I'm seeing behavior I wouldn't expect from the following code:

#!/usr/bin/perl -w
use Data::Dumper qw( Dumper );
use strict;

sub mycode {
  my $var = $_[0];
  defined($var) ? print qq|mycode() called with $var\n|
                : print qq|mycode() called with no operands.\n|;

  my $foo = "blah" if $var; # does $foo become static here?

  print "foo is $foo\n" if $foo;
  $foo ||= "FOO";
}

mycode("test");  # "foo is blah"
mycode();        #
mycode();        # "foo is FOO"
mycode();        # "foo is FOO"

# print Dumper(\%main::);  # make sure $foo is never in symbol table
[download]

I get this output:

mycode() called with test
foo is blah
mycode() called with no operands.
mycode() called with no operands.
foo is FOO
mycode() called with no operands.
foo is FOO
[download]

but I would expect this output:

mycode() called with test
foo is blah
mycode() called with no operands.
mycode() called with no operands.
mycode() called with no operands.
[download]

Somehow the variable $foo gets the value 'FOO' on the second call of mycode(). This seems to persist as seen in the third and fourth calls of mycode(). Can anyone explain this?

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