module Endless

	def If(f)
		if(f)
			yield
			return EndlessIfTrue.new()
		else
			return EndlessIfFalse.new()
		end
	end
	
	def Unless(f)
		unless(f)
			yield
			return EndlessIfTrue.new()
		else
			return EndlessIfFalse.new()
		end
	end

	def Do()
		w = EndlessDo.new()
		callcc{|c| w.setCont(c)}
		yield
		return w
	end

	def Case(v)
		return EndlessCaseFalse.new(v)
	end

end




class EndlessIfTrue
	def Elsif(f) return EndlessIfTrue.new() end
	def Else() return EndlessIfTrue.new() end
end


class EndlessIfFalse
	def Elsif(f)
		if(f)
			yield
			return EndlessIfTrue.new()
		else
			return EndlessIfFalse.new()
		end
	end

	def Else()
		yield
		return EndlessIfTrue.new()
	end
end



class EndlessDo
	@cont = false
	def setCont(c)
		@cont = c
	end
	
	def While(f)
		if(f)
			@cont.call()
		end
	end

	def Until(f)
		unless(f)
			@cont.call()
		end
	end
end


class EndlessCaseTrue
	def When(f) return EndlessCaseTrue.new() end
	def Else() return EndlessCaseTrue.new() end
end


class EndlessCaseFalse
	@value = false
	def initialize(v)
		@value = v
	end
	
	def When(f)
		if (f.class() == Range && f.include?(@value))
			yield
			return EndlessCaseTrue.new()
		elsif (f == @value)
			yield
			return EndlessCaseTrue.new()
		else
			return EndlessCaseFalse.new(@value)
		end
	end
	
	def Else()
		yield
		return EndlessCaseTrue.new()
	end
end