Tiny Perl puzzle

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Re: Tiny Perl puzzle by tobyink (Canon) on Jun 05, 2014 at 22:19 UTC
I realised fairly quickly that the plus would be treated as a unary operator, and thus assumed the whole thing would be effectively: `print two( 0==0 ? "true" : "false" );` [download] ... and thus Perl would die because there's no function `two()` defined. But how foolish of me!! The first `two` becomes a file handle of course, albeit an unopened one. So the whole line ends up printing to nowhere. Good puzzle. This sort of thing is precisely the reason various best practices have arisen. `use Moops; class Cow :rw { has name => (default => 'Ermintrude') }; say Cow->new->name`	[reply] [d/l] [select]
Re: Tiny Perl puzzle (duh) by tye (Sage) on Jun 06, 2014 at 00:22 UTC
This surprises any even moderately experienced Perl programmer? Update: It appears that my test didn't sufficiently accurately replicate the original program text. Though I admit this particular quirk didn't and doesn't bother me much as I avoid barewords exactly because they lead to lots of ambiguities. - tye	[reply]
Re: Tiny Perl puzzle by LanX (Saint) on Jun 06, 2014 at 00:35 UTC
not sure about the precedence my first guess is "true" my second 1 Can't test ATM :) Cheers Rolf (addicted to the Perl Programming Language) update tobyinc's analysis is correct! :) one more reason to enforce `use strict` and 'warnings'...	[reply] [d/l]
Re^2: Tiny Perl puzzle by Anonymous Monk on Jun 06, 2014 at 01:16 UTC
I wasn't even trying to guess what it would really parse as so I just Deparse and run it <Reveal this spoiler or all in this thread>	[reply] [d/l]
Re^3: Tiny Perl puzzle by davido (Cardinal) on Jun 06, 2014 at 18:43 UTC
I think B::Deparse gets it wrong -- as it sometimes does -- when you add `-p`: My theory: When Deparse tries to add parens wherever it can, it treats the first `two` as a function call (which was my first guess too). But as tobyink correctly surmised, that first `two` is treated by print as a filehandle. This is confirmed by the more low-level output of B::Concise: <Reveal this spoiler or all spoilers in this node or all in this thread> Dave	[reply] [d/l] [select]
Re^4: Tiny Perl puzzle by Anonymous Monk on Jun 07, 2014 at 07:25 UTC
Re^4: Tiny Perl puzzle by LanX (Saint) on Jun 07, 2014 at 15:38 UTC
Re^5: Tiny Perl puzzle by Anonymous Monk on Jun 08, 2014 at 09:17 UTC
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Re: Tiny Perl puzzle by locked_user sundialsvc4 (Abbot) on Jun 06, 2014 at 12:09 UTC
`print (two + two == five) ? ( user == politician) ? "Re-elect me and I will fix it." : "It's not a bug, it's a feature!" : (user == accountant) ? "What do you -want- the answer to be?" : "Don't worry, sonny, no child will be left behind.™" ;` [download]
Re^2: Tiny Perl puzzle by LanX (Saint) on Jun 06, 2014 at 13:31 UTC
Another incorrect Perl puzzle? (hint: `print` greedily loves brackets! :) Cheers Rolf (addicted to the Perl Programming Language)	[reply]
Re^2: Tiny Perl puzzle by Anonymous Monk on Jun 07, 2014 at 07:27 UTC
(Please mark spoilers accordingly.) sundialsvc4, why not honor the OPs request and use spoiler tags?	[reply]

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