C++ Ranges proposal for the Standard Library

[Marco Leise via Digitalmars-d]

Am Fri, 17 Oct 2014 09:17:51 +0000
schrieb "ZombineDev" <valid_email at he.re>:

> I saw [this][0] proposal for adding ranges to C++'s standard
> library. The [paper][1] looks at D style ranges, but concludes:
> 
> > Since iterators can implement D ranges, but D ranges cannot be 
> > used to implement iterators, we conclude that iterators form a 
> > more powerful and foundational basis.
> 
> What do you guys think?
> 
> [0]: https://isocpp.org/blog/2014/10/ranges
> [1]: https://ericniebler.github.io/std/wg21/D4128.html

True. Iterators are more foundational, ranges are more
neat-o. ;)
When you look at this C++ function as part of a signal
processing home work you know why you don't want to see them
in top level code:

// C++

double mittelwert(const vector<double>& vektor)
{
	vector<double>::const_iterator it;
	double summe = 0;
	for (it = vektor.begin(); it != vektor.end(); ++it)
	{
		summe += *it;
	}
	return summe / vektor.size();
}

// D (removing iterators)

double mittelwert(in double[] vektor)
{
	double summe = 0;
	foreach (wert; vektor)
	{
		summe += wert;
	}
	return summe / vektor.length;
}

// D (using range sum function)

double mittelwert(in double[] vektor)
{
	return sum(vektor) / vektor.length;
}

-- 
Marco