The exact heuristics may be helpful in this meditation. Quoting from the perlop section on I/O Operators:
OTOH chester's observation, which comes completely unexpected to me, suggests that the observed behaviour may have little if anything to do with angular parens and thus that that heuristics may not be relevant at all.

In reply to Re^2: C<while> magic also working with glob(): intentional or not? by blazar
in thread C<while> magic also working with glob(): intentional or not? by blazar

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