[erlang-questions] I think I wish I could write case Any of whatever -> _ end.

[Ulf Wiger]

On 05/19/2010 05:30 AM, Richard O'Keefe wrote:
> 
> On May 19, 2010, at 3:11 PM, Eric Newhuis (personal) wrote:
> 
>> I appreciate all your comments.
>>
>> I still don't like temporary variables like X or whatever because they
>> contain no semantic quality and there is a tension between short names
>> to make the pattern obvious and longer names for reunderstanding.
> 
> The variable name X has been used in the examples,
> because the examples have been free of content.
> No-one, as far as I am aware, is arguing for the use of X
> _as such_, although it is at least better than _  or ~ .
> 
> This is why I keep on screaming for *real* examples.
> I predict that in real examples, we can find a way to express
> what we want with meaningful variable names.

Personally, I quite often use constructs like

open(F) ->
  case file:open(F, [read]) of
     {ok, Fd} -> Fd;
     {error,_} = Error ->
         erlang:error(Error)
  end.

Matching the error clause that way not only avoids constructing
a tuple needlessly, but also signals that I really don't care
/why/ it fails in this particular context - except when debugging,
which is why I report it. Raising an exception
highlights the fact that I /expect/ it to succeed.

Perhaps not the best of examples, but it was the one that came
to mind.

BR,
Ulf W
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