Example of variable re-evaluation after setter usage in ConfigSet.

config_set_var_re-eval_example.rb

# Set some values...
config = ConfigSet.for('routes') {
  host "codeforpeople.com"
  port 80

  signup_url "http://#{ host }/signup"
  signout_url "http://#{ port }/signout"

  app {
    signup_url "http://#{ host }/signup"
  }
}

# Current values...
config.host.should == "codeforpeople.com"
config.signup_url.should == "http://codeforpeople.com/signup"

# Reset host using it's setter outside of the block.
config.host = "apple.com"

# Now this is true...
config.host.should == "apple.com"

# Child re-evaluates because config.host changed!!!
config.signup_url.should == "http://apple.com/signup"

# Of course this is left untouched since it doesn't use config.host...
config.signout_url.should == "http://80/signout"

# Nested values are untouched as well, because they are out of scope.
# Though I guess I could allow it, the code's there it's just blocked.
config.app.signup_url.should == "http://codeforpeople.com/signup"
config.app.host.should == 'codeforpeople.com'

I swear to god this works and it was pretty easy once I got the logic right. I'm just not sure how useful it is or if I'll include it.

It also increases the line number of the class by like 20 to 75 lines of total code.