On the basis for ELF - An Extensible Language Facility

Computer language for data processing and information retrieva

GIER: A Danish computer from 1961 with a role in the modern revolution of astronomy

A Danish computer, GIER, from 1961 played a vital role in the development of a new method for astrometric measurement. This method, photon counting astrometry, ultimately led to two satellites with a significant role in the modern revolution of astronomy. A GIER was installed at the Hamburg Observatory in 1964 where it was used to implement the entirely new method for the measurement of stellar positions by means of a meridian circle, then the fundamental instrument of astrometry. An expedition to Perth in Western Australia with the instrument and the computer was a success. This method was also implemented in space in the first ever astrometric satellite Hipparcos launched by ESA in 1989. The Hipparcos results published in 1997 revolutionized astrometry with an impact in all branches of astronomy from the solar system and stellar structure to cosmic distances and the dynamics of the Milky Way. In turn, the results paved the way for a successor, the one million times more powerful Gaia astrometry satellite launched by ESA in 2013. Preparations for a Gaia successor in twenty years are making progress.Comment: 19 pages,8 figures, Accepted for publication in Nuncius Hamburgensis, Volume 2

Development of an MSC language and compiler, volume 1

Higher order programming language and compiler for advanced computer software system to be used with manned space flights between 1972 and 198

Towards a machine-independent transput section

If the transput section of an ALGOL-68 compiler is to be portable, it must be described in such a way that it is clear which aspects are machine-dependent, and which are not. There should be a clear set of primitives underlying the transput. In this report, a description is proposed which can really be used as an implementation model: the transput is described in pseudo-ALGOL 68, except for the underlying primitives, whose semantics are given in some kind of formalized English. The state of this model is by no means definitive, but may serve as a start for further discussion

A Rational Deconstruction of Landin's SECD Machine with the J Operator

Landin's SECD machine was the first abstract machine for applicative expressions, i.e., functional programs. Landin's J operator was the first control operator for functional languages, and was specified by an extension of the SECD machine. We present a family of evaluation functions corresponding to this extension of the SECD machine, using a series of elementary transformations (transformation into continu-ation-passing style (CPS) and defunctionalization, chiefly) and their left inverses (transformation into direct style and refunctionalization). To this end, we modernize the SECD machine into a bisimilar one that operates in lockstep with the original one but that (1) does not use a data stack and (2) uses the caller-save rather than the callee-save convention for environments. We also identify that the dump component of the SECD machine is managed in a callee-save way. The caller-save counterpart of the modernized SECD machine precisely corresponds to Thielecke's double-barrelled continuations and to Felleisen's encoding of J in terms of call/cc. We then variously characterize the J operator in terms of CPS and in terms of delimited-control operators in the CPS hierarchy. As a byproduct, we also present several reduction semantics for applicative expressions with the J operator, based on Curien's original calculus of explicit substitutions. These reduction semantics mechanically correspond to the modernized versions of the SECD machine and to the best of our knowledge, they provide the first syntactic theories of applicative expressions with the J operator

Early Nordic compilers and autocodes

Abstract. The early development of compilers for high-level program-ming languages, and of so-called autocoding systems, is well documented at the international level but not as regards the Nordic countries. The goal of this paper is to provide a survey of compiler and autocode development in the Nordic countries in the early years, roughly 1953 to 1965, and to relate it to international developments. We also touch on some of the historical societal context

Memoized zipper-based attribute grammars and their higher order extension

Attribute grammars are a powerfull, well-known formalism to implement and reason about programs which, by design, are conveniently modular. In this work we focus on a state of the art zipper-based embedding of classic attribute grammars and higher-order attribute grammars. We improve their execution performance through controlling attribute (re)evaluation by means of memoization techniques. We present the results of our optimizations by comparing their impact in various implementations of different, well-studied, attribute grammars and their Higher-Order extensions. (C) 2018 Elsevier B.V. All rights reserved.- (undefined