oliveiragahenrique
I’m designing a pure functional data structure to manage banking accounts, a simplified version of it would be:
defmodule Account do
defstruct balance: 0, limit: -500
def new() do
%Account{}
end
def deposit(%Account{} = account, amount) do
new_account =
%Account{account | balance: account.balance + amount}
{:ok, new_account}
end
def withdraw(%Account{} = account, amount) do
new_balance = account.balance - amount
if new_balance >= account.limit do
new_account =
%Account{account | balance: new_balance}
{:ok, new_account}
else
{:denied, "No funds", account}
end
end
end
My question is about when should I use the response pattern of {:ok, data} for sucess and {:error, reason, unchanged_data} for failures.
This sounds like the way to go here on this problem, but if I go with this pattern I lose the feature of do something like this:
account =
Account.new()
|> Account.deposit(%{amount: 5000})
|> Account.deposit(%{amount: 3000})
|> Account.withdraw(%{amount: 1000})
I really like to design modules that could use the pipe operator like this, but how to do this when the module functions can fail?
If I just remove the :ok from the sucess response would solve the problem, but is this a good pattern?
What you guys think? How can I keep the pipe feature together with a good response check validation?
Trending in Questions
Hi all,
I’m working on a Phoenix project where I need to make external HTTP requests and I’m trying to choose between Req and HTTPoison....
New
I’m very new to Elixir, so sorry if this is a silly question:
I am wondering what happens to the mailbox of a process when the machine i...
New
How do I tell Hologram not to escape HTML when substituting into templates?
{Textile.render(@product.long_description)}
escapes the HTM...
New
Background
When trying to execute mix release on a Windows 11 machine for a Phoenix project I get the following error:
* assembling mark...
New
I’d like to create a file with 600 permissions (rw-------), but there’s a race condition if I create it and then change the permissions. ...
New
Is there a way to import record definitions in the iex shell for pretty printing (similar to the rr command in the erl shell)? This woul...
New
When I use Mix.install with a git dependency, using git@github.com:... how do I change the SSH identity used?
I’ve got two Github accoun...
New
Other Trending Topics
Hey there,
I haven’t seen a list of useful Elixir specific skills for the popular AI tools yet so I’m starting one here with my first.
...
New
Hi everyone :waving_hand:
I wanted to share something I’ve been building — NowBlind, a random chat app designed to help people discover ...
New
I fully migrated to my own harness from Anthropic/Gemini and I think it’s time to share it. Welcome DSH, the DeepSeek Harness, fully writ...
New
Hey. Is there anyone here who creates agents in their apps? Not talking about using agents, but creating them. I’m finding it pretty diff...
New
(I just needed to vent somewhere and LinkedIn is full of hope, or hype, I’m not sure which exactly)
AI dream has many faces, but general...
New
Localize is the next generation localisation library for Elixir. Think of it as ex_cldr version 3.0. The first version will be released ...
New
Categories:
Sub Categories:
Forums
Popular Tags
- #ecto
- #liveview
- #troubleshooting
- #learning-elixir
- #library
- #deployment
- #erlang
- #testing
- #genserver
- #mix
- #absinthe
- #remote-other
- #otp
- #plug
- #how-to-question
- #macros
- #postgres
- #elixirconf
- #channels
- #exunit
- #code-sync
- #discussion
- #podcasts
- #javascript
- #onsite
- #dialyzer
- #docker
- #authentication
- #ai
- #umbrella
- #elixirconf-us
- #full-time-contract
- #podcasts-by-brainlid
- #blog-post
- #ecto-query
- #elixir-ls
- #phoenix_html
- #iex
- #graphql
- #genstage
- #websockets
- #supervisor
- #advent-of-code
- #distillery
- #elixirconf-eu
- #processes
- #security
- #api
- #forms
- #performance










Showing Posts 1 to 3- Show Best Posts
- Show All (oldest first)
- Show All (newest first)
kokolegorille
If the pipeline can break, I would use with…
bottlenecked
@rrrene has written a series of articles on data flow patterns that perhaps could help. You may want to read up on the Token-based approach for your specific use case.
oliveiragahenrique
Great tip! Gonna check it out later for sure!