Just to hammer the point home even more - your second example is identical to

#!/usr/bin/perl
$barbaz = "something here";
foo("bar", "baz");

sub foo {
   $name = join('', @_);  # Build varname
   print $main::{$name}, "\n";
}
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In other words, you're using a hash - the package's symbol table. However, if you don't want to clobber something, use your own hash.