Check whether a range is empty

[Ali Çehreli]

First, please show us code that demonstrates the issue.

On 07/14/2018 07:47 AM, vino.B wrote:

 >    The reason it never prints the text "Empty" is that the out of the
 > "r" is just an empty array.
 >
 > OUTPUT:
 > []
 > []

If that's the output of r, then r is not empty but has two elements and 
those elements are likely arrays. If they are in fact arrays, them being 
empty does not change r: it still has two elements.

If you want to treat the range as empty when all its elements are empty, 
then perhaps your problem needs std.algorithm.joiner. The following 
program demonstrates your issue with the first assert and the fix with 
the second assert:

import std.algorithm;
import std.range;

void main() {
     int[][] r = [ [], [] ];
     assert(!r.empty);
     auto joined_r = r.joiner;
     assert(joined_r.empty);
}

joiner joins elements that are ranges themselves. For example, joiner([ 
[1], [2] ]) is equal to [ 1, 2 ].

Ali