Using map instead of iteration

[Don]

bearophile wrote:
> Russel Winder:
> 
>> Perhaps this needs review.  All modern language now have this as an
>> integral way of describing a sequence of values.
> 
> We have discussed about this not too much time ago. See the enhancement request:
> http://d.puremagic.com/issues/show_bug.cgi?id=5395
> 
> D language design is too much un-orthogonal about this, and I'd like to see this situation improved.
> 
> Currently there are several separated syntaxes and means to specify an interval:
> 
> 1) foreach interval syntax, no stride allowed and the interval is open on the right:
> 
> foreach (i; 0 .. 100)
> 
> 
> 2) Using iota, a badly named range, for intervals open on the right, it supports an optional stride:
> 
> foreach (i; iota(100))
> 
> 
> But empty intervals have different semantics. This runs with no errors, the foreach doesn't loop:
> 
> void main() {
>     foreach (i; 0 .. -1) {}
> }

Looks like a bug to me.


> 3) The switch range syntax, it uses two dots still, it's closed on the right:
> 
> import std.range;
> void main() {
>     char c = 'z';
>     bool good;
>     switch (c) {
>         case 'a': .. case 'z':
>             good = true;
>             break;
>         default:
>             good = false;
>             break;
>     }
>     assert(good);
> }

But the syntax is NOT case a..b, it's case a .. case b.
a..b always has intervals open on the right. There are no exceptions.