PragProg Customers

Effective Haskell: Example doesn’t work (page 8)

DW_Roth

DW_Roth

Effective Haskell: Example doesn’t work (page 8)

Title: Effective Haskell - Example doesn’t work (page 8)

Middle of page 8 says: "Create a new Main.hs and copy the example below to get started.

module Main where

makeGreeting salutation person =
salutation <> " " <> person

Now load up ghci and test out…"

If I load this file into ghci (or try to compile it), I get errors: "The IO action ‘main’ is not defined in the module ‘Main’.

The text shown is not complete as it doesn’t include a main module. The reader is left to figure out why it doesn’t work.

2 comments
#errata/book-effective-haskell
1 854 2

First Post!

RebeccaSkinner

RebeccaSkinner

Author of Effective Haskell

Thanks for pointing out that bug! It will be fixed as soon as the next beta update is released.
Until then, the correct example should be:

module Main where

makeGreeting salutation person =
  salutation <> " " <> person

main = print "no salutation to show yet"
Post #2

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
1 854 2
Last post

Popular Pragmatic Bookshelf topics Top

sdmoralesma
PragProg Customers

Web Development with Clojure, Third Edition: migrations/create not working: p159
Title: Web Development with Clojure, Third Edition - migrations/create not working: p159 When I execute the command: user=&gt; (create-...
#question/book-web-development-with-clojure-third-edition
5 1084 2
New
jeremyhuiskamp
PragProg Customers

Web Development with Clojure, Third Edition (vB17.0): create table syntax invalid
Title: Web Development with Clojure, Third Edition, vB17.0 (p9) The create table guestbook syntax suggested doesn’t seem to be accepted ...
#errata/book-web-development-with-clojure-third-edition
0 1835 1
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
adamwoolhether
PragProg Customers

Powerful Command-Line Applications in Go: Exercise Solutions (many pages)
Is there any place where we can discuss the solutions to some of the exercises? I can figure most of them out, but am having trouble with...
#question/book-powerful-command-line-applications-in-go
17 1396 9
New
jonmac
PragProg Customers

Kotlin and Android Development featuring Jetpack: allprojects should be moved to settings.gradle (page 245)
The allprojects block listed on page 245 produces the following error when syncing gradle: “org.gradle.api.GradleScriptException: A prob...
#suggestion/book-kotlin-and-android-development-featuring-jetpack
1 2304 1
New
jwandekoken
PragProg Customers

Programming Phoenix LiveView: Live Upload Match Error
Book: Programming Phoenix LiveView, page 142 (157/378), file lib/pento_web/live/product_live/form_component.ex, in the function below: d...
#errata/book-programming-phoenix-liveview
7 1158 10
New
a.zampa
PragProg Customers

Kotlin and Android Development featuring Jetpack: error concerning function getCurrentStandings in BaseballDao.java
@mfazio23 I’m following the indications of the book and arriver ad chapter 10, but the app cannot be compiled due to an error in the Bas...
#question/book-kotlin-and-android-development-featuring-jetpack
1 3397 6
New
NaplesDave
PragProg Customers

PragProg Customers Kotlin and Android Development: pg. 8 Build Gradle error: Could not get unknown property 'kotlin_version'
I am using Android Studio Chipmunk | 2021.2.1 Patch 2 Build #AI-212.5712.43.2112.8815526, built on July 10, 2022 Runtime version: 11.0....
#question/book-kotlin-and-android-development-featuring-jetpack
0 1456 2
New
mcpierce
PragProg Customers

Kotlin and Android Development featuring Jetpack: Unique constraint error when running chapter 5 code changes
@mfazio23 I’ve applied the changes from Chapter 5 of the book and everything builds correctly and runs. But, when I try to start a game,...
/book-kotlin-and-android-development-featuring-jetpack
0 1180 10
New

Other popular topics Top

PragmaticBookshelf
General Dev>Learning Resources

A Common-Sense Guide to Data Structures and Algorithms, Second Edition
Algorithms and data structures are much more than abstract concepts. Mastering them enables you to write code that runs faster and more e...
pragprog.com
#pragprog/python/ruby#published-book/book-a-common-sense-guide-to-data-structures-and-algorithms-second-edition#math#algorithms/js
19 6022 5
New
PragmaticBookshelf
General Dev>Learning Resources

Seven More Languages in Seven Weeks
Learn from the award-winning programming series that inspired the Elixir language, and go on a step-by-step journey through the most impo...
pragprog.com
#pragprog/elixir/julia/lua#published-book#factor/elm#minikanren/idris/book-seven-more-languages-in-seven-weeks
4 5862 0
New
AstonJ
General Dev>Hardware

GMK Serika Keycaps - Serika 2 available to order now!
I have seen the keycaps I want - they are due for a group-buy this week but won’t be delivered until October next year!!! :rofl: The Ser...
/keyboards#keycaps#mechanical-keyboards
9 5097 7
New
rustkas
Backend>Chat

Using Regular Expressions in Erlang
Intensively researching Erlang books and additional resources on it, I have found that the topic of using Regular Expressions is either c...
/erlang#regular-expressions
91 5662 43
New
foxtrottwist
General Dev>Dev Chat

Warp—The blazingly fast, Rust-based terminal
A few weeks ago I started using Warp a terminal written in rust. Though in it’s current state of development there are a few caveats (tab...
/rust#terminal
52 6785 22
New
PragmaticBookshelf
Community>In The Spotlight

Spotlight: Erin Dees (Author) Interview and AMA!
Author Spotlight Erin Dees @undees Welcome to our new author spotlight! We had the pleasure of chatting with Erin Dees, co-author of ...
#author-spotlight/ruby/rails/book-effective-testing-with-rspec-3/book-seven-more-languages-in-seven-weeks/book-cucumber-recipes#rspec
24 4247 11
New
PragmaticBookshelf
Community>In The Spotlight

Spotlight: VM Brasseur (Author) Interview and AMA!
Author Spotlight: VM Brasseur @vmbrasseur We have a treat for you today! We turn the spotlight onto Open Source as we sit down with V...
#author-spotlight/book-forge-your-future-with-open-source
16 5051 11
New
PragmaticBookshelf
Community>In The Spotlight

Spotlight: Bruce Tate (Author) Interview and AMA!
Author Spotlight: Bruce Tate @redrapids Programming languages always emerge out of need, and if that’s not always true, they’re defin...
/elixir/ruby/phoenix/book-seven-more-languages-in-seven-weeks/book-seven-languages-in-seven-weeks#liveview/book-programming-phoenix-liveview
54 5678 23
New
AstonJ
AI>Chat

How to: Run DeepSeek on Mac, Windows, and Linux!
This is a very quick guide, you just need to: Download LM Studio: https://lmstudio.ai/ Click on search Type DeepSeek, then select the o...
#macs/deepseek#guides#lm-studio
14 9328 10
New
PragmaticBookshelf
Backend>Learning Resources

Simplicity
Fight complexity and reclaim the original spirit of agility by learning to simplify how you develop software. The result: a more humane a...
pragprog.com
#pragprog#published-book/book-simplicity
10 6553 8
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