Abstract: Utilizing role types that extend underlying types. Within a program definition, a computer system identifies a statement assigning an object of an underlying type to a role type that extends the underlying type. The underlying type implements a first interface, and the role type implements a second interface. Based on the role type extending the underlying type, the computer system assigns the object of the underlying type to the role type. Based on assigning the object of the underlying type to the role type, the role type is usable to interact with the object of the underlying type using both the first interface and the second interface.

Abstract: A language extension that advances safety in system programming in that an entire type may be declared to be immutable in the case in which all instances of that type are immutable. The immutable type declaration automatically causes any instances of that type to be treated as immutable, and automatically causes all directly or indirectly reachable members (e.g., fields, methods, properties) of the instance to also be treated as immutable. Furthermore, any construction time reference that allows for field assignment of the instance is not permitted to survive beyond the point at which the instance becomes accessible to its creator. Accordingly, this instance, and any other instance of that same type, will be immutable from the very time of construction. The ability to classify all such instances as immutable is beneficial as the immutable characteristic permits actions that normally would not be allowed due to resource access safety.

Abstract: A front-end compiler compiles source code into intermediate code, that may later be compiled into binary code. The source code defines an execution scope and includes a contract. When a contract is encountered at runtime of an execution scope, further execution of that execution scope is conditioned on whether a predicate associated with the contract is true. The front-end compiler operates so as to preserve the contract so that the contract continues to be semantically structured such that the predicate may be removed from the intermediate language code. The contract may thus continue to be understood by semantic analysis of the contract. Thus, the predicate may be understood by static analysis tools that operate on the intermediate code.

Abstract: The type definition of particular types such that different portions of the corresponding object graph may have different permissions assigned to those portions during instantiation. This allows structured permissions to be applied to instantiations of the object graphs of those defined types, allowing fine grained control over what access permissions are enforced against which portions of the object graph. In some embodiments, different instantiations of the object graph may apply permissions differently.

Abstract: A language extension that advances safety in system programming in that an entire type may be declared to be immutable in the case in which all instances of that type are immutable. The immutable type declaration automatically causes any instances of that type to be treated as immutable, and automatically causes all directly or indirectly reachable members (e.g., fields, methods, properties) of the instance to also be treated as immutable. Furthermore, any construction time reference that allows for field assignment of the instance is not permitted to survive beyond the point at which the instance becomes accessible to its creator. Accordingly, this instance, and any other instance of that same type, will be immutable from the very time of construction. The ability to classify all such instances as immutable is beneficial as the immutable characteristic permits actions that normally would not be allowed due to resource access safety.

Abstract: A language extension that advances safety in system programming in that an entire type may be declared to be immutable in the case in which all instances of that type are immutable. The immutable type declaration automatically causes any instances of that type to be treated as immutable, and automatically causes all directly or indirectly reachable members (e.g., fields, methods, properties) of the instance to also be treated as immutable. Furthermore, any construction time reference that allows for field assignment of the instance is not permitted to survive beyond the point at which the instance becomes accessible to its creator. Accordingly, this instance, and any other instance of that same type, will be immutable from the very time of construction. The ability to classify all such instances as immutable is beneficial as the immutable characteristic permits actions that normally would not be allowed due to resource access safety.

Abstract: A front-end compiler compiles source code into intermediate code, that may later be compiled into binary code. The source code defines an execution scope and includes a contract. When a contract is encountered at runtime of an execution scope, further execution of that execution scope is conditioned on whether a predicate associated with the contract is true. The front-end compiler operates so as to preserve the contract so that the contract continues to be semantically structured such that the predicate may be removed from the intermediate language code. The contract may thus continue to be understood by semantic analysis of the contract. Thus, the predicate may be understood by static analysis tools that operate on the intermediate code.

Abstract: The type definition of particular types such that different portions of the corresponding object graph may have different permissions assigned to those portions during instantiation. This allows structured permissions to be applied to instantiations of the object graphs of those defined types, allowing fine grained control over what access permissions are enforced against which portions of the object graph. In some embodiments, different instantiations of the object graph may apply permissions differently.

Abstract: A language extension that advances safety in system programming by specifying a lifetime of a reference that represents a resource. In accordance with the language extension, the lifetime references a particular scope in a manner that the compiler generates computer-executable instructions that enforce the lifetime of the reference to be a function of (e.g., no longer than) the lifetime of the particular scope. Accordingly, the resource lifetime may be specified in advance to have a particular scope. This helps in performing resource management as typical managed language programs can allow resources to exist indefinitely. Furthermore, because the resources have a defined finite lifetime, they might be more conveniently allocated on a stack, instead of on a heap, for much more efficient processing.

Abstract: A language extension that advances safety in system programming in that an entire type may be declared to be immutable in the case in which all instances of that type are immutable. The immutable type declaration automatically causes any instances of that type to be treated as immutable, and automatically causes all directly or indirectly reachable members (e.g., fields, methods, properties) of the instance to also be treated as immutable. Furthermore, any construction time reference that allows for field assignment of the instance is not permitted to survive beyond the point at which the instance becomes accessible to its creator. Accordingly, this instance, and any other instance of that same type, will be immutable from the very time of construction. The ability to classify all such instances as immutable is beneficial as the immutable characteristic permits actions that normally would not be allowed due to resource access safety.