From: Bill <wherrera@...>
Date: 2004-10-12T14:14:36+09:00
Subject: Re: Ruby programming styles and new program?

Eivind Eklund wrote:
> 
> #
> # I'm not entirely sure about the inject rewrite here; just 
> # accumulating on moved may be just as good.
> #
> def archive_old_to_zip(backup_dir, base_log_name, t)
>      dir = Dir.open(backup_dir)
>      moved = dir.inject(0) do |lcount, ogfile|
>          # Skip-logic can use trailing conditionals
>          next unless logfile =~ /^CID/
>          next unless t > File.stat(logfile).mtime + ARCHIVE_DAYS_SECS
>          # Active logic use prefix if
>          if (move_to_archive(logfile))
>              next count + 1
>          else
>              next count
>          end
>      end
>      dir.close
>      return moved
> end
> 

Thanks for the suggestion to put the logging/archiving code in a class.
That refactoring does allow more appropriate data scoping.

One problem: I cannot find documentation for the Dir.inject method. I 
assume from some of the Ruby docs this is like the Smalltalk inject 
method, but I don't know why it's not documented in the Dir class?

Anyway, what, exactly, is happening in the line (typo removed)

 >      moved = dir.inject(0) do |count, logfile|

and how do you know to put the | count, logfile | variables in that 
order, and not | logfile, count | ?