Extensible type system for representing and checking consistency of program components during the process of compilation

• US 7,086,041 B2
• Filed: 06/27/2003
• Issued: 08/01/2006
• Est. Priority Date: 06/27/2003
• Status: Expired due to Fees

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Tarditi, David Read Jr., Plesko, Mark Ronald
• Primary Examiner(s): CHAVIS, JOHN Q
• Application Number:
  US10/607,601
• Publication Number:
  US 20040268328A1
• Time in Patent Office: 1,131 Days
• Field of Search: 717/141
• US Class Current: 717/141
• CPC Class Codes: G06F 8/437 Type checking

Abstract

A representation of types, type-checker, and compiler are provided for checking consistency in various forms of an intermediate language. Type-checking a programming language in a compiler is accomplished by taking one or more rule sets as input to a type-checker, which selects one or more of the rule sets based upon any one, or combination of two or more, of numerous criteria. Among them are stage of compilation, source language, architecture, and level of typing present in the language being type-checked. The language is then type-checked using the selected one or more rule sets. The rule sets can include one rule set corresponding to strong type-checking, one rule set corresponding to weak type-checking, and one rule set corresponding to representation type-checking. In the alternative, a compiler can be provided with a type-checker that constructs the one or more sets of rules at runtime from a larger set of rules based on any one, or combination of two or more, of the previously mentioned criteria.

Claims

1. A method of type-checking a programming language in a compiler according to one or more rule sets comprising:

selecting one or more of the rule sets based upon the present stage of compilation; and

type-checking the programming language based on the selected one or more rule sets;

wherein the one or more rule sets comprise one rule set corresponding to strong type-checking, one corresponding to weak type-checking, and one corresponding to representation type-checking.

2. The method of claim 1 wherein type-checking the programming language comprises type-checking each of a plurality of intermediate representations of the programming language.

3. The method of claim 2 wherein the selected one or more rule sets are different for each representation.

4. The method of claim 1 wherein the programming language includes a type that indicates an element of the programming language can be one of a plurality of types.

5. The method of claim 4 wherein the one or more rule sets contains rules for type-checking a type that indicates an element of the programming language can be one of a plurality of types.

6. The method of claim 1 wherein the one or mare rule sets comprise a plurality of rules in a hierarchical format.

7. The method of claim 1 wherein the representation type-checking will allow dropped type information for elements of the programming language.

8. The method of claim 1 wherein the weak type-checking will allow type casting.

9. A compiler for compiling source code written in a source language comprising:

a plurality of type rules; and

a type-checker that selects a subset of type rules from the plurality of type rules based upon the source language to construct a rule set;

wherein three rule sets are constructed;

one corresponding to strong type-checking, one corresponding to weak type-checking, and one corresponding to representation type-checking.

10. The compiler of claim 9 wherein the representation type-checking will allow dropped type information for elements of the source code.

11. The compiler of claim 9 wherein the weak type-chccking will allow type casting.