Two changes to from...import: 1) "from M import X" now works even if M is not a real module; it's basically a getattr() operation with AttributeError exceptions changed into ImportError. 2) "from M import *" now looks for M.__all__ to decide which names to import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but filters out names starting with '_' as before. Whether or not __all__ exists, there's no restriction on the type of M.

/* hypot() replacement */

#include "config.h"
#include "pyport.h"

double hypot(double x, double y)
{
	double yx;

	x = fabs(x);
	y = fabs(y);
	if (x < y) {
		double temp = x;
		x = y;
		y = temp;
	}
	if (x == 0.)
		return 0.;
	else {
		yx = y/x;
		return x*sqrt(1.+yx*yx);
	}
}