Errata

Errata for Understanding Computation

Submit your own errata for this product.

The errata list is a list of errors and their corrections that were found after the product was released.

The following errata were submitted by our customers and have not yet been approved or disproved by the author or editor. They solely represent the opinion of the customer.

Color Key: Serious technical mistake Minor technical mistake Language or formatting error Typo Question Note Update

Version	Location	Description	Submitted by	Date submitted
PDF	Page 11 United States	Great book! There are hardly any errors in it, which I appreciate. I did find one minor issue when I went back to the "Just Enough Ruby" section just now. Page 11 describes behavior for map and flat_map that unfortunately no longer works because the "chars" method now returns an Enumerable, which has a different to_s and inspect. To get your output, one would have to change the commands or override to_s or inspect. Examples in 1.9.3: irb(main):008:0> ['one', 'two', 'three'].map(&:chars) => [#<Enumerator: "one":chars>, #<Enumerator: "two":chars>, #<Enumerator: "three":chars>] irb(main):005:0> ['one', 'two', 'three'].map(&:chars).map(&:to_a) => [["o", "n", "e"], ["t", "w", "o"], ["t", "h", "r", "e", "e"]] irb(main):009:0> ['one', 'two', 'three'].flat_map(&:chars) => [#<Enumerator: "one":chars>, #<Enumerator: "two":chars>, #<Enumerator: "three":chars>] irb(main):010:0> ['one', 'two', 'three'].map(&:chars).flat_map(&:to_a) => ["o", "n", "e", "t", "w", "o", "t", "h", "r", "e", "e"]	Stephen Dewey	Dec 22, 2013
Printed	Page 32 First paragraph	Hi Tom, Awesome book! Required reading for everyone on my dev. team. I think Object.send(:remove_const, :Machine) can be avoided by Machine = Struct.new(...) do ... end Is there a reason why the book uses class Machine < Struct.new(...) Thanks, Rohit	Rohit Namjoshi	Aug 31, 2013