Put more simply, most languages assume the existence of command line arguments in an array, which eliminates the overhead of using the language or system libraries to process input for the test.

That does treat some languages more fairly, but it's not really reflective of any real world condition. You might as well begin by having the language explicitly set an array or variable with a specified input.

Side note on the closures bit -- a better, practical closures example is probably some sort of argument currying.

sub first_n_chars {
  my $n = shift;
  return sub {
    return substr( shift, 0, $n )
  };
}

my $first_4 = first_n_chars(4);

print $first_4->("hello world");
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