... cease to exist as soon as you go to the next code line.

Indeed, it may cease to exist even before that, or rather, never come into existence in the first place. In the example below, the compiler doesn't even bother with the literal values. I suspect it only compiles  $var because it isn't smart enough to be sure there is no side-effect associated with the reference: maybe it's a tie-ed variable? Other kinds of compilers may be much more aggressive about eliminating such "dead code." 

c:\@Work\Perl\monks>perl -wMstrict -MO=Deparse,-p -le
"my $var = 42;
 (17, $var, 'a string');
 (137, 'd string');
"
Useless use of a constant (17) in void context at -e line 1.
Useless use of private variable in void context at -e line 1.
Useless use of a constant (a string) in void context at -e line 1.
Useless use of a constant (137) in void context at -e line 1.
Useless use of a constant (d string) in void context at -e line 1.
BEGIN { $^W = 1; }
BEGIN { $/ = "\n"; $\ = "\n"; }
use strict 'refs';
(my $var = 42);
('???', $var, '???');
('???', '???');
-e syntax OK

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In reply to Re^2: new to perl by AnomalousMonk
in thread new to perl by sudevshetty

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