Re^2: Which is your favourite cmt-deserving Perl feature?

jdhedden,
This idiom can bite viciously. This will assign the value of whatever() to $something if it has a false value. A false value doesn't necessarily mean undefined.

0
''
'0'
undef

Future Perl's will have a //= operator which means "defined or" but without a patch, if a defined but false value is valid - you need to write this more like $something = whatever() if ! defined $something

This is likely a good case to comment since when debugging having a reminder that defined false values may be overwritten.

Cheers - L~R

See What is truth? (Curiosity corner) for more details

Comment on Re^2: Which is your favourite cmt-deserving Perl feature?

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Re^3: Which is your favourite cmt-deserving Perl feature? by blazar (Canon) on Jul 22, 2005 at 10:17 UTC
This is likely a good case to comment since when debugging having a reminder that defined false values may be overwritten. You're perfectly right. But, if one is aware of what he is doing `\|\|=` does its job most of the time. Of course we all will welcome `//=` to cover the remaining cases. Occasionally I use `\|\|=` on purpose to overwrite a false value (with another "standardized" false value), e.g.: `$u \|\|= ''; # or $v \|\|= 0;` [download] (Most often this is not necessary either, and -as usual- there are other ways to do it...)	[reply] [d/l] [select]

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Re^3: Which is your favourite cmt-deserving Perl feature?
by blazar (Canon) on Jul 22, 2005 at 10:17 UTC

This is likely a good case to comment since when debugging having a reminder that defined false values may be overwritten.

perfectly right

||=

//=

Occasionally I use ||= on purpose to overwrite a false value (with another "standardized" false value), e.g.:

$u ||= '';
# or
$v ||= 0;
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