From: Sean Chittenden <sean@...>
Date: 2002-07-09T17:17:40+09:00
Subject: Re: for ... else ... end

> |And by the way, the Pythonism originally referenced is
> |certainly more elegant than the throw/catch example. I
> |wonder if it's useful enough to consider including?
> |
> |Maybe it's one of those things you don't realize you need
> |until you have it.
> 
> But I don't feel "for .. else" is intuitive.  The "else" seem like
> indentation mistake rather than loop termination hook.  Maybe there
> can be a more suitable keyword.

Hmm...  I work around not having this construct constantly when doing
database work.  After talking with Holden about this on IRC, I think
the following examples are helpful.


dbh.select_all(sql) do |row|
  # do something with row
else
  puts "No rows returned!"
end

for elt in arr
  puts elt
else
  puts "No rows processed"
end



Which opens the door for:

for elt in arr
  puts elt
else
  puts "no rows"
ensure
  puts "done looping"
end


Hmm...  I think else is the correct word because it is short hand for
typing out:

if [].length > 0
  for elt in []
    puts elt
  end
else
  puts "now rows"
end
puts "done looping"

The example immediately above strikes me as a way of working around
the language, as opposed to the language doing what you want it to.
::shrug:: My $0.02.  -sc

-- 
Sean Chittenden