Errata for Learning Perl Objects, References, and Modules

"Controlling the Distribution withMakefile.PL" NOW READS: "Controlling the Distribution with Makefile.PL"

do "navigate.pl"

"Welcome to next step in your understanding of Perl." NOW READS: "Welcome to the next step in your understanding of Perl."

"Suppose navigate.pl ..."

require "navigate.pl";

"This means that even if navigate.pl ..." Page 9:

require "navigate.pl";

navigate.pl

It appears that the file "navigation.pl" has been mistakenly renamed "navigate.pl" in all the references to it on pages 8 and 9. Page 8:

turn_toward_heading(compute_heading_to_island()); NOW READS: turn_towards_heading(compute_heading_to_island());

navigation_turn_toward_heading(compute_heading_to_island()); NOW READS: navigation_turn_towards_heading(compute_heading_to_island());

turn_towards_port() NOW READS: turn_toward_port()

turn_towards_port() NOW READS: turn_toward_port()

Navigation::turn_toward_heading(compute_heading_to_island()); NOW READS: Navigation::turn_towards_heading(compute_heading_to_island());

@homeport = (21.1, -157.525); NOW READS: @homeport = (21.283, -157.842);

(Trivia note: 21.1 degrees north, 157.525 degrees west is the location... NOW READS: (Trivia note: 21.283 degrees north, 157.842 degrees west is the location...

turn_towards_port() NOW READS: turn_toward_port()

@homeport = (21.1, -157.525); NOW READS: @homeport = (21.283, -157.842);

$third_reference_skipper NOW READS: $third_reference_to_skipper

if ($reference_to_skipper = = $second_reference_to_skipper) { print "They are identical references. "; NOW READS: if ($reference_to_skipper == $second_reference_to_skipper) { print "They are identical references. ";

The title of the data structure on the right should be @data2, not @data1.

"anonymous hash" NOW READS: "anonymous array"

"Thus, you cam rewrite the roster creation as:" NOW READS: "Thus, you can rewrite the roster creation as:"

$totalbytes NOW READS: $total_bytes

Professor: By my calculations, you must be Gilligan! "; Professor: By my calculations, you must be Skipper! "; NOW READS: Professor: By my calculations, you must be Gilligan! Professor: By my calculations, you must be Skipper!

"Object-oriented programming (often called OOP) helps programmers run code sooner and maintain it easier at the cost of making the resulting programs slower." should be: "Object-oriented programming (often called OOP) helps programmers run code sooner and maintain it more easily at the cost of making the resulting programs slower."

"If your whole program is only be a couple hundred lines of code, using objects is probably a waste." should be: "If your whole program is only a couple hundred lines of code, using objects is probably a waste."

"Animal::speak,." should be "Animal::speak."

The code says: sub color { my $shift; it should be: sub color { my $self = shift;

The first two occurrences of the word "goto" are constant width, and the last two are normal typeface.

"indicies" should be: "indices"

At the end of the second (last) sentence in this paragraph, the name of the module subroutine is misspelled; it says "Ooogaboogoo::date::day" but is should read: Oogaboogo::date::day

The simplified solution suggests this assignment: $tb = $total_bytes{$source}; This causes $tb to contain a hash reference, so the arrow operator needs to be used: my @destinations = sort { $tb{$b} <=> $tb{$a} } keys %$tb; should be: my @destinations = sort { $tb->{$b} <=> $tb->{$a} } keys %$tb; and print "$source: $tb{$all} total bytes sent "; should be: print "$source: $tb->{$all} total bytes sent ";

print " $source => $destination: $tb{$destination} bytes "; it should be: print " $source => $destination: $tb->{$destination} bytes "

"In Chapter 9, you learned" should read "In Chapter 11, you learned"