How to handle nested case

[Gian Lorenzo Meocci]

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
>
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