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

jimschubert
In Chapter 3, the source for index introduces Config on page 31, followed by more code including tests; Config isn’t introduced until pag...
New
Alexandr
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
mikecargal
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
jeremyhuiskamp
Title: Web Development with Clojure, Third Edition, vB17.0 (p9) The create table guestbook syntax suggested doesn’t seem to be accepted ...
New
New
AndyDavis3416
@noelrappin Running the webpack dev server, I receive the following warning: ERROR in tsconfig.json TS18003: No inputs were found in c...
New
curtosis
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
brunogirin
When running tox for the first time, I got the following error: ERROR: InterpreterNotFound: python3.10 I realised that I was running ...
New
jonmac
The allprojects block listed on page 245 produces the following error when syncing gradle: “org.gradle.api.GradleScriptException: A prob...
New
rainforest
Hi, I’ve got a question about the implementation of PubSub when using a Phoenix.Socket.Transport behaviour rather than channels. Before ...
New

Other popular topics Top

AstonJ
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
PragmaticBookshelf
Brace yourself for a fun challenge: build a photorealistic 3D renderer from scratch! In just a couple of weeks, build a ray tracer that r...
New
AstonJ
Curious to know which languages and frameworks you’re all thinking about learning next :upside_down_face: Perhaps if there’s enough peop...
New
AstonJ
You might be thinking we should just ask who’s not using VSCode :joy: however there are some new additions in the space that might give V...
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
AstonJ
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
PragmaticBookshelf
Create efficient, elegant software tests in pytest, Python's most powerful testing framework. Brian Okken @brianokken Edited by Kat...
New
PragmaticBookshelf
Build efficient applications that exploit the unique benefits of a pure functional language, learning from an engineer who uses Haskell t...
New
hilfordjames
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
PragmaticBookshelf
Explore the power of Ash Framework by modeling and building the domain for a real-world web application. Rebecca Le @sevenseacat and ...
New

Sub Categories: