array of hashes example fails - perl

Question

I have a problem with multi dimension arrays. I then tried a sample in the book Perl 4th edition, page 379, and that failed as well! Why?
#!/usr/bin/perl
use strict;
use warnings;
# example in manual page 379
# input from file containing: husband=fred pal=barney wife=wilma pet=dino
while ( <> ) {
next unless s/^(.*?):\s*//;
my $who = $1;
for my $field ( split ) {
(my $key, my $value) = split /=/, $field;
my $HoH{$who}{$key} = $value;
}
}
`

Answer 1

Useful trick for illustrative examples - you can in line __DATA__ at the end of your file, and use that.
Anyway, when I run your code, I get:
Global symbol "$key" requires explicit package name (did you forget to declare "my $key"?)
Global symbol "$value" requires explicit package name (did you forget to declare "my $value"?
You are also declaring %HoH badly - you shouldn't use that form, and instead:
my %HoH;
And also that regex - will skip your input text, because it's looking for : and your input doesn't contain any. I will assume that like should be prefixed with flintstone:.
So to simplify and give you something that works:
#! usr/bin/perl
use strict;
use warnings;
use Data::Dumper;
my %HoH;
while (<DATA>) {
next unless s/^(.*?):\s*//;
my $who = $1;
for my $field (split) {
my ( $key, $value ) = split /=/, $field;
$HoH{$who}{$key} = $value;
}
}
print Dumper \%HoH;
__DATA__
flintstone: husband=fred pal=barney wife=wilma pet=dino
This outputs the dumped HoH:
$VAR1 = {
'flintstone' => {
'husband' => 'fred',
'wife' => 'wilma',
'pal' => 'barney',
'pet' => 'dino'
}
};

Answer 2

Your code contains some syntax errors, and your input text is wrong (there is no :
Try this:
my %HoH;
while ( <DATA> ) {
next unless s/^(.*?):\s*//;
my $who = $1;
for my $field ( split ) {
my ($key, $value) = split /=/, $field;
$HoH{$who}{$key} = $value;
}
}
print Dumper \%HoH;
__DATA__
flintstones: husband=fred pal=barney wife=wilma pet=dino