Type Inference of SELF Analysis of Objects with Dynamic and Multiple Inheritance.pdfVIP

Type Inference of SELF Analysis of Objects with Dynamic and Multiple Inheritance∗ Ole Agesen† Jens Palsberg agesen@ palsberg@daimi.aau.dk Michael I. Schwartzbach‡ mis@daimi.aau.dk April 1993 Dept. of Computer Science Computer Science Department Stanford University Aarhus University ˚ Stanford, CA 94305 Ny Munkegade, DK − 8000 Arhus C USA Denmark Abstract We have designed and implemented a type inference algorithm for the full Self language. Thc algorithm can guarantee the safety and disambiguity of message sends, and provide useful information for browsers and optimizing compilers. Self features objects with dynamic inheritance. This construct has until now been considered incompatible with type inference be- cause it allows the inheritance graph to change dynamically. Our ∗This paper will be presented at ECOOP’93. References should cite the proceedings. †Generously supported by National Science Foundation Presidential Young Investigator Grant #CCR-8657631, by Sun Microsystems, IBM, Apple Computer, Cray Laboratories, Tandem Computer, NCR, Texas Instruments, DEC, by a research fellowship from the Natural Science Faculty of Aarhus University, and by the Danish Research Academy. ‡Partially supported by the Danish Research Counsil, DART Project (5.21.08.03). 1 algorithm handles this by deriving and solving type constraints that simultaneously define supersets of both the possible values of ex