closure.rb

# Examples 9 & 10 from http://innig.net/software/ruby/closures-in-ruby.rb

def f(closure)
    puts
    puts "About to call closure"
    result = closure.call
    puts "Closure returned: #{result}"
    "Value from f"
end

begin
    f(Proc.new { return "Value from Proc.new" })
rescue Exception => e
    puts "Failed with #{e.class}: #{e}"
end

console.txt

Chuck-Remess-Mac-Pro:ruby cremes$ rvm default
Chuck-Remess-Mac-Pro:ruby cremes$ ruby -v
ruby 1.9.2p136 (2010-12-25 revision 30365) [x86_64-darwin10.5.0]
Chuck-Remess-Mac-Pro:ruby cremes$ ruby closure_crash.rb 

About to call closure
Failed with LocalJumpError: unexpected return
Chuck-Remess-Mac-Pro:ruby cremes$ rvm system
Chuck-Remess-Mac-Pro:ruby cremes$ rbx -v
rubinius 2.0.0dev (1.8.7 a9d31fef yyyy-mm-dd JI) [x86_64-apple-darwin10.8.0]
Chuck-Remess-Mac-Pro:ruby cremes$ rbx closure_crash.rb 

About to call closure