Scheme 48 is an implementation of Scheme written by Richard Kelsey and
Jonathan Rees. It is based on a byte-code interpreter and is designed
to be used as a testbed for experiments in implementation techniques
and as an expository tool. It comes with a module system, an extensive
set of libraries, an interactive command-line-based development
environment and a manual in various formats. Scheme 48 runs on most
Unix/Linux systems, as well as Windows NT, 2000, XP, and Vista, and is
fully R5RS-conformant.
Scheme 48 is available (under a very liberal license) from
http://www.s48.org/
Scheme 48 1.8 represents a significant internal reorganization of the
OS integration over 1.7. In particular, 64-bit architectures are now
finally sup****ted, and a few system components are now dynamically
loaded rather than built as a static part of the VM. Other than that,
there are few user-visible changes or new features.
Enjoy!
The Scheme 48 maintainers
Additions:
An experimental framework for asynchronous events from
external code was added. It's now used for asynchronous
host-name lookups on systems with pthreads.
Sup****t for 64-bit architectures was added (thanks to
Taylor Campbell, Marcus Crestani, and David Frese)
The installation now includes an (experimental)
"scheme48-config" script that re****ts C compiler and
linker and associated flags that may be used for compiling
dynamic externals.
Changes:
The layout of the installed system now conforms to FHS.
The old dynamic-loading code was removed; correspondingly,
the -o flag for scheme48vm was removed.
The filename translations apply to dynamic externals as
well.
On Unix, the central event loop uses poll() instead of select()
on
systems that have it (thanks to Marcus Crestani)
The external code for the POSIX libraries and SRFI 27 was
moved to dynamically-loaded externals. (Cygwin sup****t
for this thanks to Harald Glab-Plhak)
Bug fixes:
A bug in the division simplifier of the PreScheme compiler
was fixed.
The PreScheme compiler can now emit code for unsigned longs.
The implementations of SRFI 19 and SRFI 42 now include the
latest fixes from the reference implementations.
A race condition in the implementation of queues was fixed.
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