state_machine

StateMachine::EvalHelpers#evaluate_method

Evaluates one of several different types of methods within the context
of the given object.  Methods can be one of the following types:
* Symbol
* Method / Proc
* String

== Examples

Below are examples of the various ways that a method can be evaluated
on an object:

  class Person
    def initialize(name)
      @name = name
    end
    
    def name
      @name
    end
  end
  
  class PersonCallback
    def self.run(person)
      person.name
    end
  end

  person = Person.new('John Smith')
  
  evaluate_method(person, :name)                            # => "John Smith"
  evaluate_method(person, PersonCallback.method(:run))      # => "John Smith"
  evaluate_method(person, Proc.new {|person| person.name})  # => "John Smith"
  evaluate_method(person, lambda {|person| person.name})    # => "John Smith"
  evaluate_method(person, '@name')                          # => "John Smith"

== Additional arguments

Additional arguments can be passed to the methods being evaluated.  If
the method defines additional arguments other than the object context,
then all arguments are required.

For example,

  person = Person.new('John Smith')
  
  evaluate_method(person, lambda {|person| person.name}, 21)                              # => "John Smith"
  evaluate_method(person, lambda {|person, age| "#{person.name} is #{age}"}, 21)          # => "John Smith is 21"
  evaluate_method(person, lambda {|person, age| "#{person.name} is #{age}"}, 21, 'male')  # => ArgumentError: wrong number of arguments (3 for 2)

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