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The latest version of the book is P2.0, released 3 months ago. If you've bought a PDF of the book and would like to update it to this version (for free), visit your home page.

By default this page displays the errata for the latest version of the book. If you have a previous version, select it here:

If you've found a new error, please submit it.

  • Typo
  • Tech. error
  • Suggestion
  • Maybe next edition
  • Not a problem
  • Reported in: P2.0 (12-Dec-19)
PDF page: 8
In the topic "DRY - The Evils of Duplication", in the subtopic "DRY Violations in Data", there is a non formatted code. I am not sure whether it was t...more...
  • Reported in: P2.0 (11-Nov-19)
PDF page: 315
2 typo i think: in page 315 1 ovicide, 187 there is no "ovicide" in page 187 in page 316 Program Evaluation Review Technique, see PERT"T...more...
  • Reported in: P2.0 (29-Nov-19)
Paper page: 79
In the `` example script: The regex used to find import statements is ` '^import ', which will match lines that begin with `import`. B...more...
  • Reported in: P2.0 (18-Dec-19)
PDF page: 120

In update_customer() function, you forgot to add write_customer() function after changing the balance. Minh Luan

  • Reported in: P2.0 (13-Nov-19)
  • Fixed: 17-Jan-20, awaiting book release
Paper page: 134
"Don't chain method calls" tip should really be expanded out more or be removed. With the revitalization of functional programming, chaining becomes ...more...
Dave Thomas says: The discussion in the book is in the context of OO languages, where chaining means objects are passed around. In functional languages, pipelines pass values, divorced from the functions themselves, so the issue is different (although still there).
  • Reported in: P1.0 (13-Nov-19)
Paper page: 151

PG 151, Footnote 5, typo in name of the language

... Isobelle/ML ... ->
... Isabelle/ML ...--William Denman

  • Reported in: P1.0 (09-Jan-20)
Paper page: 233
It looks like something when wrong when formatting a code block, on page 233 about Ruby The code: $SAFE = 1 puts "Enter a file name to count: "...more...
  • Reported in: P2.0 (30-Oct-19)
  • Fixed: 17-Jan-20, awaiting book release
PDF page: 238
in Note 18 "If you’re seeing this in black and white and want the color version, or if you’re having trouble distinguishing colors and want to try th...more...
Dave Thomas says: Effectively, the book version is grayscale (although technically it is dither black and white).