From: Saverio Miroddi <saverio.pub2@...>
Date: 2011-01-15T18:52:22+09:00
Subject: Re: Normal For Loop

> I tried to do this the other night, but right now I can't find a good
> example so here it goes:
>
> a = some_array
> minValue = 999999
> for(i=0; i<a.length && minValue!=0; i+=1) {
>    minValue = (5000 - a[i]).abs
> }
>
>
> This isn't the best example.  However, there are many times like the
> loop above where I want to go through the whole thing, but if I find
> exactly what I am looking for, I want to bail out early instead of
> wasting that processing time.
>
> Also, I sometimes may want to not actually iterate straight through, but
> browse through the array in some more complex order.

I have a "good" example. In my case I want to iterate a collection, 
skipping a variable number of elements based on a given element.
In this case, the C for construct (counter_init, cycle_condition,) would 
be useful because I wouldn't have to initialize the counter variable 
outside of the scope, and I can increment the counter inside the loop.

The code is something like this:

for ( i = 0; i < elements.size; ) do
  if elements[ i ].is_a?( OneType )
    do_operation( elements[ i ] );
    i += 1;
  elsif elements[ i ].is_a?( AnotherType )
    sub_elements = []
    begin
      sub_elements << elements[ i
      i += 1;
    end while elements[ i ].is_a?( AnotherType )
    do_another_operation( sub_elements )
  else
    ...
  end
end

This example doesn't pretend to be clever/correct/well constructed, but 
is a real-world case where this kind of loop would be useful.

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