http://people.csail.mit.edu/jaffer/SCM
	The SCM Implementation of Scheme
	Current Version Released Terms 5f2 2015-01-16 LGPL

SCM includes Hobbit, the Scheme-to-C compiler originally written by Tanel Tammet. Hobbit generates C files whose binaries can be dynamically or statically linked with a SCM executable. SCM includes linkable modules for sequence-comparison, arrays, records, and byte-number conversions; and modules for POSIX system calls and network-sockets, readline, ncurses, and Xlib.

On some platforms SCM supports unexec (developed for Emacs and bash), which dumps a executable image from a running SCM. This results in very low latency (12.ms) startup for SCM.

SCM requires the SLIB Scheme Library. Both SCM and SLIB are GNU packages.

News

scm-5f2 improves the speed of floating-point I/O. Details at http://cvs.savannah.gnu.org/viewvc/*checkout*/scm/scm/ChangeLog.

• scl.c (int2dbl, pmantexp2dbl): Recycle temporary bignums.
  (pmantexp2dbl): Handle exponents smaller than -324.
  (pmantexp2dbl): Optimized. Added bigrecy(quo).
  (pmantexp2dbl): call int2dbl() instead of num2dbl().
  (pdbl2str, pmantexp2dbl): Use powers-of-5 table instead of powers-of-10.
  (strrecy, pdbl2str): Recycle temporary string used in number->string conversion.
  (scm_intexpt): Call bigrecy only when #ifdef BIGDIG.
  (bigrecy): Added procedure to recycle bignums.
  (int2dbl, scm_intexpt, divide, difference, big2str)
  (pdbl2str, mantexp2dbl, pmantexp2dbl, int2dbl): Recycle temporary bignums.
  (pdbl2str): Replaced call to int2dbl() with scm_intlength().
• r4rstest.scm (test-bignum): Added tests for GCD and LCM.
• sys.c (sysptob): Added sysflush (for sys_errp). Fixed exit when verbose > 3.
• subr.c (scm_bitwise_bit_count, scm_logcount, scm_intlength) (big2inum): Recycle temporary bignums.
• scm.c (process_signals): Reenabled lfflush(sys_errp).
• scm.texi: TeXinfo-5 now disallows text between @defunx lines.
  (Internal State): Added "(gc #t)".

From: Marc Espie

• time.c: OpenBSD is phasing out old interfaces such as ftime and the timeb data structure. This change should allow things to work in a saner way on any system that uses gettimeofday().

Quick Start

x86 MS-Windows

Obtain slib-3b5-1.exe (1.1.MB) and run.
Obtain scm-5f2-1.exe (475.kB) and run.
Release Notes:

• The Windows installers were packaged by the NSIS (Nullsoft Scriptable Install System).
• The SCM executable for MS-Windows was compiled by MinGw version 5.1.6
• SCM.EXE supports WB B-Tree Databases with SCM.

i686 GNU/Linux with RPM

Obtain slib-3b5-1.noarch.rpm (760.kB) and scm-5f2-1.i686.rpm (960.kB) and install.

x86_64 GNU/Linux with RPM

Obtain slib-3b5-1.noarch.rpm (760.kB) and scm-5f2-1.x86_64.rpm (1.2.MB) and install.

Build From Source

• Obtain the last release: slib-3b5.zip (1.1.MB) and scm-5f2.zip (920.kB)
  or the current development snapshot: slib.zip (1.1.MB) and scm.zip (930.kB).
• Follow the instructions in Installing SCM, chapter 2 of the SCM manual.

Documentation

• Online SCM Manual; or scm.pdf
• Online Xlibscm Manual; or Xlibscm.pdf
• Online Hobbit Compiler Manual; or hobbit.pdf
• Online SLIB Manual; or slib.pdf
• Online Revised⁵ Report on the Algorithmic Language Scheme; or r5rs.pdf
• HTML labyrinth of the build relational database generated by the command:
  scm -r'db->html' -rbuild -e'(db->html-directory build "build")'

SCM Development

• Savannah: CVS Repository scm/scm
• Development Snapshot scm.zip (830.kB)
• SCM discussion mailing list

Related Sites and Software

• SLIB Scheme Library
• WB B-Tree Databases for SCM.
• Scheme - Dai Inukai gives excellent help and information about compiling, installing, and using SCM and other implementations on a variety of platforms.
• SCM for Macintosh (original site)
• Galapagos interactive multithreaded Scheme interpreter with turtle graphics for Windows 95.
• SCM for PocketPC running PocketConsole
• Guile Universal Scripting Language
• SCM interface to MYSQL
• The #! program implements "#!" (POSIX) shell-scripts for MS-DOS batch files.
  Fetch http://groups.csail.mit.edu/mac/ftpdir/scm/sharpbang.zip or http://groups.csail.mit.edu/mac/ftpdir/scm/#!.zip and unzip into a %PATH% directory.

Miscellany

• About SCM Interpreter Speed
• SCM Interpreter Latency
• Using SCM in Engineering
• FTP Links to SCM and related software from this site and mirrors.
• htmls.zip, a collection of these html documentation files (600.kB)