1,598 research outputs found
On the Portability of Prolog Applications
The non-portability of Prolog programs is widely considered one of the main problems facing Prolog programmers. Although since 1995, the core of the language is covered by the ISO standard 13211-1, this standard has not been sufficient to support large Prolog applications. As an approach to address this problem, since 2007, YAP and SWI-Prolog have established a basic compatibility framework. The aim of the framework is running the same code on Edinburgh-based Prolog systems rather than having to migrate an application. This article describes the implementation and evaluates this framework by studying how it can be used on a number of libraries and an important application. © 2011 Springer-Verlag
Portability of Prolog programs: theory and case-studies
(Non-)portability of Prolog programs is widely considered as an important
factor in the lack of acceptance of the language. Since 1995, the core of the
language is covered by the ISO standard 13211-1. Since 2007, YAP and SWI-Prolog
have established a basic compatibility framework. This article describes and
evaluates this framework. The aim of the framework is running the same code on
both systems rather than migrating an application. We show that today, the
portability within the family of Edinburgh/Quintus derived Prolog
implementations is good enough to allow for maintaining portable real-world
applications.Comment: Online proceedings of the Joint Workshop on Implementation of
Constraint Logic Programming Systems and Logic-based Methods in Programming
Environments (CICLOPS-WLPE 2010), Edinburgh, Scotland, U.K., July 15, 201
Lock-free atom garbage collection for multithreaded Prolog
The runtime system of dynamic languages such as Prolog or Lisp and their
derivatives contain a symbol table, in Prolog often called the atom table. A
simple dynamically resizing hash-table used to be an adequate way to implement
this table. As Prolog becomes fashionable for 24x7 server processes we need to
deal with atom garbage collection and concurrent access to the atom table.
Classical lock-based implementations to ensure consistency of the atom table
scale poorly and a stop-the-world approach to implement atom garbage collection
quickly becomes a bottle-neck, making Prolog unsuitable for soft real-time
applications. In this article we describe a novel implementation for the atom
table using lock-free techniques where the atom-table remains accessible even
during atom garbage collection. Relying only on CAS (Compare And Swap) and not
on external libraries, the implementation is straightforward and portable.
Under consideration for acceptance in TPLP.Comment: Paper presented at the 32nd International Conference on Logic
Programming (ICLP 2016), New York City, USA, 16-21 October 2016, 14 pages,
LaTeX, 4 PDF figure
Customisable Handling of Java References in Prolog Programs
Integration techniques for combining programs written in distinct language
paradigms facilitate the implementation of specialised modules in the best
language for their task. In the case of Java-Prolog integration, a known
problem is the proper representation of references to Java objects on the
Prolog side. To solve it adequately, multiple dimensions should be considered,
including reference representation, opacity of the representation, identity
preservation, reference life span, and scope of the inter-language conversion
policies. This paper presents an approach that addresses all these dimensions,
generalising and building on existing representation patterns of foreign
references in Prolog, and taking inspiration from similar inter-language
representation techniques found in other domains. Our approach maximises
portability by making few assumptions about the Prolog engine interacting with
Java (e.g., embedded or executed as an external process). We validate our work
by extending JPC, an open-source integration library, with features supporting
our approach. Our JPC library is currently compatible with three different open
source Prolog engines (SWI, YAP} and XSB) by means of drivers. To appear in
Theory and Practice of Logic Programming (TPLP).Comment: 10 pages, 2 figure
SICStus MT - A Multithreaded Execution Environment for SICStus Prolog
The development of intelligent software agents and other
complex applications which continuously interact with their
environments has been one of the reasons why explicit concurrency has
become a necessity in a modern Prolog system today. Such applications
need to perform several tasks which may be very different with respect
to how they are implemented in Prolog. Performing these tasks
simultaneously is very tedious without language support.
This paper describes the design, implementation and evaluation of a
prototype multithreaded execution environment for SICStus Prolog. The
threads are dynamically managed using a small and compact set of
Prolog primitives implemented in a portable way, requiring almost no
support from the underlying operating system
Generic Traces and Constraints, GenTra4CP revisited
The generic trace format GenTra4CP has been defined in 2004 with the goal of
becoming a standard trace format for the observation of constraint solvers over
finite domains. It has not been used since. This paper defines the concept of
generic trace formally, based on simple transformations of traces. It then
analyzes, and occasionally corrects, shortcomings of the proposed initial
format and shows the interest that a generic tracer may bring to develop
portable applications or to standardization efforts, in particular in the field
of constraints
- …