How to handle nested case

[Gian Lorenzo Meocci]

Thanks a lot for the link!

On Sun, 19 Sept 2021 at 16:40, Paulo F. Oliveira <
paulo.ferraz.oliveira@REDACTED> wrote:

> 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 <glmeocci@REDACTED>
> 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 <attila.r.nohl@REDACTED>
>> 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 <glmeocci@REDACTED> 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
>>>
>>

-- 
GL
https://www.meocci.it <https://meox.github.io>
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