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.
First Post!
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"
Popular Pragmatic Bookshelf topics
Hi everyone!
There is an error on the page 71 in the book “Programming machine learning from coding to depp learning” P. Perrotta. You c...
New
Title: Intuitive Python: docker run… denied error (page 2)
Attempted to run the docker command in both CLI and Powershell
PS C:\Users\r...
New
In case this helps anyone, I’ve had issues setting up the rails source code. Here were the solutions:
In Gemfile, change
gem 'rails'
t...
New
Dear Sophie.
I tried to do the “Authorization” exercise and have two questions:
When trying to plug in an email-service, I found the ...
New
#book-python-testing-with-pytest-second-edition
Hi. Thanks for writing the book. I am just learning so this might just of been an issue ...
New
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...
New
I think I might have found a problem involving SwitchCompat, thumbTint, and trackTint.
As entered, the SwitchCompat changes color to hol...
New
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...
New
Hi,
I completed chapter 6 but am getting the following error when running:
thread 'main' panicked at 'Failed to load texture: IoError(O...
New
Hello faithful readers! If you have tried to follow along in the book, you are asked to start up the dev environment via dx/build and ar...
New
Other popular topics
Free and open source software is the default choice for the technologies that run our world, and it’s built and maintained by people like...
New
Design and develop sophisticated 2D games that are as much fun to make as they are to play. From particle effects and pathfinding to soci...
New
SpaceVim seems to be gaining in features and popularity and I just wondered how it compares with SpaceMacs in 2020 - anyone have any thou...
New
New
New
Just done a fresh install of macOS Big Sur and on installing Erlang I am getting:
asdf install erlang 23.1.2
Configure failed.
checking ...
New
This looks like a stunning keycap set :orange_heart:
A LEGENDARY KEYBOARD LIVES ON
When you bought an Apple Macintosh computer in the e...
New
Tailwind CSS is an exciting new CSS framework that allows you to design your site by composing simple utility classes to create complex e...
New
zig/http.zig at 7cf2cbb33ef34c1d211135f56d30fe23b6cacd42 · ziglang/zig.
General-purpose programming language and toolchain for maintaini...
New
This is cool!
DEEPSEEK-V3 ON M4 MAC: BLAZING FAST INFERENCE ON APPLE SILICON
We just witnessed something incredible: the largest open-s...
New
Categories:
Sub Categories:
Popular Portals
- /elixir
- /rust
- /wasm
- /ruby
- /erlang
- /phoenix
- /keyboards
- /python
- /js
- /rails
- /security
- /go
- /swift
- /vim
- /clojure
- /emacs
- /haskell
- /java
- /svelte
- /onivim
- /typescript
- /kotlin
- /crystal
- /c-plus-plus
- /tailwind
- /react
- /gleam
- /ocaml
- /elm
- /flutter
- /vscode
- /ash
- /html
- /opensuse
- /zig
- /centos
- /deepseek
- /php
- /scala
- /react-native
- /lisp
- /textmate
- /sublime-text
- /nixos
- /debian
- /agda
- /django
- /kubuntu
- /deno
- /arch-linux
- /nodejs
- /revery
- /ubuntu
- /spring
- /manjaro
- /lua
- /diversity
- /julia
- /markdown
- /slackware








