• bobcat <a b.com> Mar 24 2008

bobcat <a b.com> writes:

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.