MeEd
Title: Effective Haskell (Page 31)
At the bottom of page 31 when let is added to the example greeting I cannot get the example to work. I’ve tried rechecking spacing inside the example, made sure I copied the example correctly and put in hours trying to get the example to work. I get different errors every time I try to run it in ghci.
First Post!
RebeccaSkinner
Author of Effective Haskell
Hey, sorry you’re having a problem! Here’s a working version of the example you can copy and paste:
module Main where
makeGreeting salutation person =
let messageWithTrailingSpace = salutation <> " "
in messageWithTrailingSpace <> person
extendedGreeting person =
let hello = makeGreeting "Hello" person
goodDay = makeGreeting "I hope you have a nice afternoon" person
goodBye = makeGreeting "see you later" person
in hello <> "\n" <> goodDay <> "\n" <> goodBye
main = print $ extendedGreeting "George"
If you can paste your code and the output of the errors I’d be happy to help you spot what’s going on!
Popular Pragmatic Bookshelf topics
I thought that there might be interest in using the book with Rails 6.1 and Ruby 2.7.2. I’ll note what I needed to do differently here.
...
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
The book has the same “Problem space/Solution space” diagram on page 18 as is on page 17. The correct Problem/Solution space diagrams ar...
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
“The ProductLive.Index template calls a helper function, live_component/3, that in turn calls on the modal component. ”
Excerpt From: Br...
New
I found an issue in Chapter 7 regarding android:backgroundTint vs app:backgroundTint.
How to replicate:
load chapter-7 from zipfile i...
New
Title: Build a Weather Station with Elixir and Nerves: Problem connecting to Postgres with Grafana on (page 64)
If you follow the defau...
New
When running tox for the first time, I got the following error:
ERROR: InterpreterNotFound: python3.10
I realised that I was running ...
New
AWDWR 7, page 152, page 153:
Hello everyone,
I’m a little bit lost on the hotwire part. I didn’t fully understand it.
On page 152 @rub...
New
I’ve got to the end of Ch. 11, and the app runs, with all tabs displaying what they should – at first. After switching around between St...
New
Other popular topics
I am thinking in building or buy a desktop computer for programing, both professionally and on my free time, and my choice of OS is Linux...
New
Please tell us what is your preferred monitor setup for programming(not gaming) and why you have chosen it.
Does your monitor have eye p...
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
Do the test and post your score :nerd_face:
:keyboard:
If possible, please add info such as the keyboard you’re using, the layout (Qw...
New
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. ...
New
Was just curious to see if any were around, found this one:
I got 51/100:
Not sure if it was meant to buy I am sure at times the b...
New
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...
New
Author Spotlight
Erin Dees
@undees
Welcome to our new author spotlight! We had the pleasure of chatting with Erin Dees, co-author of ...
New
Node.js v22.14.0 has been released.
Link: Release 2025-02-11, Version 22.14.0 'Jod' (LTS), @aduh95 · nodejs/node · GitHub
New
Use advanced functional programming principles, practical Domain-Driven Design techniques, and production-ready Elixir code to build scal...
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
- /flutter
- /elm
- /vscode
- /ash
- /html
- /opensuse
- /zig
- /centos
- /deepseek
- /php
- /scala
- /react-native
- /lisp
- /textmate
- /sublime-text
- /nixos
- /debian
- /agda
- /deno
- /django
- /kubuntu
- /arch-linux
- /nodejs
- /spring
- /revery
- /ubuntu
- /manjaro
- /lua
- /diversity
- /julia
- /markdown
- /v









