
> doWhile ({
>    pos=text.find(pattern, pos);
> }, pos!=string::npos, {
>    writefln("Pattern found at ", pos);
>    ++pos;
> });
> 
> Not tested, but should work.
> Have fun!

Being able to create templates that basically act like new keywords is one thing I love about D. I think your solution is better than any of the others posted.