A Monad for Basic Java Semantics

This paper describes the role of a computational monad in the denotational semantics of sequential Java and investigates some of its properties. This denotational semantics is an abstraction of the one used for the verication of (sequential) Java programs using proof tools, see [11,15]

Safely Composable Type-Specific Languages

Abstract. Programming languages often include specialized syntax for com-mon datatypes (e.g. lists) and some also build in support for specific special-ized datatypes (e.g. regular expressions), but user-defined types must use general-purpose syntax. Frustration with this causes developers to use strings, rather than structured data, with alarming frequency, leading to correctness, performance, security, and usability issues. Allowing library providers to modularly extend a language with new syntax could help address these issues. Unfortunately, prior mechanisms either limit expressiveness or are not safely composable: individ-ually unambiguous extensions can still cause ambiguities when used together. We introduce type-specific languages (TSLs): logic associated with a type that determines how the bodies of generic literals, able to contain arbitrary syntax, are parsed and elaborated, hygienically. The TSL for a type is invoked only when a literal appears where a term of that type is expected, guaranteeing non-interference. We give evidence supporting the applicability of this approach and formally specify it with a bidirectionally typed elaboration semantics for the Wyvern programming language

Compilation of Generic Regular Path Expressions Using C++ Class Templates

Various techniques for the navigation and matching of data structures using path expressions have been the subject of extensive investigations. No matter whether such techniques are based on type information, indexing, automata, it is desirable to synthesize implementations automatically, starting from a high-level description of the path expressions to be traversed. In this paper we present a library of C++ templates for the representation of regular path expressions and their compilation into efficient backtracking algorithms. The resulting code can be used to implement visitors, pattern matchers, node collectors on regular paths over possibly heterogeneous, linked data structures. The point of the paper is on the path compilation technique, which was inspired by a continuation-passing, functional semantics of the path expressions. We rely on some peculiar aspects of C++ templates to create a compilation framework that closely follows the given semantics