andre
Effective Haskell: Chapter 12 - missing some code on p.438 (B9 - PDF version)
Chapter 12 starts with the code for the File Archive builder from the bottom of p.438 to p.440.
If the intention was to provide the complete version built during Chapter 11, the definition of the Encode typeclass is missing.
We can find it on p.418-419, which is
class Encode a where
encode :: a -> ByteString
encode = BS.drop 4 .encodeWithSize
encodeWithSize :: a -> ByteString
encodeWithSize a =
let s = encode a
l = fromIntegral $ BS.length s
in word32ToByteString l <> s
{-# MINIMAL encode | encodeWithSize #-}
Popular Pragmatic Bookshelf topics
When I try the command to create a pair of migration files I get an error.
user=> (create-migration "guestbook")
Execution error (Ill...
New
I can’t setup the Rails source code. This happens in a working directory containing multiple (postgres) Rails apps.
With:
ruby-3.0.0
s...
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
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
When I run the coverage example to report on missing lines, I get:
pytest --cov=cards --report=term-missing ch7
ERROR: usage: pytest [op...
New
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
On page 78 the following code appears:
<%= link_to ‘Destroy’, product,
class: ‘hover:underline’,
method: :delete,
data: { confirm...
New
When running the program in chapter 8, “Implementing Combat”, the printout Health before attack was never printed so I assumed something ...
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
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
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
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
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
Programming Ruby is the most complete book on Ruby, covering both the language itself and the standard library as well as commonly used t...
New
Author Spotlight:
Peter Ullrich
@PJUllrich
Data is at the core of every business, but it is useless if nobody can access and analyze ...
New
Author Spotlight:
Bruce Tate
@redrapids
Programming languages always emerge out of need, and if that’s not always true, they’re defin...
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
Node.js v22.14.0 has been released.
Link: Release 2025-02-11, Version 22.14.0 'Jod' (LTS), @aduh95 · nodejs/node · GitHub
New
Fight complexity and reclaim the original spirit of agility by learning to simplify how you develop software. The result: a more humane a...
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
- /onivim
- /typescript
- /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
- /debian
- /nixos
- /agda
- /deno
- /django
- /kubuntu
- /arch-linux
- /nodejs
- /spring
- /ubuntu
- /revery
- /manjaro
- /julia
- /diversity
- /lua
- /markdown
- /slackware
Devtalk Sponsors
Practical resources that improve the lives of professional developers.
We build trusted fault-tolerant systems that scale to billions of users.
Real-time error tracking, performance insights, and observability for devs.
Supporting innovation across the BEAM ecosystem.
We build reliable cloud platforms for business-critical systems.
Develop your skills with books, videos, and courses.
Catch errors, track performance, monitor hosts and more.
Enabling companies to succeed by building software people love.
Courses that move you from confusion to "Aha, now I get it!"
Publishing Linux Magazine, ADMIN, and MakerSpace for 25+ years.