Re^2: "last expression" quiz

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Re^3: "last expression" quiz by bart (Canon) on Oct 19, 2005 at 22:27 UTC
A `for` loop typically returns nothing, whatever that means... Judging by your results on the warnings, or rather the lack of them, I think the subs return false, thus, `!1`. That is both equal to "" and numerically equal to 0 without a warning. Oh, and a 1 is allowed to be used as a statement without warning. Typical use for them is in a bodyless loop: `1 while COND;` [download] as well as as the last statement in a required file/module. Hence that there's no warning for a bare `1;`.	[reply] [d/l] [select]
Re^4: "last expression" quiz by Aristotle (Chancellor) on Oct 19, 2005 at 22:32 UTC
Actually, a `for` loop does return something. Assuming it runs at least once, it will return an empty string, alias scalar false. There seems to be no particular reason for that behaviour. Makeshifts last the longest.	[reply]
Re^5: "last expression" quiz by sauoq (Abbot) on Oct 19, 2005 at 22:36 UTC
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` [download] -sauoq "My two cents aren't worth a dime.";	[reply] [d/l] [select]
Re^6: "last expression" quiz by japhy (Canon) on Oct 19, 2005 at 23:12 UTC
Re^6: "last expression" quiz by Aristotle (Chancellor) on Oct 19, 2005 at 22:42 UTC
Re^7: "last expression" quiz by chromatic (Archbishop) on Oct 20, 2005 at 06:46 UTC
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Re^4: "last expression" quiz by Aristotle (Chancellor) on Oct 19, 2005 at 22:58 UTC
Oh, and another thing: you can use either 0 or 1 as a constant in void context without getting a warning, but you can also use any string that starts with `"ig"`, `"ds"`, or `"di"`, as Dominus famously demonstrated. Makeshifts last the longest.	[reply]
Re^4: "last expression" quiz by sauoq (Abbot) on Oct 19, 2005 at 22:44 UTC
as well as as the last statement in a required file/module. Well, you can use whatever you want as the last statement of a required module without getting the "Useless use of a constant in void context" warning. -sauoq "My two cents aren't worth a dime.";	[reply]
Re^5: "last expression" quiz by bart (Canon) on Oct 19, 2005 at 22:48 UTC
True, if you actually require the file. That probably is because then, the last statement isn't called in void context. But you do get the warning if you try to test such a module for syntax errors using `perl -wc FILE`. Unless you actually use 1.	[reply] [d/l]