... evaluates its left argument, throws that value away, then evaluates its right argument and returns that value.

McA: As e.g.:

c:\@Work\Perl\monks>perl -wMstrict -le
"sub foo { print 'hi from foo()'; }
 my $bar = 42;
 ;;
 my $agent = (foo(), $bar, 666, 99);
 print qq{agent $agent};
"
Useless use of private variable in void context at -e line 1.
Useless use of a constant (666) in void context at -e line 1.
hi from foo()
agent 99
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Note the  Useless use of ... warnings for the variable and constant as these are evaluated and thrown away. Perl understands that the evaluation of a subroutine may have (useful) side-effects.