From: Eric Mahurin <eric_mahurin@...>
Date: 2005-05-12T04:59:12+09:00
Subject: object loops and what they return

Consider these loops:

<object>.<loop-method> { <code> }

where loop method is each, each_with_index, upto, downto, step,
and probably others.

Although it is not documented, all of these look to return the
origninal object (collection or int).  Does anybody find this
useful??  If not, I would propose that these return nil just
like loop, while, until, begin/end while, and begin/end until. 
I've never found the return value of these methods useful, but
I have found the the built-in loops returning nil useful.  Here
are a couple:

# find first index where you find the object obj in array
index = array.each_with_index do |i,x|
    break(i) if obj.equal?(x)
end

# find last index where you find the object obj in array
index = (array.size-1).downto(0) do |i,x|
    break(i) if obj.equal?(x)
end

The problem with the above now is that index will be the loop
object (array and array.size-1 from above) when you don't find
the obj.  Instead of the above, I end up using old-style loops
to accomplish what I want.

With "each" returning nil, you can also see that many of the
derived loops in Enumerable become trival almost to where you
don't need them.



		
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