Microsoft Technology Licensing, LLC

Joseph Pamer

Anders Hejlsberg

Steven E Lucco

Mads Torgersen

Charles P Jazdzewski

Lucas James Hoban

A hostable compiler interacts with a host application to enable the host application to execute program code supported by the hostable compiler. The host application and the hostable compiler exchange data through an interface that allows the hostable compiler to receive type information pertaining to data elements used applications executing within the host application process. This type information may then be used by the hostable compiler in the compilation of source code to infer a type for data elements used in the source code that are not declared yet associated with a value of an expression used in an application executed within the host application process.

Hostable compiler utilizing type information from a host application

The type environment of a program can be modeled as a graph. In the graph, a node can represent a code element including but not limited to a function, a class, an object, a variable, an expression, a script, a global, a primitive, a module, an interface, an enumerated list, an array, an alias for a type, a parameter, a property, a type, a method, a function expression, a call signature, an index signature, an object type, or a function type. An edge in the graph can represent a relationship between code elements. When the type of a code element changes, the graph can be changed to model the revised source code. Computations concerning effects of a type change are delayed until information concerning the affected code element is requested.

Graph-based model for type systems

Static type checking can be performed on types and values defined in modules in a system that dynamically composes programs from modules. The types and values do not share a global namespace. Each module defines its own module universe, disjoint from other modules. A language mechanism can establish a local name binding to one module within the content of another module. When type checking at compile time an environment can be established that corresponds to a runtime instance of the program. The static type system can be arranged to align with the runtime values, such that the names used to refer to objects at runtime are the same as the names used to refer to the types of those objects in the static type system. Aliases of a particular type are resolved to a known compile time description of the type.

Static type checking across module universes

Type inference is used to provide the benefits of static type checking without explicitly declaring type in the source code. Type inference that proceeds in a bottom up direction is augmented by contextual typing that proceeds in a top down direction. Contextual typing types enclosed expressions by associating the type of a directly enclosing expression with the enclosed expression. Object literals, function literals and array literals enclosed in assignment and call expressions, can be contextually typed.

Contextual typing

Statically extensible types allow a static type system to model the behavior of dynamic object model extension in dynamic runtime systems. Static types that model dynamically extended types can be extended using additional declarations in the same compilation. Declarations for a particular type can come from multiple independent sources which can have been defined at multiple points in time. Extension declarations can use the same syntax as the initial type declaration. Hence presence of one or more declarations for the same type in a compilation can indicate that the type has been extended. These features allow static type checking of dynamic plug-ins to be supported using statically extensible types. Declarations and extension declarations for a type can be merged together to create an extended type that enables different processing paths and dependencies.

Statically extensible types

A hostable compiler interacts with a host application to enable the host application to execute program code supported by the hostable compiler. The host application and the hostable compiler exchange data through an interface that allows the hostable compiler to receive type information pertaining to data elements used in applications executing within the host application process. This type information may then be used by the hostable compiler in the compilation of source code to infer a type for data elements used in the source code that are not declared yet associated with a value of an expression used in an application executed within the host application process.

Growing community of inventors

Seattle, WA, United States of America

Joseph Pamer