Lightweight linear types in system f°

  • Authors:

  • Karl Mazurak;Jianzhou Zhao;Steve Zdancewic

  • Affiliations:

  • University of Pennsylvania, Philadelphia, PA, USA;University of Pennsylvania, Philadelphia, PA, USA;University of Pennsylvania, Philadelphia, PA, USA

  • Venue:
  • Proceedings of the 5th ACM SIGPLAN workshop on Types in language design and implementation
  • Year:
  • 2010

Quantified Score

Hi-index 0.00

Visualization

Abstract

We present System F°, an extension of System F that uses kinds to distinguish between linear and unrestricted types, simplifying the use of linearity for general-purpose programming. We demonstrate through examples how System F° can elegantly express many useful protocols, and we prove that any protocol representable as a DFA can be encoded as an F° type. We supply mechanized proofs of System F°'s soundness and parametricity properties, along with a nonstandard operational semantics that formalizes common intuitions about linearity and aids in reasoning about protocols. We compare System F° to other linear systems, noting that the simplicity of our kind-based approach leads to a more explicit account of what linearity is meant to capture, allowing otherwise-conflicting interpretations of linearity (in particular, restrictions on aliasing versus restrictions on resource usage) to coexist peacefully. We also discuss extensions to System F^o aimed at making the core language more practical, including the additive fragment of linear logic, algebraic datatypes, and recursion.