84 lines
2.7 KiB
TeX
84 lines
2.7 KiB
TeX
\documentstyle[11pt]{article}
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%Defaults from art10.sty:
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%\textwidth 345pt \columnsep 10pt \columnseprule 0pt
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\advance\textwidth by 0.5in
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\begin{document}
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\vspace*{-0.3in}
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\begin{center}
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{\large\bf Scheme 48} \\
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\vspace{1ex}
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Richard Kelsey ({\tt kelsey@corwin.ccs.northeastern.edu}) \\
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Jonathan Rees ({\tt jar@cs.cornell.edu}) \\
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June 1992
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\end{center}
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\vspace{1ex}
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Scheme 48 is an implementation of the Scheme programming language based
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on a virtual machine architecture. The following is an overview of
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the project.
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\paragraph{Goals}
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\begin{itemize}
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\setlength{\itemsep}{0pt}
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\item Straightforward, minimal implementation.
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\item Flexible experimental apparatus for research in programming
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language design and implementation.
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\item Easy to make changes to internal data representations, memory
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management, and compilation strategy.
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\item High reliability.
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\item Fast and complete enough to be a good
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development environment for Scheme programs.
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\end{itemize}
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\paragraph{Virtual machine}
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The virtual machine executes a simple byte-code instruction set
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similar to the target of the Scheme 311 compiler [Clinger, LFP 1984].
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The interpreter for the virtual instruction set is itself written in
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PreScheme, a systems programming dialect of Scheme. A PreScheme
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compiler applies intensive source-to-source rewrites to the
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interpreter source code and emits low-level C code. When the output
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is then compiled by an optimizing C compiler such as gcc, the result
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is a very efficient and portable emulator.
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\paragraph{Run-time system}
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The virtual machine is initialized from a specified memory image
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containing byte-compiled Scheme code and data. Images (including
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small stand-alone applications) are built either by a linker or by
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writing out the state of an executing program. A standard memory
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image contains a Scheme run-time library ({\tt append}, {\tt read},
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{\tt write}, etc.), a compiler from Scheme to the virtual instruction
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set, and a command processor and debugger. In this way Scheme 48 can
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be configured to look like a conventional Lisp interpreter.
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In addition to the Scheme run-time library and development
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environment, library software includes support for multitasking,
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modules (packages), hygienic macros (as described in the Revised$^4$
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Scheme report), records, and exception handling.
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\paragraph{Applications}
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The Scheme 48 system is being used at several sites for research in
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memory management, embedded systems, multiprocessing, and computer
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system verification. Scheme 48 was chosen as the platform for these
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projects because of its internal tractability and flexibility.
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\end{document}
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