Bravo! (Just what I was thinking).
However, as an alternative to using no warnings 'uninitialized' (always appear as though you thought of everything), try OR-ing the hash values with 0, like this:
my %time=reverse split(/([HMS])/, '5H3M17S');
my $time = (( (($time{H}||0) * 60) + ($time{M}||0)) * 60) + ($time{S}|
+|0);
dmm
| [reply]
[d/l]
[select] |
I have to disagree. I think no warnings 'uninitialized' is a much more elegant way to avoid those idiotic warnings. For one thing, they shouldn't be warnings in the *first* place. In this example, the expression that triggers the warning is:
60 * undef
Why should this cause a warning? The behavior is well-defined, documented, rational, and well understood. I don't think perl should be warning me about this since it is a feature of Perl!
Your solution (nothing personal, its a common workaround) converts the above expression to:
60 * (undef || 0)
Which doesn't spew out a warning... The question is why not? If the first one gives me a "Use of uninitialized value in multiplication" error, why wouldn't this give me
a "Use of uninitialized value in logical OR" error? Its not like undef in boolean context is more well-behaved than in numeric context1. Why should one throw a warning and the other not... Either both should trigger warnings and we sprinkle lots of defined() calls everywhere, or neither should.
Adding gratuitous logic to avoid spurious warnings doesn't agree with me. Better just to turn those specific warnings off and be done with it.
1I know thats splitting hairs, but the fact that it is splitting hairs is kind of my point anyway.
-Blake
| [reply]
[d/l]
[select] |
Why should this cause a warning? The behavior is well-defined, documented, rational, and well understood. I don't think perl should be warning me about this since it is a feature of Perl!
Because using undef in a math operation is generally a Weird Thing, and by turning on warnings you've asked Perl to warn you about Weird Things.
If the first one gives me a "Use of uninitialized value in multiplication" error, why wouldn't this give me a "Use of uninitialized value in logical OR" error?
The reason is that logical or is often used as a defaulting operator. That idiom--$foo||$default--is so common that it's getting its own syntax in Perl 6--the new // defaulting operator, which only returns the right operand if the left operand is undefined. With this addition to Perl 6 perhaps the warning you mention will appear.
PS Sorry if this has the tone of lashing out angrily at you or something. It's probably too late for me to be safely posting to the Monastery anyway... :^)
=cut
--Brent Dax
There is no sig.
| [reply]
[d/l]
[select] |
| [reply]
[d/l] |