Supported in far future version?

Moron has asked for the wisdom of the Perl Monks concerning the following question:

In an idle moment, I checked if this would compile (I was using v5.6.1):

much: do ~0;
[download]

And this is the error it produced:

Perl v18446744073709551615.0.0 required--this is only v5.6.1, stopped 
+(did you mean v18446744073709551615.0.0?) at -e line 1.
[download]

Curiously, adding '. "\n" after the 0 made it compile ok. But having found nothing relevant in the documentation, it does make me wonder what is happening here.

Update: By experiment, ~0 seems to produce a large (max?) integer value. So it looks like it is behaving like a "require ~0;", which reduces the mystery while still being unexpected.

-M

Free your mind

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Re: Supported in far future version? by Mutant (Priest) on Dec 15, 2005 at 13:19 UTC
Unary ~ is the One's complement operator, which is why it's producing large integers.	[reply]
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Re: Supported in far future version? by blazar (Canon) on Dec 15, 2005 at 14:03 UTC
This doesn't happen with 5.8.6 here. Whatever, `~0` is binary complement of zero, i.e. indeed a "largish" integer (but not if you're on a 4 bit processor!;-). I do get the same behaviour if I `s/do/require/`, so it seems that your perl is interpreting do that way. Maybe checking some perldelta may reveal a change that has occured in the meanwhile. Try running your script through B::Deparse and maybe that could shed some light on how perl is interpreting it. `Perl v18446744073709551615.0.0 required--this is only v5.6.1, stopped +(did you mean v18446744073709551615.0.0?) at -e line 1.` [download] Hmmm... so you're on a 64-bit machine!! I don't... `$ perl -le 'print~0' 4294967295` [download]	[reply] [d/l] [select]
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Re: Supported in far future version? by ambrus (Abbot) on Dec 15, 2005 at 22:23 UTC
`much: do ~0;` compiles and runs and appears to do nothin with my perl. `require ~0;` however, produces this error: `Perl v4294967295.0.0 required (did you mean v4294967295.000?)--this is + only v5.8.5, stopped at -e line 1.` [download] To supress this message, try adding `use integer;` before the statement. :)	[reply] [d/l] [select]