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From: Paul Davis <paul.joseph.davis@gmail.com>
Date: Mon, 6 Dec 2010 10:22:17 -0500
Message-ID: <AANLkTi=3nRqY74sgyK-TSx4OpKw239xHEYxpPANDaDwF@mail.gmail.com>
Subject: Re: svn commit: r1042260 -
 /couchdb/trunk/src/couchdb/couch_native_process.erl
To: dev@couchdb.apache.org
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On Mon, Dec 6, 2010 at 10:19 AM, Adam Kocoloski <kocolosk@apache.org> wrote=
:
> On Dec 5, 2010, at 5:34 AM, Paul Davis wrote:
>
>> On Sun, Dec 5, 2010 at 3:19 AM, Jason Smith <jhs@couchone.com> wrote:
>>> On Sun, Dec 5, 2010 at 6:06 AM, =A0<jan@apache.org> wrote:
>>>> + =A0 =A0 =A0 =A0case catch Fun(Doc, Req) of
>>>> + =A0 =A0 =A0 =A0true -> true;
>>>> + =A0 =A0 =A0 =A0false -> false;
>>>> + =A0 =A0 =A0 =A0{'EXIT', Error} -> ?LOG_ERROR("~p", [Error])
>>>> + =A0 =A0 =A0 =A0end
>>>
>>> The O'Reilly book _Erlang Programming_ suggests that catch expressions
>>> (the older form before try...catch came out) are not as elegant as
>>> try...catch.
>>>
>>> http://books.google.com/books?id=3DQr_WuvfTSpEC&pg=3DPA74&lpg=3DPA74&so=
urce=3Dbl&ots=3DaK-DfyxREb&sig=3DLA1Fi-lSKEPJNvMFdp0kXzOxDg8&hl=3Den&ei=3DW=
0T7TJLpMY_QrQffr4HBCA&sa=3DX&oi=3Dbook_result&ct=3Dresult&resnum=3D1&ved=3D=
0CBIQ6AEwAA#v=3Donepage&q&f=3Dfalse
>>>
>>> Also Joe Armstrong's book states that you lose a lot of precision
>>> analyzing the cause of an error.
>>>
>>> FYI.
>>>
>>> --
>>> Jason Smith
>>> CouchOne Hosting
>>>
>>
>> I'm not sure about the book's definition of elegant, but:
>>
>> case (catch Fun()) of
>> =A0 Val1 -> foo;
>> =A0 Val2 -> bar;
>> =A0 {Error, Reason} -> other
>> end
>>
>> Seems more readable than:
>>
>> try
>> =A0 =A0case Fun() of
>> =A0 =A0 =A0 =A0Val1 -> foo;
>> =A0 =A0 =A0 =A0Val2 -> bar
>> =A0 =A0end
>> catch
>> =A0 =A0throw:{Error, Reason} -> other
>> end
>>
>> Its true that you end up collapsing the Error and Response domains
>> into a single namespace, but in general, most things don't look like
>> errors.
>
> It can be made simpler:
>
> try Fun() of
> =A0 =A0Val1 -> foo;
> =A0 =A0Val2 -> bar
> catch
> =A0 =A0{Error, Reason} -> other
> end
>
>

That's not bad. I've never seen "try F() of" before. Is it new or am I blin=
d?