At 08:37 PM 4/16/01 +0100, Nic LAWRENCE wrote:
>Thought I'd have a go at securing one of my scripts after Ray's question
>about security. When using "strict", I am told the following:
>
>Scalar value @views_keys[$k] better written as $views_keys[$k] at
>./newremote2.pl line 327.
>Scalar value @_[0] better written as $_[0] at ./newremote2.pl line 342.
>Scalar value @cview_cams[0] better written as $cview_cams[0] at
>./newremote2.pl line 346.
>Scalar value @_[0] better written as $_[0] at ./newremote2.pl line 359.
>
>I'm curious to know why for example something like @cview_cams[0] would be
>better written as $cview_cams[0]?
You're unintentionally using a slice, thereby imposing a list context where
you'd probably expect a scalar context.
>If there's an faq which tells me WHY then
>if someone could point me to that I'd be very happy. ;-)
Inserting "use diagnostics" or running the message through splain, or
looking the message up in perldiag, would reveal the reason:
Scalar value @%s{%s} better written as $%s{%s}
(W) You've used a hash slice (indicated by @) to select a single element of
a hash. Generally it's better to ask for a scalar value (indicated by $).
The difference is that $foo{bar} always behaves like a scalar, both when
assigning to it and when evaluating its argument, while @foo{bar} behaves
like a list when you assign to it, and provides a list context to its
subscript, which can do weird things if you're expecting only one subscript.
--
Peter Scott
Pacific Systems Design Technologies
