No such pseudo-hash field "HASH(0x10a57c)" at ./listref line 22.

##</code><code>##

my @bar = sort {$a->{blah} cmp $b->{blah} } @$foo;

##</code><code>##

my $foo = [ {blah=>5,d=>1},
            {blah=>4,d=>2},
            {blah=>3,d=>3},
            {blah=>2,d=>4},
            {blah=>1,d=>5}];

my @bar = sort {$a->{blah} cmp $b->{blah} } @$foo;

print join(',',map {$_->{blah}} @bar), $/;


##</code><code>##

my $foo = [ [5,1],
            [4,2],
            [3,3],
            [2,4],
            [1,5]];

my @bar = sort {$foo->{$a} cmp $foo->{$a} } @$foo;
# should be my @bar = sort {$a[0] cmp $b[0]} @$foo;

##</code><code>##

Can't coerce array into hash at ./listref line 33.