[Pl-seminar] 9/29 Seminar: Philipp Haller, LaCasa: Lightweight Affinity and Object Capabilities in Scala

[Daniel Patterson]

NUPRL Seminar presents

Philipp Haller
KTH Royal Institute of Technology


12:30--1:30pm
Thursday, Sept. 29 2016
Room 366 WVH (http://www.ccs.neu.edu/home/wand/directions.html)

LaCasa: Lightweight Affinity and Object Capabilities in Scala

Abstract:
Aliasing is a known source of challenges in the context of imperative
object-oriented languages, which have led to important advances in type
systems for aliasing control. However, their large-scale adoption has
turned out to be a surprisingly difficult challenge. While new language
designs show promise, they do not address the need of aliasing control in
existing languages.

This paper presents a new approach to isolation and uniqueness in an
existing, widely-used language, Scala. The approach is unique in the way it
addresses some of the most important obstacles to the adoption of type
system extensions for aliasing control. First, adaptation of existing code
requires only a minimal set of annotations. Only a single bit of
information is required per class. Surprisingly, the paper shows that this
information can be provided by the object-capability discipline,
widely-used in program security. We formalize our approach as a type system
and prove key soundness theorems. The type system is implemented for the
full Scala language, providing, for the first time, a sound integration
with Scala’s local type inference. Finally, we empirically evaluate the
conformity of existing Scala open-source code on a corpus of over 75,000
LOC.

Bio:
Philipp Haller is an assistant professor in the theoretical computer
science group at KTH Royal Institute of Technology, the leading technical
university in Sweden. His main research interests are programming
languages, type systems, concurrent, and distributed programming. Philipp
is co-author of Scala's async/await extension for asynchronous
computations, and one of the lead designers of Scala's futures and promises
library. As main author of the book "Actors in Scala," he created Scala's
first widely-used actors library. Philipp was co-chair of the 2013 and 2014
editions of the Scala Workshop, and co-chair of the 2015 ACM SIGPLAN Scala
Symposium. Previously, he has held positions at Typesafe, Stanford
University, and EPFL. He received a PhD in computer science from EPFL in
2010.
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