G'day Bod,

It hadn't occurred to me when reading earlier posts referring to "old syntax", but your use of "modern syntax" made me wonder how much older $$hashref{key} was compared to $hashref->{key}.

The oldest Perl version available via the online "Perldoc Browser" is for "Perl 5.005". Poking around in various parts of that (perlop, perldsc, and others) I see both forms being used without any mention of one being newer. I'm happy to be proven wrong, but I rather suspect that both have been available since Perl 5.000.

Without the arrow (dereferencing) operator, it's easy to make mistakes, especially with complex data structures. This is discussed in "5.005: perlref: Using References"; this information is retained in "5.36.1: perlref: Using References".

Except in the simplest of cases, I'll always prefer the $hashref->{key} form, as I find it both easier to read and less error-prone. I can't think of any situation where the $$hashref{key} form is "required".

In closing, it's probably worth noting "Postfix Dereference Syntax" and "Postfix Reference Slicing". These are newer syntaxes. I prefer them; I acknowledge that others don't. There's an example of the former in my reply to the OP.

— Ken

In reply to Re^3: Reading session data by kcott
in thread Reading session data by PeterKaagman

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