Excellent! - Many thanks, ysth - that worked great!

  # Replace @closures usage by this line in "sub map_With_Closure"
  &$sub(   map {my $x=$_; +sub:lvalue{$x->[0]}  }@_   );
  # "+" required in front of sub, to avoid perl's mininterpration
  #   of "sub" being a label, and attribute-- thanks ysth!
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The only minor gripe with this code is that it requires the use of the temporary variable $x , since $_ is local to the lvalue sub, and does not inherit from the "map".