with_cache_cleared_do { some_sub_requesting_the_data; };


##</code><code>##

use strict;
use warnings;

{ #--- confine flag in lexical scope
  my $refresh_request_flag;

  #--- use closures to access flag
  sub refresh_requested {  return !! $refresh_request_flag  }

  sub with_cache_cleared_do (&) {
    $refresh_request_flag = 1;
    my @result            = shift->();  # run block
    $refresh_request_flag = 0;

    return unless defined wantarray;
    return wantarray ? @result : $result[0];
  }

}
# usage: -run:   with_cache_cleared_do {  some block  };
#        -check: refresh_requested()


#--- that's it - now the tests ...
use Test::Simple tests => 6;

ok( ! refresh_requested()              , 'before: flag is cleared' );

with_cache_cleared_do {  ok( refresh_requested() , 'flag set within block' ); };

ok( ! refresh_requested()              , 'after:  flag is cleared again' );

sub nested {
  ok( ( $_[0] == 42 and refresh_requested() ),
      'flag set within nested calls with parameters')
}
with_cache_cleared_do {  nested( 42 )  };

my $x = with_cache_cleared_do {  return 'foo'; };
ok ( $x eq 'foo'                      , 'result in scalar context' );

my @x = with_cache_cleared_do {  return ( 'one', refresh_requested() ); };
ok( ( $x[0] eq 'one' and $x[1] == 1 ) , 'result in list context' );