hykw
How to set first-class module dynamically?
I have a logic like this. All the modules have the same patterns in their names(Foo.Module_[NUMERIC]). Can I set the module into f more simply like: f = Foo.Module_#{id}; f.get() ?
id = 2
f = case id do
"1" => Foo.Module_1
"2" => Foo.Module_2
"3" => Foo.Module_3
end
f.get()
defmodule Foo.Module_1 do
def get(), do: SOME-LOGICS-HERE
end
defmodule Foo.Module_2 do
def get(), do: SOME-LOGICS-HERE
end
defmodule Foo.Module_3 do
def get(), do: SOME-LOGICS-HERE
end
Most Liked
vidalraphael
That’s a somewhat unorthodox approach, but it’s possible:
# Will raise if there's an attempt to use a number
# that doesn't have a corresponding module
mod = String.to_existing_atom("Elixir.Foo.Module_#{num}")
# Just call afterwards
mod.get()
The use of the String.to_existing_atom/1 is necessary because string to atom conversion isn’t safe in Erlang/Elixir, as atoms are not garbage collected, and filling up the atoms table is one of the ways to bring down the BEAM. Since the modules should be defined in the first place, the atoms that reference their names will already exist.
Hope it helps you 
hykw
Popular in Discussions
Other popular topics
Latest on Elixir Forum
Sponsor Spotlight
Phoenix, LiveView, multimedia pipelines, distributed systems. 400 engineers, Elixir since 2017. Available for hire.
Categories:
Sub Categories:
Forums
Popular Tags
- #ecto
- #liveview
- #troubleshooting
- #learning-elixir
- #deployment
- #library
- #erlang
- #testing
- #genserver
- #mix
- #absinthe
- #remote-other
- #otp
- #plug
- #how-to-question
- #macros
- #postgres
- #channels
- #elixirconf
- #exunit
- #discussion
- #code-sync
- #javascript
- #podcasts
- #onsite
- #dialyzer
- #docker
- #authentication
- #umbrella
- #full-time-contract
- #podcasts-by-brainlid
- #ecto-query
- #elixir-ls
- #phoenix_html
- #iex
- #blog-post
- #graphql
- #genstage
- #ai
- #websockets
- #supervisor
- #advent-of-code
- #elixirconf-us
- #distillery
- #processes
- #forms
- #api
- #metaprogramming
- #security
- #hex
Our Sponsors
Build Elixir applications with speed and confidence.
Supporting innovation across the BEAM ecosystem.
We build reliable cloud platforms for business-critical systems.
Catch errors, track performance, monitor hosts and more.
Error tracking for Elixir devs who love to ship. Start your free account.
Develop your skills with books, videos, and courses.
Enabling companies to succeed by building software people love.
The deployment platform built for Elixir: PaaS ease, VPS control.
The team behind Membrane, Popcorn, LiveDebugger. Available for hire.
Courses that'll move you from confusion to "Aha, now I get it!"