Abstract State Machines 1988-1998: Commented ASM Bibliography

An annotated bibliography of papers which deal with or use Abstract State Machines (ASMs), as of January 1998.Comment: Also maintained as a BibTeX file at http://www.eecs.umich.edu/gasm

Modeling web applications infrastructure with ASMs

We describe via Abstract State Machines the major ingredients of contemporary web applications: a web browser running JavaScript programs and a web server dispatching requests to one of several modules, each one representing a class of established web application frameworks. The web browser model comes in four levels, namely transport, stream, context and browser level, and is focussed on the interaction with possibly multiple servers (which requires a concurrent computation model) and on script execution (which requires a dynamic assignment of agents to programs). The server model is focussed on the Request–Reply pattern, and specifies a delegation strategy where the handling of a request is entrusted to a module. We show how several major frameworks for web applications can be described as progressive refinements of a number of basic modules. Three modules are further detailed: static file transfer, CGI and generic scripting modules

ABZ2008 Conference - Short Papers

Short papers of the ABZ 2008 Conference September 16-18, 2008 BCS London Offices, Covent Garden, London, UK Full published proceedings in Springer LNCS Vol. 5238: http://www.springer.com/computer/programming/book/978-3-540-87602-

A system and method for mediating within a network

Request Number at European Patent Office: EP20050008517 Publication Number of European Patent Office: EP1715653 Year of presentation: 4/19/2005 Requestor: SAP AG (Germany) Granted 2008 Also US Patent: Application No: 11/405363 Publication No: 20060259605 Application Date: 2006-04-17 Publication Date: 2006-11-1

A formal specification of the semantics of ECMAScript

Web applications (i.e., applications whose interface is presented to the user via a web browser, whose state is split between a server and a client, and where the only interaction between server and client is through the HTTP protocol) are become more and more widespread, and integrated in most users' everyday work habits. The glue linking the desperate technologies involved, from dynamic HTML to XML RPC, is the Javascript language. Yet, no formal definition of its semantics exists, which in turn makes it impossible to formally prove correctness, liveness and security properties of Web applications. As a first step towards improving this situation, we provide a formal semantics for ECMAScript (standard ECMA-262), by means of an Abstract State Machines (ASMs) specification. We follow the path established by other specification efforts for similar languages (e.g. Java and C#), but in addition we establish a formal trace between parts of our specification and the ECMA standard, thus facilitating the proof of correctness of the specification. More specifically, we define the dynamic semantics of ECMAScript by providing (in terms of ASMs) an interpreter which executes ECMAScript programs. We use an algebra to represent the state of the ECMAScript program, the state of the ECMAScript interpreter, and the state of the host environment (typically, the browser). We assume the necessary syntactic information (namely, the annotated Abstract Syntax Tree (AST) of the given program) to be available. Using ASM we detail a visit of the AST, whose effect is to simulate the execution of the program. In the ECMA standard the behavior of ECMAScript constructs is operationally described using so-called abstract operations (AO), coming as numbered lists of steps. Therefore our interpreter is composed out of two submachines: ECMA-Script and ECMA-AO interpreters. The former invokes the ECMA-AO one to evaluate nodes, simulating AOs used in ECMA standard to describe the production's semantics. We organize the ECMA-AO interpreter rules in such a way that each rule application corresponds to an AO instruction in the ECMA standard. This helps to check the correctness of the ASM model wrt the ECMA standard as well as the correctness of implementations wrt ASM model. Therefore, the state of our interpreter can be mapped via abstraction/refinement functions onto the concrete state of any comformant implementation