From: Kevin Nolan <kpnolan@...>
Date: 2008-08-15T02:51:38+09:00
Subject: Best practice for set-and-test idiom?

I've been using Ruby/Rails for about about four months and wonder what
the the Ruby alternative to the popular C/C++ idiom of setting and
testing a variable in the condition of an 'if' statement. If C/C++ the
usage is typically:

     if ((ptr = fcn_returning_ptr(...)) == NULL) {
       val = ptr->ref
     } else {
       val = DEFAULT
     }

   or the compact version:

     val = (ptr = fcn_returning_ptr(...)) ? ptr->ref : DEFAULT

Which, when I translate to Ruby yields (ActiveRecord example):

     unless (ar = Model.find(...)).nil?
        val = ar.attribute
     else
        val = DEFAULT

   or the equivalent expression.

It seems to me that this is very unRuby-like and I don't see any similar
usages in any of the code-bases in which I have looked.

Will someone please provide a counter-example?

Thanks,

kevin nolan
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