dsincl12

dsincl12

Real-World Event Sourcing: Incorrect definition of input and output (page 27)

@autodidaddict

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

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.

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
telemachus
Python Testing With Pytest - Chapter 2, warnings for “unregistered custom marks” While running the smoke tests in Chapter 2, I get these...
New
brianokken
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
brian-m-ops
#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
Charles
In general, the book isn’t yet updated for Phoenix version 1.6. On page 18 of the book, the authors indicate that an auto generated of ro...
New
brunogirin
When installing Cards as an editable package, I get the following error: ERROR: File “setup.py” not found. Directory cannot be installe...
New
taguniversalmachine
It seems the second code snippet is missing the code to set the current_user: current_user: Accounts.get_user_by_session_token(session["...
New
jonmac
The allprojects block listed on page 245 produces the following error when syncing gradle: “org.gradle.api.GradleScriptException: A prob...
New
kolossal
Hi, I need some help, I’m new to rust and was learning through your book. but I got stuck at the last stage of distribution. Whenever I t...
New
New

Other popular topics Top

wolf4earth
@AstonJ prompted me to open this topic after I mentioned in the lockdown thread how I started to do a lot more for my fitness. https://f...
New
Exadra37
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
DevotionGeo
I know that -t flag is used along with -i flag for getting an interactive shell. But I cannot digest what the man page for docker run com...
New
AstonJ
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
gagan7995
API 4 Path: /user/following/ Method: GET Description: Returns the list of all names of people whom the user follows Response [ { ...
New
rustkas
Intensively researching Erlang books and additional resources on it, I have found that the topic of using Regular Expressions is either c...
New
PragmaticBookshelf
Rails 7 completely redefines what it means to produce fantastic user experiences and provides a way to achieve all the benefits of single...
New
DevotionGeo
I have always used antique keyboards like Cherry MX 1800 or Cherry MX 8100 and almost always have modified the switches in some way, like...
New
AstonJ
If you’re getting errors like this: psql: error: connection to server on socket “/tmp/.s.PGSQL.5432” failed: No such file or directory ...
New
PragmaticBookshelf
Fight complexity and reclaim the original spirit of agility by learning to simplify how you develop software. The result: a more humane a...
New

Sub Categories: