Re: How to handle nested case

Hi, Gian.

You might be interested in reading [1], first shown to the Erlang world in
[2] (there's more info. in the archives, if you search).

FYI, it is being hacked away, at this very moment, in SpawnFest 2021:
https://github.com/spawnfest/eep49ers.

Cheers.

- Paulo F. Oliveira

[1] https://github.com/erlang/eep/blob/master/eeps/eep-0049.md
[2] http://erlang.org/pipermail/eeps/2018-September/000554.html

On Sun, 19 Sept 2021 at 14:37, Gian Lorenzo Meocci <[email protected]>
wrote:

> I think that there isn't a generic solution for this problem. It’s time to
> introduce the 'with' operator in Erlang 😂
>
> Il Dom 19 Set 2021, 09:06 Attila Rajmund Nohl <[email protected]>
> ha scritto:
>
>> Hello!
>>
>> One way (I haven't actually tried to compile this, but hopefully you
>> get the idea):
>>
>> get_nas_from_conf() ->
>>   try
>>     {ok, Server} = get_radius_host(),
>>     {ok, Port} = get_radius_port(),
>>     {ok, Secret} = get_radius_secret(),
>>     {Server, Port, Secret};
>>   catch
>>     error:{badmatch, E} ->
>>       E
>> end.
>>
>> Of course, if the badmatch comes from the get_* functions, this
>> construct might catch that too, but you might be able to  ensure this
>> doesn't happen.
>>
>> Gian Lorenzo Meocci <[email protected]> ezt írta (időpont: 2021.
>> szept. 18., Szo, 22:50):
>> >
>> > Hi,
>> > I have a function like this:
>> >
>> > get_nas_from_conf() ->
>> > case get_radius_host() of
>> > {ok, Server} ->
>> > case get_radius_port() of
>> > {ok, Port} ->
>> > case get_radius_secret() of
>> > {ok, Secret} ->
>> > {Server, Port, Secret};
>> > E -> E
>> > end;
>> > E ->
>> > E
>> > end;
>> > E ->
>> > E
>> > end.
>> >
>> > Which is the best way to write this kind of function?
>> >
>> > I'd like to have a with operator like in Elixir, to rewrite my function
>> in this way:
>> >
>> > get_nas_from_conf() ->
>> > with {ok, Server} <- get_radius_host(),
>> > {ok, Port} = get_radius_port(),
>> > {ok, Secret} = get_radius_secret() ->
>> > {Server, Port, Secret};
>> > catch
>> > {error, _Reason} = E ->
>> > E
>> > end.
>> >
>> > Any suggestion?
>> >
>> > --
>> > GL
>> > https://www.meocci.it
>>
>