From: Christian Boos <cboos@...>
Date: 2006-02-03T19:30:08+09:00
Subject: Re: ruby-dev summary 28206-28273

ara.t.howard@noaa.gov wrote:
> On Thu, 2 Feb 2006, Minero Aoki wrote:
>
>> [ruby-dev:28217] ANDCALL operator
>>
>>  Nobuyoshi Nakada suggested a new operator `&?' (this notation is 
>> temporary)
>>  which evaluates left-hand-side expression, and if it is true then call
>>  right-hand-side method.  For example:
>>
>>    if a[1] and a[1].strip.empty?
>>                ||
>>    if a[1] &? strip.empty?
>>
>>    h["key"] and h["key"].dispatch
>>                ||
>>    h["key"] &? dispatch
>>
>>  The motivation of this operator is to avoid duplication of expression.

I usually write those as:

 if (elt = a[1]) and elt.strip.empty?

and

(k = h["key"]) and k.dispatch

... assuming it costs nothing to create a new temporary variable.

But if Nobu's idea catches on, I'd rather suggest extending the syntax
to allow for conditional method call (using .?), as I find the above
notation (&?) too confusing.

-- Christian