Fl4m3Ph03n1x
List of monad libaries for Elixir
Background
I use a library called rop in my code, which is basically an implementation of the Error/Result Monad.
On my never ending search for improvement, I have decided to adopt mix format in one of my personal projects.
Problem
The problem here is that mix format and the rop library don’t play nice together. The library defines as a macro the operator >>>, which is also the same operator used for bitwise operations in Elixir.
So the code does not get properly formatted. Ever.
I have tried to contact the maintainer of the project via the project page by creating issues, but to no avail. The project has also not been updated for several years now which leads to me to think its sunny days are long behind it.
Instead of cloning the project and doing a duplicate of someone else’s work (albeit with some changes and fixes) I have decided it would be preferable to look for another library.
What am I looking for?
I am looking for Monad libraries in Elixir that:
- work with
mix format(this means the pipeline operators must be one of elixir/lib/elixir/lib/code/formatter.ex at v1.11.4 · elixir-lang/elixir · GitHub) - have an error monad that allows me to pipe values like in Rop
- the project must not be archived
Thus I have found the following options:
Which is not a lot …
Question
Cloning the library in question to fix it is not totally out of question, however unless I add some serious heat to the project I see it more as polluting the hex archive with a duplicate of something that already exists.
- what would you do in my situation?
- what other monad / fp libraries do you know?
Most Liked
hauleth
Maybe change an idea a little and write your own macro like:
defmacro on_ok(value, call) do
quote do
case unquote(value) do
{:ok, val} -> {:ok, unquote(Macro.pipe(quote(do: val), call, 0))}
{:error, _} = error -> error
end
end
end
Now it is useable like:
foo()
|> on_ok(bar())
|> on_ok(baz())
Which will be logically equivalent to:
with {:ok, a} <- foo(),
{:ok, b} <- bar(a),
{:ok, c} <- baz(b),
do: {:ok, c}
kokolegorille
Maybe Witchcraft. You might also find videos from the author…
https://www.youtube.com/results?search_query=brooklyn+zelenka
But You might have the same formatting concerns.
| Family | Function | Operator |
|---|---|---|
| Setoid | equivalent? | == |
| nonequivalent? | != | |
| Ord | greater_than? | > |
| lesser_than? | < | |
| Semigroup | append | <> |
| Functor | lift | ~> |
| convey | ~>> | |
| chain | >>> | |
| over | <~ | |
| ap | <<~ | |
| reverse_chain | <<< | |
| Semigroupoid | compose | < |
| pipe_compose | <~> | |
| Arrow | product | ^^^ |
| fanout | &&& |
fuelen
The library is so small, that I’d rather copy that 1 macro to my codebase and replace >>> with ~>>
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