From: Gavin Kistner <gavin@...>
Date: 2005-06-12T00:45:56+09:00
Subject: Only if the object exists

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If I write code like this:
   self.foo.bar if self.foo
then ruby runs the #foo method twice. (Javascript is the same way.)

If #foo is a lengthy process which I know has no side-effects, this  
is wasteful. But, I need to ensure that #foo didn't return nil. I  
have (at least) three choices:

   if ( tmp=foo )
     puts tmp.bar
   end

   ( tmp=foo ) && ( puts tmp.bar )

   puts tmp.bar if ( tmp=foo )

...except that the last doesn't work, if 'tmp' has not been  
previously seen as a local variable. Unfortunately, that's the form  
that I really think looks best.


Would it be possible to have the parser recognize the single-line 'if/ 
unless' case and process the right side before the left side (the  
order in which the code is executed)?


--
"When I am working on a problem I never think about beauty. I only  
think about how to solve the problem. But when I have finished, if  
the solution is not beautiful, I know it is wrong."
- R. Buckminster Fuller


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