From: James Edward Gray II <james@...>
Date: 2005-07-12T02:03:00+09:00
Subject: Standard Library Warnings

I keep running into some warning message from standard libraries.  I  
always use warnings so they are driving me crazy.

With the latest release of HighLine, I actually had to build a work- 
around that captures, disables, and later resets the warning level  
when calling into readline, because it's my opinion that the warning  
breaks auto-completion (the warning appears in the middle of your  
completed word).

Given that, I thought I would post some warning firing examples in  
the attempt to get some Ruby core hacker to feel sorry for me and  
apply a patch or two.  I looked at patching set.rb myself but it  
seems that there is a hack in there to work around this warning and I  
couldn't figure out why it doesn't work.

Here are my examples:

$ ruby -v
ruby 1.8.2 (2004-12-25) [powerpc-darwin7.7.0]
$ cat set_example.rb
require "set"

SortedSet.new
$ ruby -w set_example.rb
(eval):2: warning: method redefined; discarding old initialize
$ cat prog_ruby_example_723.rb
# Sample code from Programing Ruby, page 723
require 'readline'
include Readline

require 'abbrev'

COMMANDS = %w{ exit inc dec }

ABBREV = COMMANDS.abbrev

Readline.completion_proc = proc do |string|
   ABBREV[string]
end

value = 0

loop do

   cmd = readline("wibble [#{value}]: ", true)

   break if cmd.nil?

   case cmd.strip
   when "exit"
     break
   when "inc"
     value += 1
   when "dec"
     value -= 1
   else
     puts "Invalid command #{cmd}"
   end

end
$ ruby -w prog_ruby_example_723.rb
wibble [0]: dprog_ruby_example_723.rb:19: warning: instance variable  
completion_case_fold not initialized
ec

In that last example, I pushed d then tab to trigger the warning.

Let me know if I can answer any questions and thanks in advance for  
taking pity on a warnings-allergic coder.

James Edward Gray II