pichi

pichi

How can I define the recursive anonymous function in Elixir? In Erlang, I can write:

1> F = fun X([]) -> []; X([H|T]) -> [H+1|X(T)] end.
#Fun<erl_eval.20.79398840>
2> F([5,41,13]).
[6,42,14]

I can’t find in documentation a way how to write a similar function in Elixir.

Showing Posts 1 to 7

LostKobrakai

LostKobrakai

Afaik this is not supported in elixir.

pichi

pichi OP

So we are stick with this half Y-combinator solution? What a shame

iex(9)> f = fn l -> g = fn [], _ -> []; [h|t], f -> [h+1|f.(t,f)] end; g.(l,g) end
#Function<44.79398840/1 in :erl_eval.expr/5>
iex(10)> f.([3,41,5])                                                              
[4, 42, 6]

It’s like going ten years backwards when we have to do this in Erlang.

John-Goff

John-Goff

In elixir, unlike in Erlang, you can define modules in the shell. So when you do need to write a recursive function you can do

iex> defmodule Rec do
...>   def recurse([]), do: []
...>   def recurse([h | t]), do: [h + 1 | recurse(t)] 
...> end
pichi

pichi OP

Yes, you solved this trivial example but what if I would like to make function which returns recursive anonymous function with nontrivial closure. For example returning ad hoc enumerate protocol implementation.

John-Goff

John-Goff

I’m not sure I follow honestly. Could you give a more realistic example of what you’re trying to do if the above was too trivial?

Logan

Logan

f = fn
  ([], _fun) ->
    []
  ([h | t], fun) ->
    [h+1 | fun.(t, fun)]
  end

f.([1, 2, 3], f)
dom

dom

— All posts loaded —

Where Next? Top

Trending in Questions Top

stjefim
Hello! Suppose you are building workflow (order / task / payment) processing system with the following requirements: Each workflow con...
New
itzmidinesh
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
pragdave
How do I tell Hologram not to escape HTML when substituting into templates? {Textile.render(@product.long_description)} escapes the HTM...
New
rlipscombe
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
leoschweizer
Hi, we run different LLM models across a cluster, with each node loading a configurable subset. Model-specific queues let nodes consume ...
New
rlipscombe
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
adr
Hello all. I have a question as to best practices for code organization when implementing a liveview with a lot of responsibilities. Sup...
New

Other Trending Topics Top

dominicletz
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
raa-ziq
Hi everyone :waving_hand: I wanted to share something I’ve been building — NowBlind, a random chat app designed to help people discover ...
New
mudasobwa
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
KristerV
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
OndrejValenta
(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
kip
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

We're in Beta

About us Mission Statement

Options

Thread Display Mode




Thread Preview

Skip Thread Previews