macro statement_control:<my_while>($expr, &whileblock) {
  while $expr &whileblock();
# do we need while $expr do &whileblock();    ?
}

my $i = 0;
my_while {$i < 10} {
  say "i: $i";
  my $j = 0;
  my_while {$j < 10} {
    say "j: $j";
    $j++;
  }
  $i++;
}

##</code><code>##

sub my_while(Code &expr, Code &whileblock) {
  while &expr() &whileblock();
}

##</code><code>##

use strict;
use warnings;

sub my_while(&&){
  my($expr, $whileblock) = @_;
  while(&$expr()){
    &$whileblock();
  }
}

my $i = 0;
my_while sub {$i < 10}, sub {
  print "i: $i\n";
  my $j = 0;
  my_while sub {$j < 10}, sub {
    print "j: $j\n";
    $j++;
  };
  $i++;
};