This page lists the errata in page order, whereas the blog will issue new errata notices as and when they are discovered.

Thanks very much to Greg Bowen, Christian Fricke, Daniel Kröni, Patrick Lynch, Hua Ming, Joshua Nahum and Carlos Suberviola Oroz for pointing out these errors.

Page 51

The definition of max' says:

    max' x yMax

it should be:

    max' x y

Pages 56 and 111

These pages contain  examples of using

    read

to turn a string into a value. If you type these to the ghci prompt then a type annotation is needed, but that’s not always true in general, as seen in the example here:

    Prelude> (read "True") && False

    False

where the context of the read expression supplies the required type.

Page 72

The image at the start of Section 4.2 should be as below. This image is also referred to by Exercises 4.5 to 4.7.

   

Page 97

In the introductory section to Chapter 5,  “ … list processing functions, aw well as … “ should be “ … list processing functions, as well as … “.

Page 182

Line 11 refers to

    (inputDiff.1)

this should be:

    (inputDiff)

Page 182

Line 8 refers to ‘different’; it should say ‘difference’.

Page 191

Line -1 ‘jusy’ should say ‘just’.

Page 192

In the definition of playInteractive we use the “as pattern”

    t@(mine,yours)

which has the same effect as using the pattern (mine,yours) but also matching the whole pattern by t. This notation is explained in detail in the box on p384.

Page 208

The final equation in this exercise should read

    flipH (flipH pic) = pic

Page 208

The output at the foot of the page should be "Freak Out !" not "Freak Out!"

Page 231

The second last paragraph is missing a "we": ...setting the scene for Chapter 12 where _ will put these...

Page 232

The fourth paragraph contains an unfinished sentence:  ... passing the output of one to the input of another, and it is _. Should stop after “another” with a full stop.

Page 235

The function mentioned here should be

    produceBill

as discussed at the foot of page 148.

Page 268

Word correction from you to your: “Hint: you may want to model you(r) definition”.

Page 269

The exercise asks you to write a function

    train :: Moves -> [Strategy] -> Strategy

this should be:

    train :: [Move] -> [Strategy] -> Strategy

Page 271

The function type given here should be

    splits :: [a] -> [([a],[a])]

Page 390

The function addMessage should be defined like this

    addMessage im (QS time serv ml)

      | isYes im            = QS time serv (ml++[im])

      | otherwise           = QS time serv ml

        where

        isYes (Yes _ _)     = True

        isYes _             = False

so that “No” messages are not included in the queue, since the queueStep function doesn’t process them.

Page 394

The API for search trees here is missing the function of checking whether a value is an element of the tree:

    elemT :: Ord a => a -> Tree a -> Bool