Range Type
bobcat
a at b.com
Mon Mar 24 19:52:18 PDT 2008
Nice! I was also wishing for ranges in D, but didn't know how it would behave with the rest of the languages.
Doing foreach(i, 1..20) would also be a natural fit for this, where foreach also accepts a slice :). ( I know there is already something similar in D 2.0. )
Janice Caron Wrote:
> I know this has cropped up before (in discussions about multiple
> dimension arrays), but adding a range type would also really help with
> the whole business of returning slices. (See the many other threads
> currently buzzing with this topic).
>
> A range is nothing more than a two-element struct
>
> struct Range(T,U=T)
> {
> T begin;
> U end;
> }
>
> However, if you throw in some extra language support, it gets really,
> really useful. Basically, you want the ".." infix operator always to
> create a range. Thus
>
> auto x = 3 .. 4;
>
> creates a Range!(int) with values { 3, 4 }. In general (a .. b) should
> evaluate to a Range!(typeof(a),typeof(b)) with values { a, b }.
> Finally, you also want [] and opSlice() to accept Range! parameters,
> so that
>
> s = s[a..b];
>
> can always be rewritten as
>
> auto t = a..b;
> s = s[t];
>
> In general, opSlice(Range r) should be eqivalent to opSlice(r.begin, r.end).
>
> In my opinion language support for ranges (allowing .. to return a
> range, and allowing [] to accept a range) has advantages above and
> beyond those already discussed, and may also allow many other exciting
> possibilites we haven't even thought of yet.
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