How can I get Elixir to help me with generating match specifications from funs. There is an Erlang function :ets.fun2ms/1 which can do this. Sort of anyway, in that the Erlang compiler actually tranforms this to the match specification at compile time. Can I tell the Elixir compiler to do this tran…

There is no way to have ets:fun2ms/1 in Elixir, as Elixir disallows parse transforms. However you can use macros to achieve the same thing .

There is this old post… [image] Ets.fun2ms needs ms_transform error Questions Hello everyone, I have some strange error message when using :ets.fun2ms. I am trying to filter an ets table based on some time. def get_obsolete_check_in(time) do fun = :ets.fu…

There is also @ityonemo ’s https://github.com/E-xyza/match_spec :ets matchspec helper library for elixir. Exposes the fun2ms/1 macro which transforms elixir-style function code into ets matchspecs. iex> require MatchSpec iex> MatchSpec.fun2ms(fn {key, value} when key === :foo -> value end) [{{:"…

Thanks for the suggestions. Why does the Elixir compiler disallow parse transforms? The problm is I have another issue than just doing it from Elixir :smiley: and that is I want to do it from LFE (Lisp Flavoured Erlang) as well. And there I have records which Elixir doesn’t, and these 2 packages, d…

Here is discussion https://github.com/elixir-lang/elixir/issues/5762 Writing such macro also shouldn’t be really hard there, so it can go that route.

Transforming funs to match specifications

Questions & Help Questions

kokolegorille January 6, 2023, 6:07pm 3

There is this old post…

Maybe this package can help?