Uniqueness Typing for Resource Management in Message-Passing Concurrency

We view channels as the main form of resources in a message-passing programming paradigm. These channels need to be carefully managed in settings where resources are scarce. To study this problem, we extend the pi-calculus with primitives for channel allocation and deallocation and allow channels to be reused to communicate values of different types. Inevitably, the added expressiveness increases the possibilities for runtime errors. We define a substructural type system which combines uniqueness typing and affine typing to reject these ill-behaved programs

Better Static Memory Management: Improving Region-Based Analysis of Higher-Order Languages (Extended Abstract)

) Alexander Aiken Manuel F ahndrich Raph Levien y Computer Science Division University of California, Berkeley z Abstract Static memory management replaces runtime garbage collection with compile-time annotations that make all memory allocation and deallocation explicit in a program. We improve upon the Tofte/Talpin region-based scheme for compile-time memory management [TT94]. In the Tofte/Talpin approach, all values, including closures, are stored in regions. Region lifetimes coincide with lexical scope, thus forming a runtime stack of regions and eliminating the need for garbage collection. We relax the requirement that region lifetimes be lexical. Rather, regions are allocated late and deallocated as early as possible by explicit memory operations. The placement of allocation and deallocation annotations is determined by solving a system of constraints that expresses all possible annotations. Experiments show that our approach reduces memory requirements significantly, in som..

Dynamic Typing and Subtype Inference

Dynamic typing is a program analysis targeted at removing runtime tagging and untagging operations from programs written in dynamically typed languages. This paper compares dynamic typing with a subtyping system based on set constraints. The purpose is both to make precise the relationship between two superficially unrelated type systems and to illustrate how the advantages of dynamic typing and subtype inference can be combined. The central result is a theorem showing that a typing discipline at least as powerful as dynamic typing can be expressed using set constraints. 1 Introduction This paper presents a study of Henglein's dynamic typing discipline [Hen92a, Hen92b]. Dynamic typing extends conventional static types with a single new type Dynamic. Special functions called coercions inject values into and project values from type Dynamic. Currently, the main application of dynamic typing is the optimization of programs written in dynamically typed languages (such as Lisp and Schem..