Re: Do people find warning for undef with string compare useful?

It is often annoying, though in some cases is does help find bugs.

I don't like introducing "if defined" checks, as they blow up the code size and make it less readable. Luckily the // operator provides a slightly more concise solution that can be use in many (but not all!) situations where you want to do string-comparison on a variable that may be undef:
Instead of...

if ($possibly_undef eq 'Hello') { ...
[download]

...write:

if ($possibly_undef//'' eq 'Hello') { ...
[download]

Or of course "no warnings 'uninitialized';" if you want to disable it completely, but I don't usually do this.

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Re^2: Do people find warning for undef with string compare useful? by choroba (Cardinal) on May 31, 2013 at 22:12 UTC
Unfortunately, // has lower priority than `eq`. You code is equivalent to `if ($possibly_undef) { ...` [download] The correct syntax is `if (($possibly_undef // '') eq 'Hello') { ...` [download] Which blows up the code size and makes it less readable. لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ	[reply] [d/l] [select]
Re^3: Do people find warning for undef with string compare useful? by smls (Friar) on May 31, 2013 at 22:41 UTC
Ah yes, you're right of course.	[reply]