[erlang-questions] erlang sucks

[Mats Cronqvist]

Sean Hinde wrote:
>
> On 11 Mar 2008, at 19:26, Mats Cronqvist wrote:
>
>> Sean Hinde wrote:
>>>
>>> On 11 Mar 2008, at 12:47, Mats Cronqvist wrote:
>>>
>>>>
>>>> * 'if' is  completely worthless, and should ideally be obsoleted.
>>>
>>> No, no no! I like 'if' It allows some neat constructs that are 
>>> horrible with case.
>>
>> i was afraid no one was going to bite... still, I'd like an example 
>> or 2.
>
> I'm thinking of things like:
>
> case X of
>     _ when X == abc; X == xyz ->
>         do_abc_or_xyz();
>         _ when X == '123', X == '456' ->
>         do_123456()
>     '123' ->
>         do_123_only();
>         fred ->
>                 do_fred()
> end
>
> vs
>
> if
>     X == abc;
>     X == xyz ->
>         do_abc_or_xyz();
>         X == '123',
>     X == '456' ->
>         do_123456();
>     X == '123' ->
>         do_123_only();
>         X == fred ->
>                 do_fred()
> end
>
> I don't much like the _ when business.

  of course, a less (more?) contrived example would be this;

  case is_imaginary(Friend) of
    true -> sad(self());
    false-> sound(self())
  end.

 vs.

 FriendIsImaginary = is_imaginary(Friend),
 if
   not FriendIsImaginary -> sad(self());
   true -> sound(self())
 end.

  where the second one makes my head spin. the point is that you can't 
ignore the fact that you have to bind X, Y and Z in the 'if' example.

> 'if' is also useful when you want to branch on a bunch of unrelated 
> boolean variables in various combinations:
>
> case {X,Y,Z} of
>     {true, false, _} ->
>         do_a();
>         {false, _, true} ->
>         do_b();
>     _ ->
>         do_c()
> end
>
> vs
>
> if
>     X and not Y ->
>             do_a;
>     not X and Z ->
>             do_b;
>     true ->
>             do_c
>     end. 
  same here; when you take into account that you have to bind X, Y and Z 
in the second example, but not in the first, the 'case' version comes 
out ahead. objectively :>

  i remain convinced that 'if' is worthless and does nothing but add to 
the bloat.

  mats
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