goto

[Brad Roberts]

Andrei Alexandrescu wrote:
> I was coding a simple Euclidean distance function with limit:
> 
> double euclideanDistance(Range)(Range a, Range b, double limit)
> {
>     limit *= limit;
>     double result = 0;
>     for (; !a.empty; a.next, b.next)
>     {
>         enforce(!b.empty);
>         auto t = a.head - b.head;
>         result += t * t;
>         if (result >= limit) goto thatsit;
>     }
>     enforce(b.empty);
>   thatsit:
>     return sqrt(result);
> }
> 
> How would an elegant goto-less approach look like? It should not
> duplicate code, e.g. the call to sqrt.
> 
> 
> Andrei

How about:

> double euclideanDistance(Range)(Range a, Range b, double limit)
{
    limit *= limit;
    double result = 0;
    for (; !a.empty; a.next, b.next)
    {
        enforce(!b.empty);
        auto t = a.head - b.head;
        result += t * t;
        if (result >= limit)
        {
            b.clear;
            break;
        }
    }
    enforce(b.empty);
    return sqrt(result);
}