Re^5: "last expression" quiz

Actually, bart is saying it returns !1 which is really scalar false. It is subtly different than "" as can be seen here:

$ perl -wle 'print "yes" if !1 == 0 '
yes
$ perl -wle 'print "yes" if "" == 0 '
Argument "" isn't numeric in numeric eq (==) at -e line 1.
yes
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-sauoq
"My two cents aren't worth a dime.";

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Re^6: "last expression" quiz by japhy (Canon) on Oct 19, 2005 at 23:12 UTC
The difference is more visible this way: `use Devel::Peek; Dump(""); Dump(!1);` [download] The output of which is SV = PV(0x816d944) at 0x8163c48 REFCNT = 1 FLAGS = (PADBUSY,PADTMP,POK,READONLY,pPOK) PV = 0x8167830 ""\0 CUR = 0 LEN = 1 SV = PVNV(0x814d6a0) at 0x814c600 REFCNT = 2147483647 FLAGS = (PADBUSY,PADTMP,NOK,POK,READONLY,pNOK,pPOK) IV = 0 NV = 0 PV = 0x814d678 ""\0 CUR = 0 LEN = 1 Jeff `japhy` Pinyan, P.L., P.M., P.O.D, X.S.: Perl, regex, and `perl` hacker How can we ever be the sold short or the cheated, we who for every service have long ago been overpaid? ~~ Meister Eckhart	[reply] [d/l]
Re^6: "last expression" quiz by Aristotle (Chancellor) on Oct 19, 2005 at 22:42 UTC
Ah, interesting; I guess Perl DWIMs this so well I had never paid enough attention to notice the subtlety. Reminds me of the games some people played elsewhere on the Monastery quite a while ago with scalars that had specific, different values when evaluated as numbers or as strings (without overloading, if memory serves). (Alas, I cannot remember any useful keywords to Super Search it.) Makeshifts last the longest.	[reply]
Re^7: "last expression" quiz by chromatic (Archbishop) on Oct 20, 2005 at 06:46 UTC
Are you thinking perhaps of `dualvar()` from Scalar::Util?	[reply] [d/l]
Re^8: "last expression" quiz by Aristotle (Chancellor) on Oct 21, 2005 at 10:22 UTC
Yes, that’s precisely the kind of thing I’m talking about. The nodes I am thinking of predate Scalar::Util and instead used a bit of voodoo to achieve the effect, though. And thanks for pointing me that way – I didn’t know Scalar::Util had such a utility function. Plus now I see several new interesting functions in recent versions that I hadn’t noticed before. I need to do some homework here! Makeshifts last the longest.	[reply]