PragProg Customers

Effective Haskell: Omitted essential code lines (ch. 5, p. 198, pdf, P1.0)

vvnurmi

vvnurmi

Effective Haskell: Omitted essential code lines (ch. 5, p. 198, pdf, P1.0)

@RebeccaSkinner

On page 198, when phantom types are introduced, when listing other changes to the code example at hand, also this necessary change (adding the type parameter a) should be mentioned:

users :: [User a]

Without it the code won’t compile. The change is visible a couple pages later in the full final listing, but it’s confusing to the reader (me) that it wasn’t mentioned earlier.

View thread on forum
#errata/book-effective-haskell
0 12 0

Where Next?

View thread on forum
View Effective Haskell's book portal
Post errata for this book
Post a suggestion for this book
Post a question about this book
Post a review about this book
Home PragProg Customers
#errata/book-effective-haskell
0 12 0
Last post

Popular Pragmatic Bookshelf topics Top

herminiotorres
PragProg Customers

Concurrent Data Processing in Elixir: various errata
Hi @Margaret , On page VII the book tells us the example and snippets will be all using Elixir version 1.11 But on page 3 almost the en...
#errata/book-concurrent-data-processing-in-elixir
15 1549 13
New
cro
PragProg Customers

Programming Phoenix LiveView: P27, live_path confusion
I am working on the “Your Turn” for chapter one and building out the restart button talked about on page 27. It recommends looking into ...
#question/book-programming-phoenix-liveview
7 3505 14
New
curtosis
PragProg Customers

Build a Weather Station with Elixir and Nerves: 'mix deps.get' does not work if user has not created a keyfile (page 16)
Running mix deps.get in the sensor_hub directory fails with the following error: ** (Mix) No SSH public keys found in ~/.ssh. An ssh aut...
#errata/book-build-a-weather-station-with-elixir-and-nerves
2 1457 3
New
jskubick
PragProg Customers

Kotlin and Android Development featuring Jetpack: $kotlin_version ? (page 8)
I’m running Android Studio “Arctic Fox” 2020.3.1 Patch 2, and I’m embarrassed to admit that I only made it to page 8 before running into ...
#errata/book-kotlin-and-android-development-featuring-jetpack
0 1698 3
New
fynn
PragProg Customers

Build a Weather Station with Elixir and Nerves: SGP30 vs SGP40
This is as much a suggestion as a question, as a note for others. Locally the SGP30 wasn’t available, so I ordered a SGP40. On page 53, ...
#suggestion/book-build-a-weather-station-with-elixir-and-nerves
0 1292 2
New
nicoatridge
PragProg Customers

Kotlin and Android Development: Could not get unknown property ‘kotlin_version’…
Hi, I have just acquired Michael Fazio’s “Kotlin and Android Development” to learn about game programming for Android. I have a game in p...
/book-kotlin-and-android-development-featuring-jetpack
0 8095 6
New
jskubick
PragProg Customers

Kotlin and Android Development featuring Jetpack: android:tint vs app:tint (chapter 7, p186)
I found an issue in Chapter 7 regarding android:backgroundTint vs app:backgroundTint. How to replicate: load chapter-7 from zipfile i...
#errata/book-kotlin-and-android-development-featuring-jetpack
0 3566 3
New
digitalbias
PragProg Customers

Build a Weather Station with Elixir and Nerves: Problem connecting to Postgres with Grafana
Title: Build a Weather Station with Elixir and Nerves: Problem connecting to Postgres with Grafana on (page 64) If you follow the defau...
#errata/book-build-a-weather-station-with-elixir-and-nerves
0 1962 4
New
kevinjyh
PragProg Customers

Python Testing with pytest, Second Edition:Abou epub format
Is the book’s epub format available to read on Google Play Books?
#question/book-python-testing-with-pytest-second-edition
0 1126 3
New
EdBorn
PragProg Customers

Agile Web Development with Rails 7: (page 70)
Title: Agile Web Development with Rails 7: (page 70) I am running windows 11 pro with rails 7.0.3 and ruby 3.1.2p20 (2022-04-12 revision...
#question/book-agile-web-development-with-rails-7
0 1129 1
New

Other popular topics Top

Rainer
Community>Journals

Programming Erlang Book Club
My first contact with Erlang was about 2 years ago when I used RabbitMQ, which is written in Erlang, for my job. This made me curious and...
/erlang/book-programming-erlang-2nd-edition#book-club
195 6815 95
New
Margaret
General Dev>Dev Chat

