Which programming languages support states on the language-level?

Question

UnrealScript has always impressed me, somewhat, with it its intrinsic support for states (and latent functions) by grouping/overloading functions and fields into blocks like:

state() SomeState
{
    ...
    function void Foo()
    {
        GotoState('SomeOtherState');
    }
    ...
}

Which is quite a bit cleaner than using loads of switch-statements inside every function (it's almost some sort of design by contract).

Are there any other more general-purpose programming languages that intrinsically support state declarations similar to this (ignoring visual programming languages or tools like Workflow Foundation)?

Edit:

Some of the beauty of states in UnrealScript is that you can override stateful functions in subclasses, and even define new, named states. I think this is troublesome to do with enum-switches (where enums cannot be extended), delegates, or co-classes implementing different states, especially in languages like C# or Java that only support single-inheritance.

Answer 1

Any object oriented programming language enables you to create state-machines easily. But you might want to take a look at QT and it's http://labs.trolltech.com/blogs/2009/01/30/qt-state-machine-framework/. I haven't tried it though.

I prefere languages that enable me to create a variety of supporting structures of my choice to languages that offer me special functionality for all different kinds of special situations. C++ as shown in QT is a good example for that.

Answer 2

None that I know of, but language that support easy writing of domain-specific languages through metaprogramming (e.g., Ruby), can essentially pretend to. From the acts_as_state_machine plugin for Rails:

class Nonprofit < ActiveRecord::Base
  acts_as_state_machine :initial => :created, :column => 'status'

  # These are all of the states for the existing system.
  state :submitted
  state :processing
  state :nonprofit_reviewing
  state :accepted

  event :accept do
    transitions :from => :processing,          :to => :accepted
    transitions :from => :nonprofit_reviewing, :to => :accepted
  end

  event :receive do
    transitions :from => :submitted, :to => :processing
  end

  # either a CTP  or nonprofit user edits the entry, requiring a review
  event :send_for_review do
    transitions :from => :processing,          :to => :nonprofit_reviewing
    transitions :from => :nonprofit_reviewing, :to => :processing
    transitions :from => :accepted,            :to => :nonprofit_reviewing
  end
end

(you can also include any arbitrary code in the event blocks, not just state transitions)