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Re^2: Why isn't this a quine?

by hossman (Prior)
on Aug 02, 2009 at 23:48 UTC ( #785303=note: print w/replies, xml ) Need Help??


in reply to Re: Why isn't this a quine?
in thread Why isn't this a quine?

might as well make it psuedo-palandromy

hossman@coaster:~$ cat monk.pl seek DATA, 0, 0; print <DATA> __DATA__ print <DATA> seek DATA, 0, 0; hossman@coaster:~$ perl monk.pl seek DATA, 0, 0; print <DATA> __DATA__ print <DATA> seek DATA, 0, 0;

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[Corion]: Aaah - you should be able to do this with overload, but I would hit somebody really hard if they constructed objects that are true but the empty string, and you not knowing about the domain knowledge where this makes sense
[Eily]: you could tie a variable into not having the same value each time, if you like to make people who try to debug your code facepalm
[Corion]: perl -wle 'package o; use overload q("") => sub {warn "str"; ""}, bool => sub{warn "bool"; 1}; package main; my $o={}; bless $o => o; print "Yay" if ($o && !length($o))'
[Corion]: But people writing such code should document the objects they construct and why it makes sense for an object to be invisible as string while being true in a boolean context
[hippo]: That's equal parts clever and horrendous.
[Eily]: the overload version wouldn't return true with "$x" && !length $x though, I guess
[hippo]: The more I look at this code, the more $x is a plain old scalar and the more this condition will never be true. I'm calling it a bug at this point.
[hippo]: Thanks for your input which has soothed my sanity (a little)
[Corion]: Eily: Sure - if you force both things into stringy things, then you break that magic. But that would also mean that you changed the expression, as now $x = 0.00 will be true instead of false as it were before

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