Is it evaluation-order safe to match against a string in a variable and assign the result of that execution into the same variable? Similarly, is matching against a regex capture variable safe? In perl 5 all order of evaluation is undefined and while simple cases "work", I'm not sure whether this is sufficiently simple to not pose a problem.

$_ = q(5              <$> const(PV "{key}") s ->6\n);
/^(.*?<.> )([\w-]+|\S+)(.*?)$/ or next

# $1 == 19
# $2 eq "const"
# $3 eq '(PV "{key}") s ->6\n'

# Matching against $3
my $pv = ( $3 =~ /[INP]V ("?(?:\\"|[^"])*"?)/ )[0];

# Or matching against a variable and then assigning into it.
my $pv = $3;
$pv = ( $pv =~ /[INP]V ("?(?:\\"|[^"])*"?)/ )[0];

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In reply to Matching and order of evaluation by diotalevi

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