1. Yes, they are equivalent. Parens are only needed if you have a list of scalar variables you want to assign from the first elements of @_.
  2. $config is assigned from a hash reference. The curlies produce one in that context.
  3. Also equivalent, fat comma ('=>') takes care of quoting the preceeding bare word.
  4. Because $config is a reference.

See tye's References quick reference.

After Compline,
Zaxo

In reply to Re: Perl data types and references by Zaxo
in thread Perl data types and references by thierry

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