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
As per the title, thanks.
New
The following is cross-posted from the original Ray Tracer Challenge forum, from a post by garfieldnate. I’m cross-posting it so that the...
New
Title: Hands-On Rust (Chap 8 (Adding a Heads Up Display)
It looks like
.with_simple_console_no_bg(SCREEN_WIDTH*2, SCREEN_HEIGHT*2...
New
Hi Jamis,
I think there’s an issue with a test on chapter 6. I own the ebook, version P1.0 Feb. 2019.
This test doesn’t pass for me:
...
New
Hi Travis! Thank you for the cool book! :slight_smile:
I made a list of issues and thought I could post them chapter by chapter. I’m rev...
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
Hi,
I completed chapter 6 but am getting the following error when running:
thread 'main' panicked at 'Failed to load texture: IoError(O...
New
Hi all,
currently I wonder how the Tailwind colours work (or don’t work).
For example, in app/views/layouts/application.html.erb I have...
New
Book: Programming Phoenix LiveView, page 142 (157/378), file lib/pento_web/live/product_live/form_component.ex, in the function below:
d...
New
@mfazio23
Android Studio will not accept anything I do when trying to use the Transformations class, as described on pp. 140-141. Googl...
New
Other popular topics
A thread that every forum needs!
Simply post a link to a track on YouTube (or SoundCloud or Vimeo amongst others!) on a separate line an...
New
If it’s a mechanical keyboard, which switches do you have?
Would you recommend it? Why?
What will your next keyboard be?
Pics always w...
New
Machine learning can be intimidating, with its reliance on math and algorithms that most programmers don't encounter in their regular wor...
New
Write Elixir tests that you can be proud of. Dive into Elixir’s test philosophy and gain mastery over the terminology and concepts that u...
New
I know that these benchmarks might not be the exact picture of real-world scenario, but still I expect a Rust web framework performing a ...
New
Curious to know which languages and frameworks you’re all thinking about learning next :upside_down_face:
Perhaps if there’s enough peop...
New
Learn different ways of writing concurrent code in Elixir and increase your application's performance, without sacrificing scalability or...
New
There appears to have been an update that has changed the terminology for what has previously been known as the Taskbar Overflow - this h...
New
Will Swifties’ war on AI fakes spark a deepfake porn reckoning?
New
Jan | Rethink the Computer.
Jan turns your computer into an AI machine by running LLMs locally on your computer. It’s a privacy-focus, l...
New
Categories:
Sub Categories:
Popular Portals
- /elixir
- /rust
- /wasm
- /ruby
- /erlang
- /phoenix
- /keyboards
- /python
- /js
- /rails
- /security
- /go
- /swift
- /vim
- /clojure
- /java
- /emacs
- /haskell
- /svelte
- /typescript
- /onivim
- /kotlin
- /c-plus-plus
- /crystal
- /tailwind
- /react
- /gleam
- /ocaml
- /elm
- /flutter
- /vscode
- /ash
- /html
- /opensuse
- /zig
- /centos
- /deepseek
- /php
- /scala
- /react-native
- /lisp
- /sublime-text
- /textmate
- /nixos
- /debian
- /agda
- /deno
- /django
- /kubuntu
- /arch-linux
- /nodejs
- /spring
- /revery
- /ubuntu
- /manjaro
- /lua
- /diversity
- /julia
- /markdown
- /c









