From: Ilmari Heikkinen <kig@...>
Date: 2005-01-21T04:10:02+09:00
Subject: Re: Confused about variable "declarations"


On 20.1.2005, at 20:53, Nicholas Van Weerdenburg wrote:
>> This may be the leaky case:
>>
>> x = 10
>> arr = (x..100).map{|x| x*2}
>> x #=> 100
>>
>> :)
>>
>> --
>> Ilmari Heikkinen
>>
>>
>
> I'm quite fond of this behaviour. It works nicely in the "optparse" 
> library.
>
> e.g.
> require "optparse"
> logfile=nil;
> opts=OptionParser.new do |opt|
>     opt.on('--logfile', '-l', "Specify log file"){|logfile|}
> end
>

My main squabble with that is that there is no explicit assignment 
going on. By reading the code out of context, you'd never know if it 
has side-effects or not.

The non-obfuscated way would be:

   opt.on('--logfile','-l',"Specify log file"){|o| logfile = o}

or the even shorter than {|logfile|} (no idea if opt.on does this, but 
anyhow):

   logfile = opt.on('--logfile','-l',"Specify log file")

Those make it clear that logfile is being changed.

--
Ilmari Heikkinen