87 lines
4.1 KiB
Text
87 lines
4.1 KiB
Text
|
% Copyright 2005-2017 Cisco Systems, Inc.
|
||
|
|
%
|
||
|
|
% Licensed under the Apache License, Version 2.0 (the "License");
|
||
|
|
% you may not use this file except in compliance with the License.
|
||
|
|
% You may obtain a copy of the License at
|
||
|
|
%
|
||
|
|
% http://www.apache.org/licenses/LICENSE-2.0
|
||
|
|
%
|
||
|
|
% Unless required by applicable law or agreed to in writing, software
|
||
|
|
% distributed under the License is distributed on an "AS IS" BASIS,
|
||
|
|
% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
||
|
|
% See the License for the specific language governing permissions and
|
||
|
|
% limitations under the License.
|
||
|
|
\chapter{Preface}
|
||
|
|
|
||
|
|
{\ChezScheme} is both a general-purpose programming language and
|
||
|
|
an implementation of that language, with supporting tools and
|
||
|
|
documentation.
|
||
|
|
As a superset of the language described in the Revised$^6$ Report
|
||
|
|
on Scheme (R6RS), {\ChezScheme} supports all standard features of
|
||
|
|
Scheme, including first-class procedures, proper treatment of tail
|
||
|
|
calls, continuations, user-defined records, libraries, exceptions,
|
||
|
|
and hygienic macro expansion.
|
||
|
|
{\ChezScheme} supports numerous non-R6RS features.
|
||
|
|
A few of these are local and top-level modules,
|
||
|
|
local import, foreign datatypes and procedures, nonblocking I/O,
|
||
|
|
an interactive top-level, compile-time values and properties,
|
||
|
|
pretty-printing, and formatted output.
|
||
|
|
|
||
|
|
The implementation includes a compiler that generates native code
|
||
|
|
for each processor upon which it runs along with a run-time system
|
||
|
|
that provides automatic storage management, foreign-language
|
||
|
|
interfaces, source-level debugging, profiling support, and an
|
||
|
|
extensive run-time library.
|
||
|
|
|
||
|
|
The threaded versions of {\ChezScheme} support native threads, allowing
|
||
|
|
Scheme programs to take advantage of multiprocessor or multiple-core
|
||
|
|
systems.
|
||
|
|
Nonthreaded versions are also available and are faster for
|
||
|
|
single-threaded applications.
|
||
|
|
Both 32-bit and 64-bit versions are available for some platforms.
|
||
|
|
The 64-bit versions support larger heaps, while the 32-bit versions
|
||
|
|
are faster for some applications.
|
||
|
|
|
||
|
|
{\ChezScheme}'s interactive programming system includes an expression
|
||
|
|
editor that, like many shells, supports command-line editing, a history
|
||
|
|
mechanism, and command completion.
|
||
|
|
Unlike most shells that support command-line editing, the expression
|
||
|
|
editor properly supports multiline expressions.
|
||
|
|
|
||
|
|
{\ChezScheme} is intended to be as reliable and efficient as possible,
|
||
|
|
with reliability taking precedence over efficiency if necessary.
|
||
|
|
Reliability means behaving as designed and documented.
|
||
|
|
While a {\ChezScheme} program can always fail to work properly
|
||
|
|
because of a bug in the program, it should never fail because of a
|
||
|
|
bug in the {\ChezScheme} implementation.
|
||
|
|
Efficiency means performing at a high level, consuming minimal CPU
|
||
|
|
time and memory.
|
||
|
|
Performance should be balanced across features, across run time and
|
||
|
|
compile time, and across programs and data of different sizes.
|
||
|
|
These principles guide {\ChezScheme} language and tool design as
|
||
|
|
well as choice of implementation technique; for example, a language
|
||
|
|
feature or debugging hook might not exist in {\ChezScheme} because
|
||
|
|
its presence would reduce reliability, efficiency, or both.
|
||
|
|
|
||
|
|
The compiler has been rewritten for Version~9 and generates
|
||
|
|
substantially faster code than the earlier compiler at the cost of
|
||
|
|
greater compile time.
|
||
|
|
This is the primary difference between Versions~8 and~9.
|
||
|
|
|
||
|
|
This book (CSUG) is a companion to \emph{The Scheme Programming
|
||
|
|
Language, 4th Edition} (TSPL4).
|
||
|
|
TSPL4 serves as an introduction to and reference for R6RS, while
|
||
|
|
CSUG describes {\ChezScheme} features and tools that are not part
|
||
|
|
of R6RS.
|
||
|
|
For the reader's convenience, the summary of forms and index at the back
|
||
|
|
of this book contain entries from both books, with each entry from TSPL4
|
||
|
|
marked with a ``t'' in front of its page number.
|
||
|
|
In the online version, the page numbers given in the summary of forms and
|
||
|
|
index double as direct links into one of the documents or the other.
|
||
|
|
|
||
|
|
Additional documentation for {\ChezScheme} includes release notes, a
|
||
|
|
manual page, and a number of published papers and articles that describe
|
||
|
|
various aspects of the system's design and implementation.
|
||
|
|
|
||
|
|
Thank you for using {\ChezScheme}.
|