MeEd

MeEd

Title: Effective Haskell (Page 31)

@RebeccaSkinner

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

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!

Where Next?

Popular Pragmatic Bookshelf topics Top

jeffmcompsci
Title: Design and Build Great Web APIs - typo “https://company-atk.herokuapp.com/2258ie4t68jv” (page 19, third bullet in URL list) Typo:...
New
simonpeter
When I try the command to create a pair of migration files I get an error. user=&gt; (create-migration "guestbook") Execution error (Ill...
New
AleksandrKudashkin
On the page xv there is an instruction to run bin/setup from the main folder. I downloaded the source code today (12/03/21) and can’t see...
New
joepstender
The generated iex result below should list products instead of product for the metadata. (page 67) iex&gt; product = %Product{} %Pento....
New
jeremyhuiskamp
Title: Web Development with Clojure, Third Edition, vB17.0 (p9) The create table guestbook syntax suggested doesn’t seem to be accepted ...
New
digitalbias
Title: Build a Weather Station with Elixir and Nerves: Problem connecting to Postgres with Grafana on (page 64) If you follow the defau...
New
oaklandgit
Hi, I completed chapter 6 but am getting the following error when running: thread 'main' panicked at 'Failed to load texture: IoError(O...
New
adamwoolhether
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...
New
ggerico
I got this error when executing the plot files on macOS Ventura 13.0.1 with Python 3.10.8 and matplotlib 3.6.1: programming_ML/code/03_...
New
dachristenson
I just bought this book to learn about Android development, and I’m already running into a major issue in Ch. 1, p. 20: “Update activity...
New

Other popular topics Top

DevotionGeo
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
PragmaticBookshelf
From finance to artificial intelligence, genetic algorithms are a powerful tool with a wide array of applications. But you don't need an ...
New
AstonJ
There’s a whole world of custom keycaps out there that I didn’t know existed! Check out all of our Keycaps threads here: https://forum....
New
New
AstonJ
I ended up cancelling my Moonlander order as I think it’s just going to be a bit too bulky for me. I think the Planck and the Preonic (o...
New
AstonJ
In case anyone else is wondering why Ruby 3 doesn’t show when you do asdf list-all ruby :man_facepalming: do this first: asdf plugin-upd...
New
AstonJ
We’ve talked about his book briefly here but it is quickly becoming obsolete - so he’s decided to create a series of 7 podcasts, the firs...
New
New
New
CommunityNews
A Brief Review of the Minisforum V3 AMD Tablet. Update: I have created an awesome-minisforum-v3 GitHub repository to list information fo...
New

Sub Categories: