Aetherus
I want to mimic ES6’s destructing assignment using Elixir’s sigil.
What I want to achieve is
~m{foo bar} = %{foo: 1, bar: 2}
foo #=> 1
bar #=> 2
So far I have the following code
defmodule DestructingAssignment do
defmacro __using__(_) do
quote do: import unquote(__MODULE__)
end
defmacro sigil_m({:<<>>, _line, [string]}, []) do
spec = string
|> String.split
|> Stream.map(&String.to_atom/1)
|> Enum.map(&{&1, {&1, [], Elixir}}) #=> [foo: {:foo, [], Elixir}, bar: {:bar, [], Elixir}]
{:%{}, [], spec}
end
end
When I run ~m{foo bar} = %{foo: 1, bar: 2}, pattern matching succeeds. But when I try to read the variable foo, it gives me
warning: variable "foo" does not exist and is being expanded to "foo()", please use parentheses to remove the ambiguity or change the variable name
iex:9
** (CompileError) iex:9: undefined function foo/0
I guess this is due to the macro hygiene, but as you can see, the sigil implementation doesn’t use quote. How can I inject local variable to the macro’s caller’s scope?
Trending in Questions
I’m aware of 2 such projects, are there others?
git: GitHub - team-alembic/realworld: A fullstack Phoenix LiveView application with back...
New
I having some trouble figuring out if I have set myself too strict of standards for my production server. Currently I can handle 75% of r...
New
Hi everyone.
My team and I have been working on a fairly modest app based around video streaming and chat, but we’ve landed a customer t...
New
I really like the adapter patterns that ecto, nebulex, waffle, etc. use and would love find something similar for a key management servic...
New
Hello folks!
So at work, we are seeing some situations where we have to define some “fixed” strings that are used across the codebase in...
New
How Can I Optimise Compile Time Dependencies
I have been building an elixir application for about 2 years now. Many modules and files ha...
New
Other Trending Topics
A little off-topic, but I feel like people here have a good head on their shoulders.
I used to be quite good at making software. Was luc...
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 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
Beam Bots (or just BB for short) is a framework for building fault-tolerant robotics applications in Elixir using familiar OTP patterns. ...
New
There has been a thread to discuss the Stack Overflow Developer Survey on this forum every year since 2018, so here’s yet another one for...
New
I love Elixir. It’s one of 2 programming languages I’ve ever fallen in love with.
But I don’t use it anymore.
Serverless was the promis...
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
- #discussion
- #code-sync
- #podcasts
- #javascript
- #onsite
- #dialyzer
- #docker
- #authentication
- #ai
- #umbrella
- #full-time-contract
- #podcasts-by-brainlid
- #ecto-query
- #blog-post
- #elixirconf-us
- #elixir-ls
- #phoenix_html
- #iex
- #graphql
- #genstage
- #websockets
- #supervisor
- #advent-of-code
- #distillery
- #processes
- #elixirconf-eu
- #api
- #forms
- #security
- #metaprogramming










Showing Posts 1 to 6- Show Best Posts
- Show All (oldest first)
- Show All (newest first)
kip
I think just one small change is required:
Aetherus
Works like a charm! But here come a new question, what does the last part of an AST node mean?
matteosister
Have a look at this: GitHub - whatyouhide/short_maps: ⚠️Retired⚠️ library that provided a ~m sigil for ES6-like map destructuring in Elixir. · GitHub
taiansu
According to Saša Jurić’s article about macros, the third part of variable AST represents where the quoting happens. If it’s
nil, the identifier is not hygienic. Check out paragraph “Discovering the AST structure” of the article and the series for the detail.KristerV
I have no ideas how macros work, but this is very useful and I made a string version also:
Works great! (so far)
KristerV
can’t edit.
this algo has served me well, but today i’d go for shorter_maps.