ARS plus plus
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- The title of this article is incorrect because of technical limitations. The correct title is ARS++.
History
ARS++ has been developed in 2002 for the book Undiluted Programming (a description of the book is available on page [1] (http://www.lambda-bound.de/book/engl/index.html)) to demonstrate ARS based programming in a real world context. ARS++ is used in the book to implement an A++ interpreter and an XML Database System. Even the implementation of ARS++ in C was used to demonstrate ARS based programming.
Principally the programming language Scheme would have been perfectly alright to be used for these demonstration programs if Scheme would include primitives supporting network programming, database programming plus a few others required in this context.
The definition of the programming language Scheme does not include those primitives however, leaving this issue up to the implementors of the language. The consequence is that there exist many Scheme implementations, almost none of them covering all areas essential for real application programs.
This is the historical background that gave birth to the development of ARS++.
A few weeks ago the author of the referenced book discovered a Scheme implementation that would have been very well suited to serve as a language for developing the case studies for 'Undiluted Programming'. This Scheme implementation is called Gauche and is available for download in the internet on the following page [2] (http://www.shiro.dreamhost.com/scheme/gauche/).
ARS++ explained by its name
The name ARS++, being an acronym for ARS + Scheme + Extensions, indicates that ARS++ has a lot to do with Scheme but that it is not equivalent to Scheme.
- The first part of the name refers to the core of the language, which is nothing else but A++, i.e. Abstraction + Reference + Synthesis.
The structure of A++ however is different from the structure of Scheme, which can be verified by comparing the definition of Scheme in R5RS with the definition of A++ on page [3] (http://www.lambda-bound.de/book/lambdacalc/node41.html) and the following. - The second part in the name of ARS++ stands for the primitive functions that are imported from Scheme, giving ARS++ almost the same functionality as Scheme.
Primitive functions are those, that are not and cannot be defined as lambda abstractions because they are representing a functionality that can only be provided by the underlying operating system or the hardware. - The third part of the name refers to primitive functions that are not defined in R5RS (the official definition of the programming language Scheme) but are nevertheless important for real world programming like functions allowing to work with regular expressions, with TCP/IP networks, with embedded databases (e.g. Berkeley DB, GNU database manager) and a few that provide an interface with the operating system.
From a practical point of view a Scheme implementation that includes support for regular expressions, databases, sockets and also provides an interface to the operating system can be called an ARS++ language (ignoring the difference in the nucleus which practically is only noticed by the programmer when using the special form define).