Dynamic lazy type system

Patent metadata

Field	Value
Publication number	US-9081893-B2
Application number	US-201113163261-A
Country	US
Kind code	B2
Filing date	Jun 17, 2011
Priority date	Feb 18, 2011
Publication date	Jul 14, 2015
Grant date	Jul 14, 2015

Abstract

A dynamic, lazy type system is provided for a dynamic, lazy programming language. Consequently, programs can benefit from runtime flexibility and lightweight notation in combination with benefits afforded by a substantial type system.

First claim

What is claimed is:

1. A method, comprising:
employing at least one processor configured to execute computer-executable instructions stored in memory to perform the following acts;
identifying one or more types associated with an expression of a computer-executable program at runtime just prior to evaluation of the expression, wherein evaluation of the expression is deferred until a result of the expression is required;
determining that at least a portion of the program can be executed by a remote execution engine as a function of an identified type; and
translating at least a portion of the program to a target programming language for remote execution.

2. The method of claim 1 , further comprising evaluating one or more constraints specified by a type and returning a type error if at least one of the one or more constraints is unsatisfied.

3. The method of claim 2 , further comprising evaluating the one or more constraints over a base category.

4. The method of claim 1 , further comprising dynamically generating one or more types at runtime.

5. The method of claim 1 , further comprising predicting a result type of a function based on one or more function argument types.

6. The method of claim 1 , further comprising identifying a brand that specifies a constraint on a type.

7. A system, comprising:
a processor coupled to a memory, the processor configured to execute the following computer-executable components stored in the memory;
a first component configured to assign a type to an expression in a computer-executable program at runtime just prior to evaluation of the expression, wherein evaluation is deferred until a result of the expression is required; and
a set-based type system having a plurality of base categories, wherein a type corresponds to constraints with respect to a particular base category, the base categories include number, text, record, and list, and wherein type enforcement is performed lazily.

8. The system of claim 7 , further comprising a second component configured to analyze the program for errors as a function of the type during program execution.

9. The system of claim 7 , wherein the type specifies a constraint over a base category.

10. The system of claim 7 , wherein the type is represented as a value.

11. The system of claim 7 , wherein the type includes one or more operator definitions.

12. The system of claim 7 , wherein the type includes a brand that specifies a constraint on the type.

13. The system of claim 7 , wherein the type is a cross-category union type.

14. The system of claim 7 , wherein the type is derived from a number category that represents real numbers.

15. The system of claim 7 , wherein the first component is configured to assign a function result type based on function argument types.

16. A computer-readable storage medium having instructions stored thereon that enables at least one processor to perform a method upon execution of the instructions, the method comprising:
inferring one or more types associated with an expression of a computer program dynamically at runtime just prior to evaluation of the expression, wherein the evaluation is deferred until a result of the expression is required;
analyzing the program for errors as a function of the one or more types; and
acquiring one or more types from an external data source.

17. The computer-readable storage medium of claim 16 , wherein an inferred type specifies a constraint over a base category.

18. The computer-readable storage medium of claim 16 , wherein an inferred type is a cross-category union type.

19. The computer-readable storage medium of claim 16 , wherein an inferred type is derived from a number category that represents real numbers.

20. The computer-readable storage medium of claim 16 , wherein the inferring step infers a predicted result type of a function based on actual argument types, as opposed to declared parameter types.

Assignees

• Christensen Erik
• Coulson Michael
• Szyperski Clemens
• Hughes Gregory
• Microsoft Technology Licensing Llc

Inventors

• Christensen Erik
• Coulson Michael
• Szyperski Clemens
• Hughes Gregory

Classifications

• G06F8/437

  Type checking · CPC title

• G06F11/3612 Primary

  by runtime analysis (performance monitoring G06F11/3466) · CPC title

• G06F11/3608 Primary

  using formal methods, e.g. model checking, abstract interpretation (theorem proving G06N5/013) · CPC title

• G06F9/44589

  Program code verification, e.g. Java bytecode verification, proof-carrying code (high-level semantic checks G06F8/43; prevention of errors by analysis, debugging or testing of software G06F11/36) · CPC title