Re^6: An iterator for (not "iterating") a recursive data structure.

To be fair, the semi predicate problem will still show up if you want an empty array to be a valid return value.

But there are ways to fix it:

return an array ref hence a scalar
throw an exception via die and catch it with eval block (or better Try::Tiny )
do a goto to an external label named FINISHED or similar (totally undervalued option)

Cheers Rolf
_{(addicted to the Perl Programming Language :)

Wikisyntax for the Monastery
FootballPerl is like chess, only without the dice}

Comment on Re^6: An iterator for (not "iterating") a recursive data structure.

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Re^7: An iterator for (not "iterating") a recursive data structure. by ikegami (Patriarch) on Jul 09, 2019 at 18:38 UTC
Are you you talking about iterators that return a possibly empty list of items? Just have it return an array reference!	[reply]
Re^8: An iterator for (not "iterating") a recursive data structure. by LanX (Saint) on Jul 09, 2019 at 21:09 UTC
Lol ... See first bullet point. Cheers Rolf _{(addicted to the Perl Programming Language :) Wikisyntax for the Monastery FootballPerl is like chess, only without the dice}	[reply]
Re^9: An iterator for (not "iterating") a recursive data structure. by ikegami (Patriarch) on Jul 11, 2019 at 12:09 UTC
My point still stands: The other two solutions are crazy!	[reply]