The difference is that Example 2 (using parentheses) is correct and the others are broken.

Braces (i.e. { and }) are used (amongst other things) to create hash references. So...

 my %hash    = ( foo => 1, bar => 2 );
 my $hashref = { foo => 1, bar => 2 };

[download]
perl -E'sub Monkey::do{say$_,for@_,do{($monkey=[caller(0)]->[3])=~s{::}{ }and$monkey}}"Monkey say"->Monkey::do'

In reply to Re: Difference in Hash Declaration by tobyink
in thread Difference in Hash Declaration by perl@1983

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