This volume contains the proceedings of the 6th Asian Symposium on Progr- ming Languages and Systems (APLAS 2008), which took place in Bangalore, December 9 - December 11, 2008. The symposium was sponsored by the Asian Association for Foundation of Software (AAFS) and the Indian Institute of S- ence. It was held at the Indian Institute of Science, as part of the institute's centenary celebrations, and was co-located with FSTTCS (Foundations of So- ware Technology and Theoretical Computer Science) 2008, organized by the Indian Association for Research in Computer Science (IARCS). In response to the call for papers, 41 full submissions were received. Each submission was reviewed by at least four Program Committee members with the help of external reviewers. The ProgramCommittee meeting was conducted electronically over a 2-week period. After careful discussion, the Program C- mittee selected 20 papers. I would like to sincerely thank all the members of the APLAS 2008 Program Committee for their excellent job, and all the external reviewers for their invaluable contribution. The submission and review process was managed using the EasyChair system. In addition to the 20 contributed papers, the symposium also featured three invitedtalksbyDinoDistefano(QueenMary, UniversityofLondon, UK), Radha Jagadeesan (DePaul University, USA), and Simon Peyton-Jones (Microsoft - search Cambridge, UK). Many people have helped to promote APLAS as a high-quality forum in Asia to serveprogramminglanguageresearchersworldwide.Following a seriesof well-attendedworkshopsthatwereheldinSingapore(2000), Daejeon(2001), and Shanghai (2002), the ?rst ?ve formal symposiums were held in Beijing (2003), Taipei (2004), Tsukuba (2005), Sydney (2006), and Singapore (2007).

Incremental computation concerns the re-computation of output after a change in the input, whereas algorithms and programs usually derive their output directly from their input. This book investigates the concept of incremental computation and dynamic algorithms in general and provides a variety of new results, especially for computational problems from graph theory: the author presents e.g. efficient incremental algorithms for several shortest-path problems as well as incremental algorithms for the circuit value annotation problem and for various computations in reducible flow graphs.

Modular heap analysis techniques analyze a program by computing summaries for every procedure in the program that describes its effects on an input heap, using pre-computed summaries for the called procedures. In A Framework For Efficient Modular Heap Analysis, the focus is on a family of modular heap analyses that summarize a procedure's heap effects using a context-independent, shape-graph-like summary that is agnostic to the aliasing in the input heap. These analyses are very efficient but their complexity and the absence of a theoretical formalization and correctness proofs makes it hard to produce correct extensions and modifications of these algorithms - whether to improve precision or scalability or to compute more information. This book presents a modular heap analysis framework that generalizes these four analyses. It formalizes this framework as an abstract interpretation and establishes the correctness and termination guarantees. It formalizes the four analyses as instances of the framework. The formalization explains the basic principle behind such modular analyses and simplifies the task of producing extensions and variations of such analyses. It is written with exceptional clarity and is a delightful read for program analysis experts and novices alike.