module ConfigVar

Define required and optional configuration variables and load them from the environment. Returns a configuration object that can be treated like a Hash with values available using lowercase symbols. For example, a PORT value from the environment can be accesses as config.port in the returned object. Booleans are only considered valid if they are one of '0', '1', 'true' or 'false'. The values are case insensitive, so 'TRUE', 'True' and 'TrUe' are all valid booleans.

Example:

config = ConfigVar.define do
  required_string  :database_url
  required_int     :port
  required_bool    :enabled
  optional_string  :name,         'Bob'
  optional_int     :age,          42
  optional_bool    :friendly,     true
end

# File lib/configvar.rb, line 20
def self.define(&blk)
  context = ConfigVar::Context.new
  context.instance_eval(&blk)
  context.reload(ENV)
  context
end