[eeps] Request for comments on EEP-25 "Unnesting cases"

Dave Smith <>
Sat Dec 20 01:48:49 CET 2008


Of course, I meant "peers" and not "piers"

2008/12/19 Dave Smith <>

> I'd favour omitting the "or" and I would tend to format it like this...
>
> case Expr of
>     Pat -> Expr ;
> case Expr of
>     Pat -> Expr ;
>     Pat -> Expr
> end.
>
> After all the case's are piers and belong at the same indent level. If we
> do go with an "or", isn't the ";" redundant?  Semantically, I've always
> considered ";" to mean "or" and "," to mean "and" in Erlang.
>
> I can appreciate Richard's "unique" formatting style. Unfortunately,
> optional preceding ";" is not allowed on the first  pattern.
>
> case Expr of
>    ; Pat -> Expr
> or case Expr of
>    ; Pat -> Expr
>    ; Pat -> Expr end.
>
>
> 2008/12/19 Robert Virding <>
>
>> 2008/12/19 Ulf Wiger <>
>>
>>> 2008/12/19 Raimo Niskanen <<raimo%>
>>> >:
>>> > I would like you to submit comments regarding EEP-25 on the
>>> >  mailing list.
>>>
>>> I for one find it acceptable. The "; or case" construct is ok -
>>> perhaps not extremely elegant, but conveys the meaning
>>> very well.
>>>
>>
>> Note that "; or case" is Richard's O'Keefe's way of writing it, "normally"
>> it would look like:
>>
>> case Expr of
>>     Pat -> Expr ;
>>     or case Expr of
>>     Pat -> Expr ;
>>     Pat -> Expr ;
>>     or case ...
>>
>> Richard prefers using the separators as a form of keyword. You probably
>> don't need the extra 'or' though it might make it clearer.
>>
>> As an alternative suggestion is to have cond but to extend the test to
>> have a boolena match:
>>
>> cond
>>     test1() -> ... ;
>>     Pat = expr() -> ... ;
>>     ...
>> end
>>
>> and allow guards. It wouldn't be as versatile as the suggestion in the
>> EEP.
>>
>> Robert
>>
>>
>> _______________________________________________
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>> 
>> http://www.erlang.org/mailman/listinfo/eeps
>>
>
>
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