From: Joel VanderWerf <vjoel@...>
Date: 2003-12-09T16:20:27+09:00
Subject: Re: rbconfig suggestion: ruby_apps

Yukihiro Matsumoto wrote:
> In message "rbconfig suggestion: ruby_apps"
>     on 03/12/09, Joel VanderWerf <vjoel@PATH.Berkeley.EDU> writes:
> 
> |My particular reason is for a script that switches symlinks from 
> |ruby->ruby-1.7.3 to ruby->1.8.1p3 and so on.
> 
> ./configure --program-suffix=-1.8.1p3 will do.
> 
> 							matz.

:-) That's exactly what I do whenever a new snapshot comes out. Then 
with my little "switchruby" script I can change what my symlinks named 
ruby, irb, and so on point to. And change back again. Sample session:

# switchruby 1.7.3
ruby -> ruby-1.7.3
irb -> irb-1.7.3
erb -> erb-1.7.3
# switchruby
Current versions are:
   ruby -> ruby-1.7.3
   irb -> irb-1.7.3
   erb -> erb-1.7.3
   rdoc -> rdoc-1.8.1p3
   testrb -> testrb-1.8.1p3
Choices are: 1.7.3 1.8.0 1.8.1-22Nov03 1.8.1p3
# switchruby 1.8.1p3
ruby -> ruby-1.8.1p3
irb -> irb-1.8.1p3
erb -> erb-1.8.1p3
rdoc -> rdoc-1.8.1p3
testrb -> testrb-1.8.1p3

Of course, switching to 1.8.0 doesn't work so well because:

# ruby -r rbconfig -e 1
/usr/local/lib/ruby/1.8/i686-linux/rbconfig.rb:7: ruby lib version 
(1.8.1) doesn't match executable version (1.8.0) (RuntimeError)

I guess I could swap the lib dirs as well, but that's getting to be too 
much work, and besides I'm really more interested in switching between 
different previews or cvs of the same "teeny" version.

== switchruby ==

#!/usr/local/bin/ruby-1.7.3

require 'rbconfig'

ext = ARGV[0]

Dir.chdir Config::CONFIG["bindir"]

exts = []
Dir["ruby*"].grep(/^ruby-(.*)/) { |f| exts << $1 }

ruby_apps = ["ruby", "irb", "erb", "rdoc", "testrb"]
   # this should be provided by rbconfig.rb

if ext
   unless exts.include? ext
     $stderr.puts "Choices are: #{exts.join(" ")}"
     exit -1
   end

   extstr = ext.sub(/^(?!-)/, "-")

   ruby_apps.each do |app|
     target = app + extstr
     if File.exist? target
       if File.exist?(app) and not File.symlink?(app)
	$stderr.puts "File #{app} exists and is not a symlink. Aborting."
	exit -1
       end
       File.delete(app) and File.symlink(target, app) and
         puts "#{app} -> #{target}"
     end
   end

else

   cur =
     ruby_apps.map do |app|
       "  " + `ls -l #{app}`[/\w+ -> .*/]
     end

   puts "Current versions are:", cur

   puts "Choices are: #{exts.join(" ")}"

end