# from Scalar::Util

sub UNIVERSAL::a_sub_not_likely_to_be_here { ref($_[0]) }

sub reftype ($) {
  local($@, $SIG{__DIE__}, $SIG{__WARN__});
  my $r = shift;
  my $t;

  length($t = ref($r)) or return undef;

  # This eval will fail if the reference is not blessed
  eval { $r->a_sub_not_likely_to_be_here; 1 }
    ? do {
      $t = eval {
      # we have a GLOB or an IO. Stringify a GLOB gives it's name
      my $q = *$r;
      $q =~ /^\*/ ? "GLOB" : "IO";
    }
    or do {
      # OK, if we don't have a GLOB what parts of
      # a glob will it populate.
      # NOTE: A glob always has a SCALAR
      local *glob = $r;
      defined *glob{ARRAY} && "ARRAY"
      or defined *glob{HASH} && "HASH"
      or defined *glob{CODE} && "CODE"
      or length(ref(${$r})) ? "REF" : "SCALAR";
    }
    }
    : $t
}
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