I was running some code today with warnings on (using 5.8.8) and I noticed something new.

I did not know that the following code was correct: 

use strict;
use warnings;

sub bob
{
    if (!(my $t = shift)) {
        warn "data is false\n";
    } elsif ($t eq 'a') {
        warn "a\n";
    } elsif ($t eq '1') {
        warn "one\n";
    } else {
        warn $t;
    }
}

bob();
bob(1);
bob('a');
bob('c');

[download]
I had thought that the scope of $t was only the if block and did not extend to the else blocks. Of course it makes perfect sense now. I just thought I would mention it here on the off chance that there is some other perlmonk as ignorant as me.

BTW I noticed this because I was running with use warnings, something I don't normally do.

UPDATE: [Thilosophy]
I got a warning because I had: 

if (my $a = $c) {
    #...
} elsif (my $a = $b) {
    #...
}

[download]
This gives the warning: 
"my" variable $a masks earlier declaration in same scope at ...
-- gam3
A picture is worth a thousand words, but takes 200K.

In reply to Duh. 'my' scope in if else blocks. by gam3

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.