8. A system embodied on a computer readable storage medium that facilitates null support for programming language types, comprising: a nullable type that includes an underlying value of a type associated with at least one programming language and an indicator value that signals when an instance of the nullable type represents null; and a runtime component that provides runtime support for the nullable type, wherein the runtime component prevents execution of instances of a nullable type nested within another nullable type, and wherein the runtime component includes an identifier component that identifies the instance of the nullable type, and a conversion component that provides conversion between an instance of the nullable type and an instance of a reference type, and wherein conversion of the instance of the nullable type to an instance of a reference type includes unwrapping the instance of the nullable type, generating a reference to the underlying value when the indicator value signals that the instance of the nullable type does not represent null and generating a null reference when the indicator value signals that the instance of the nullable type represents null.
8. A system embodied on a computer readable storage medium that facilitates null support for programming language types, comprising: a nullable type that includes an underlying value of a type associated with at least one programming language and an indicator value that signals when an instance of the nullable type represents null; and a runtime component that provides runtime support for the nullable type, wherein the runtime component prevents execution of instances of a nullable type nested within another nullable type, and wherein the runtime component includes an identifier component that identifies the instance of the nullable type, and a conversion component that provides conversion between an instance of the nullable type and an instance of a reference type, and wherein conversion of the instance of the nullable type to an instance of a reference type includes unwrapping the instance of the nullable type, generating a reference to the underlying value when the indicator value signals that the instance of the nullable type does not represent null and generating a null reference when the indicator value signals that the instance of the nullable type represents null. 9. The system of claim 8 , the conversion component provides for the conversion of the instance of the reference type to at least one of the instance of the nullable type and an instance the type of the underlying value.