15,338 research outputs found
The C++0x "Concepts" Effort
C++0x is the working title for the revision of the ISO standard of the C++
programming language that was originally planned for release in 2009 but that
was delayed to 2011. The largest language extension in C++0x was "concepts",
that is, a collection of features for constraining template parameters. In
September of 2008, the C++ standards committee voted the concepts extension
into C++0x, but then in July of 2009, the committee voted the concepts
extension back out of C++0x.
This article is my account of the technical challenges and debates within the
"concepts" effort in the years 2003 to 2009. To provide some background, the
article also describes the design space for constrained parametric
polymorphism, or what is colloquially know as constrained generics. While this
article is meant to be generally accessible, the writing is aimed toward
readers with background in functional programming and programming language
theory. This article grew out of a lecture at the Spring School on Generic and
Indexed Programming at the University of Oxford, March 2010
Application-tailored Linear Algebra Algorithms: A search-based Approach
In this paper, we tackle the problem of automatically generating algorithms
for linear algebra operations by taking advantage of problem-specific
knowledge. In most situations, users possess much more information about the
problem at hand than what current libraries and computing environments accept;
evidence shows that if properly exploited, such information leads to
uncommon/unexpected speedups. We introduce a knowledge-aware linear algebra
compiler that allows users to input matrix equations together with properties
about the operands and the problem itself; for instance, they can specify that
the equation is part of a sequence, and how successive instances are related to
one another. The compiler exploits all this information to guide the generation
of algorithms, to limit the size of the search space, and to avoid redundant
computations. We applied the compiler to equations arising as part of
sensitivity and genome studies; the algorithms produced exhibit, respectively,
100- and 1000-fold speedups
Action semantics in retrospect
This paper is a themed account of the action semantics project, which Peter Mosses has led since the 1980s. It explains his motivations for developing action semantics, the inspirations behind its design, and the foundations of action semantics based on unified algebras. It goes on to outline some applications of action semantics to describe real programming languages, and some efforts to implement programming languages using action semantics directed compiler generation. It concludes by outlining more recent developments and reflecting on the success of the action semantics project
Canonical Abstract Syntax Trees
This paper presents Gom, a language for describing abstract syntax trees and
generating a Java implementation for those trees. Gom includes features
allowing the user to specify and modify the interface of the data structure.
These features provide in particular the capability to maintain the internal
representation of data in canonical form with respect to a rewrite system. This
explicitly guarantees that the client program only manipulates normal forms for
this rewrite system, a feature which is only implicitly used in many
implementations
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