PragProg’s Medium Posts
Hello everyone! This thread is to tell you about what authors from The Pragmatic Bookshelf are writing on Medium.
#pragprog#blog-post
1147 29994 760
New
Maartz
General Dev>Dev Chat

Roc Language - a new purely functional programming language built for speed and ergonomics
Hi folks, I don’t know if I saw this here but, here’s a new programming language, called Roc Reminds me a bit of Elm and thus Haskell. ...
#programminguages#functional-programming
49 5164 14
New
Help
Game Dev>Questions

Can I use Java to program a game for Nintendo switch?
I am trying to crate a game for the Nintendo switch, I wanted to use Java as I am comfortable with that programming language. Can you use...
/java#nintendo
8 4771 3
New
PragmaticBookshelf
Community>In The Spotlight

Spotlight: Rebecca Skinner (Author) Interview and AMA!
Author Spotlight Rebecca Skinner @RebeccaSkinner Welcome to our latest author spotlight, where we sit down with Rebecca Skinner, auth...
#author-spotlight/haskell/book-effective-haskell
106 11719 28
New
AnfaengerAlex
Android>Questions

Unresolved Reference to android in build.gradle.kts – Beginner Issue
Hello, I’m a beginner in Android development and I’m facing an issue with my project setup. In my build.gradle.kts file, I have the foll...
#binding
0 7460 2
New
AstonJ
AI>In The News

DeepSeek (671B) running on a cluster of 8 Mac Mini Pros with 64GB RAM each
This is cool! DEEPSEEK-V3 ON M4 MAC: BLAZING FAST INFERENCE ON APPLE SILICON We just witnessed something incredible: the largest open-s...
#ai#macs/deepseek
0 6695 1
New
RobertRichards
Game Dev>Chat

Hair Salon Games for Girls Fun
Hair Salon Games for Girls Fun Girls Hair Saloon game is mainly developed for kids. This game allows users to select virtual avatars to ...
#ios#android#unity#fun
2 3556 1
New
PragmaticBookshelf
Backend>Learning Resources

Elixir Patterns
This book forgoes the abstract and instead provides concrete examples to help you better leverage the unique properties of Elixir, Erlang...
pragprog.com
#pragprog/elixir/erlang#published-book#beam/book-elixir-patterns
2 3476 2
New
PragmaticBookshelf
General Dev>Learning Resources

Write Better with Vale
Lint your docs like code: turn any style guide into enforceable rules with Vale and publish clear, consistent content every time. ...
pragprog.com
#pragprog#published-book#vale/book-write-better-with-vale
8 9973 5
New
Back to top

Latest in Effective Haskell

Effective Haskell Portal ❯

PragProg Customers

Pragmatic Bookshelf PragProg Customers ❯

Latest on Devtalk

Devtalk ❯

We ❤️ helpful members!

We reward our most helpful members via our MOTM scheme - by giving away a whopping 25 books per year!

Member of the Month

Devtalk Sponsors

Pragmatic Bookshelf

Practical resources that improve the lives of professional developers.

Erlang Solutions

We build trusted fault-tolerant systems that scale to billions of users.

Honeybadger

Real-time error tracking, performance insights, and observability for devs.

EEF

Supporting innovation across the BEAM ecosystem.

coders51

We build reliable cloud platforms for business-critical systems.

Manning Publications

Develop your skills with books, videos, and courses.

AppSignal

Catch errors, track performance, monitor hosts and more.

WyeWorks

Enabling companies to succeed by building software people love.

Pragmatic Studio

Courses that move you from confusion to "Aha, now I get it!"

Linux New Media

Publishing Linux Magazine, ADMIN, and MakerSpace for 25+ years.

View all our sponsors ❯

Categories:

Sub Categories:

Popular Portals

Devtalk Sponsors

Pragmatic Bookshelf

Practical resources that improve the lives of professional developers.

Erlang Solutions

We build trusted fault-tolerant systems that scale to billions of users.

Honeybadger

Real-time error tracking, performance insights, and observability for devs.

EEF

Supporting innovation across the BEAM ecosystem.

coders51

We build reliable cloud platforms for business-critical systems.

Manning Publications

Develop your skills with books, videos, and courses.

AppSignal

Catch errors, track performance, monitor hosts and more.

WyeWorks

Enabling companies to succeed by building software people love.

Pragmatic Studio

Courses that move you from confusion to "Aha, now I get it!"

Linux New Media

Publishing Linux Magazine, ADMIN, and MakerSpace for 25+ years.

View all our sponsors ❯

We're in Beta

About us Mission Statement See our Roadmap