Re^7: map in void context

No, not at all since you cannot equate calling an operator with a call to a subroutine.

Why not? What's so fundamentally different between the following two lines?

$y = CORE::abs($x);    # operator
$y = POSIX::abs($x);   # sub
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Would you even have known one was an operator and one wasn't had I not told you?

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Re^8: map in void context by pat_mc (Pilgrim) on Dec 22, 2008 at 11:00 UTC
ikegami - From a formal point of view there is, of course, a huge difference between calling a subroutine or using an operator - even if the difference is not discernable in Perl from their surface strings as you illustrate (other programming languages, of course, choose to handle this differently). I am not talking about how the input and output data get shifted around in memory here. The main difference from a formal perspective is that operators are part of the language inventory (its lexicon, to be precise) while subroutines are user-defined constructs based on language inventory and hence do not belong to the inventory themselves. As a result, operators may have additional properties - such as side-effects - associated with them by definition while subroutines do and cannot (as far as I am aware I cannot define side-effects for a subroutine in Perl). To come up with a uniform argument on the production of side-effects by Perl commands (not statements!) one may wish to argue that the side-effect of a subroutine call is identical to its return value ... this behaviour would permit (the meaningful?) generalisation that every construct in Perl involving an operator (be it Perl-internal or user-defined) and its operands returns its return value plus one or more side-effect(s).	[reply]
Re^9: map in void context by chromatic (Archbishop) on Dec 23, 2008 at 05:36 UTC
... as far as I am aware I cannot define side-effects for a subroutine in Perl.... It's easy: `use 5.010; sub square_a_number { my $value = shift; $Some::Global::Variable += $value; say "Squaring the value '$value'"; return $value * $value; }` [download] There are two trivial side effects, as well as the non-obvious side-effect of setting `SvNOK` on `$value`.	[reply] [d/l] [select]