Well I ran into this construct that doesn't do what I expect. Is Perl's behavior justified? If so, please help me understand. 
#!/local/bin/perl -w
use warnings;
use strict;

# Runs the sub reference in arg #1
sub Doit
{
&{$_[0]};
}

# Start of a big block - don't want to pollute
{
my $x = 777;
my $y = 222;

print "Initialized, what's the values?";
print " x = $x\n";
print " y = $y\n\n";

sub mysub
    {
    print "  Start of subroutine\n";
    print "    what's x? (forget y for now)\n";
    print "    x = $x\n\n";
    print "    Going to child block\n";
    print "     let's inspect the variables again:\n";
        {
        Doit( 
            sub { 
            print "x = $x\n\n"; 
            print "      y = $y\n\n"; } );
        }
    }
}
# Big Block 
mysub();

[download]
---------------------- output: 
>perl perlbug.pl
Initialized, what's the values? x = 777
 y = 222

  Start of subroutine
    what's x? (forget y for now)
    x = 777

    Going to child block
     let's inspect the variables again:
x = 777

Use of uninitialized value in concatenation (.) or string at perlbug.pl line 31

      y =
(This behavior has been checked on Perl 5.6.1 and 5.8.8)

In reply to Lexical Scoping and Anonymous Subroutines Passed To Functions by Anonymous Monk

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.