my $method1 = '(($a && $b)) || ($c && $d)';
my $method2 = sub { my ($a,$b,$c,$d) = @_; (( $a && $b )) || ($c && $d) }; };
sub method3 { ... }

print "yeah\n" if eval $method1; die $@ if $@;
print "yeah\n" if $method2->($a,$b,$c,$d);
print "yeah\n" if method3(...);