
dsincl12
Real-World Event Sourcing: Incorrect definition of input and output (page 27)
On page 27 it says the following which is misleading:
“In pure functional programming terms, input and output are considered impure, because they are side effects.”
This is not correct, input and output are themselves not impure only the side effects. So this is a bit misleading. A pure function have input and output but with no side effects.
First Post!

autodidaddict
Author of Real-World Event Sourcing with Elixir
Thanks for pointing this out. I’ve clarified the input and output here as interactions with external systems, and not input to functions as parameters.
Popular Pragmatic Bookshelf topics

page 37
ANTLRInputStream input = new ANTLRInputStream(is);
as of ANTLR 4 .8 should be:
CharStream stream = CharStreams.fromStream(i...
New

Running the examples in chapter 5 c under pytest 5.4.1 causes an AttributeError: ‘module’ object has no attribute ‘config’.
In particula...
New

Many tasks_proj/tests directories exist in chapters 2, 3, 5 that have tests that use the custom markers smoke and get, which are not decl...
New

Title: Design and Build Great Web APIs - typo “https://company-atk.herokuapp.com/2258ie4t68jv” (page 19, third bullet in URL list)
Typo:...
New

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

Page 28: It implements io.ReaderAt on the store type.
Sorry if it’s a dumb question but was the io.ReaderAt supposed to be io.ReadAt?
...
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

Hi, I’ve got a question about the implementation of PubSub when using a Phoenix.Socket.Transport behaviour rather than channels.
Before ...
New

When running the program in chapter 8, “Implementing Combat”, the printout Health before attack was never printed so I assumed something ...
New

Docker-Machine became part of the Docker Toolbox, which was deprecated in 2020, long after Docker Desktop supported Docker Engine nativel...
New
Other popular topics
New

poll
poll
Be sure to check out @Dusty’s article posted here: An Introduction to Alternative Keyboard Layouts It’s one of the best write-...
New

Just done a fresh install of macOS Big Sur and on installing Erlang I am getting:
asdf install erlang 23.1.2
Configure failed.
checking ...
New

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

This looks like a stunning keycap set :orange_heart:
A LEGENDARY KEYBOARD LIVES ON
When you bought an Apple Macintosh computer in the e...
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

Not sure if following fits exactly this thread, or if we should have a hobby thread…
For many years I’m designing and building model air...
New

Oh just spent so much time on this to discover now that RancherOS is in end of life but Rancher is refusing to mark the Github repo as su...
New

If you are experiencing Rails console using 100% CPU on your dev machine, then updating your development and test gems might fix the issu...
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
Categories:
Sub Categories:
Popular Portals
- /elixir
- /rust
- /ruby
- /wasm
- /erlang
- /phoenix
- /keyboards
- /rails
- /js
- /python
- /security
- /go
- /swift
- /vim
- /clojure
- /emacs
- /haskell
- /java
- /onivim
- /svelte
- /typescript
- /crystal
- /kotlin
- /c-plus-plus
- /tailwind
- /gleam
- /ocaml
- /react
- /flutter
- /elm
- /vscode
- /ash
- /opensuse
- /centos
- /php
- /deepseek
- /html
- /zig
- /scala
- /sublime-text
- /textmate
- /lisp
- /debian
- /nixos
- /agda
- /react-native
- /kubuntu
- /arch-linux
- /django
- /revery
- /ubuntu
- /manjaro
- /spring
- /nodejs
- /diversity
- /lua
- /julia
- /slackware
- /c
- /markdown