NAME¶
scm - a Scheme Language Interpreter
SYNOPSIS¶
scm [-a
kbytes ] [-muvqib] [--version] [--help]
[[-]-no-init-file] [--no-symbol-case-fold]
[-p
int ] [-r
feature ] [-h
feature ]
[-d
filename ] [-f
filename ] [-l
filename ]
[-c
expression ] [-e
expression ] [-o
dumpname ]
[-- | - | -s] [
filename ] [
arguments ... ]
DESCRIPTION¶
Scm is a Scheme interpreter.
Upon startup
scm loads the file specified by by the environment variable
SCM_INIT_PATH or by the parameter IMPLINIT in the makefile (or scmfig.h) if
SCM_INIT_PATH is not defined. The makefiles attempt to set IMPLINIT to
"Init.scm" in the source directory.
Unless the option
-no-init-file or
--no-init-file occurs in the
command line or if
scm is being invoked as a script,
"Init.scm" checks to see if there is file "ScmInit.scm" in
the path specified by the environment variable HOME (or in the current
directory if HOME is undefined). If it finds such a file, then it is loaded.
"Init.scm" then looks for command input from one of three sources:
From an option on the command line, from a file named on the command line, or
from standard input.
OPTIONS¶
The options are processed in the order specified on the command line.
- -akbytes
- specifies that scm should allocate an initial heapsize of
kbytes. This option, if present, must be the first on the command
line.
- --no-init-file
- Inhibits the loading of "ScmInit.scm" as described above.
- --no-symbol-case-fold
- Symbol (and identifier) names are case-sensitive.
- -eexpression
- -cexpression
- specifies that the scheme expression expression is to be evaluated.
These options are inspired by perl and sh respectively. On
Amiga systems the entire option and argument need to be enclosed in
quotes. For instance "-e(newline)".
- -rfeature
- requires feature. This will load a file from SLIB if that
feature is not already supported. If feature is 2, 3, 4, or
5 scm will require the features necessary to support R2RS, R3RS,
R4RS, or R5RS, respectively.
- -hfeature
- provides feature.
- -lfilename
- -ffilename
- loads filename. Scm will load the first (unoptioned) file
named on the command line if no -c, -e, -f, -l, or -s option precedes
it.
- -dfilename
- opens (read-only) the extended relational database filename. If
filename contains initialization code, it will be run when the
database is opened.
- -odumpname
- saves the current SCM session as the executable program dumpname.
This option works only in SCM builds supporting dump.
If options appear on the command line after -o dumpname, then the
saved session will continue with processing those options when it is
invoked. Otherwise the (new) command line is processed as usual when the
saved image is invoked.
- -plevel
- sets the prolixity (verboseness) to level. This is the same as the
scm command (verbose level ).
- -v
- (verbose mode) specifies that scm will print prompts, evaluation
times, notice of loading files, and garbage collection statistics. This is
the same as -p3.
- -q
- (quiet mode) specifies that scm will print no extra information.
This is the same as -p0.
- -m
- specifies that subsequent loads, evaluations, and user interactions will
be with R4RS macro capability. To use a specific R4RS macro implementation
from SLIB (instead of SLIB's default) put -r macropackage before
-m on the command line.
- -u
- specifies that subsequent loads, evaluations, and user interactions will
be without R4RS macro capability. R4RS macro capability can be restored by
a subsequent -m on the command line or from Scheme code.
- -i
- specifies that scm should run interactively. That means that
scm will not terminate until the (quit) or (exit)
command is given, even if there are errors. It also sets the prolixity
level to 2 if it is less than 2. This will print prompts, evaluation
times, and notice of loading files. The prolixity level can be set by
subsequent options. If scm is started from a tty, it will assume
that it should be interactive unless given a subsequent -b
option.
- -b
- specifies that scm should run non-interactively. That means that
scm will terminate after processing the command line or if there
are errors.
- -s
- specifies, by analogy with sh, that further options are to be
treated as program arguments.
- -
- -- specifies that there are no more options on the command
line.
ENVIRONMENT VARIABLES¶
- SCM_INIT_PATH
- is the pathname where scm will look for its initialization code.
The default is the file "Init.scm" in the source directory.
- SCHEME_LIBRARY_PATH
- is the SLIB Scheme library directory.
- HOME
- is the directory where "Init.scm" will look for the user
initialization file "ScmInit.scm".
SCHEME VARIABLES¶
- *argv*
- contains the list of arguments to the program. *argv* can change
during argument processing. This list is suitable for use as an argument
to SLIB getopt.
- *R4RS-macro*
- controls whether loading and interaction support R4RS macros. Define this
in "ScmInit.scm" or files specified on the command line. This
can be overridden by subsequent -m and -u options.
- *interactive*
- controls interactivity as explained for the -i and -b options. Define this
in "ScmInit.scm" or files specified on the command line. This
can be overridden by subsequent -i and -b options.
EXAMPLES¶
- % scm foo.scm arg1 arg2 arg3
- Load and execute the contents of foo.scm. Parameters arg1 arg2 and arg3
are stored in the global list *argv*.
- % scm -f foo.scm arg1 arg2 arg3
-
The same.
- % scm -s foo.scm arg1 arg2
-
Set *argv* to ("foo.scm" "arg1" "arg2") and
enter interactive session.
- % scm -e '(display (list-ref *argv* *optind*))' bar
-
Print ``bar''
- % scm -rpretty-print -r format -i
-
Load pretty-print and format and enter interactive mode.
- % scm -r5
-
Load dynamic-wind, values, and R4RS macros and enter interactive (with
macros) mode.
- % scm -r5 -r4
-
Like above but rev4-optional-procedures are also loaded.
FEATURES¶
Runs under Amiga, Atari-ST, MacOS, MS-DOS, OS/2, NOS/VE, Unicos, VMS, Unix and
similar systems. Support for ASCII and EBCDIC character sets.
Conforms to Revised^5 Report on the Algorithmic Language Scheme and the IEEE
P1178 specification.
Support for SICP, R2RS, R3RS, and R4RS scheme code.
Many Common Lisp functions: logand, logor, logxor, lognot, ash, logcount,
integer-length, bit-extract, defmacro, macroexpand, macroexpand1, gentemp,
defvar, force-output, software-type, get-decoded-time, get-internal-run-time,
get-internal-real-time, delete-file, rename-file, copy-tree, acons, and eval.
Char-code-limit, most-positive-fixnum, most-negative-fixnum, and
internal-time-units-per-second constants. *Features* and *load-pathname*
variables.
Arrays and bit-vectors. String ports and software emulation ports. I/O
extensions providing most of ANSI C and POSIX.1 facilities.
User definable responses to interrupts and errors, Process-synchronization
primitives, String regular expression matching, and the CURSES screen
management package.
Available add-on packages including an interactive debugger, database, X-window
graphics, BGI graphics, Motif, and Open-Windows packages.
A compiler (HOBBIT, available separately) and dynamic linking of compiled
modules.
Setable levels of monitoring and timing information printed interactively (the
`verbose' function). Restart, quit, and exec.
FILES¶
- scm.texi
-
Texinfo documentation of scm enhancements, internal representations,
and how to extend or include scm in other programs.
AUTHORS¶
Aubrey Jaffer (jaffer @ alum.mit.edu)
Radey Shouman (shouman @ ne.mediaone.net)
BUGS¶
SEE ALSO¶
The SCM home-page:
http://swissnet.ai.mit.edu/~jaffer/SCM.html
The Scheme specifications for details on specific procedures
(
http://swissnet.ai.mit.edu/ftpdir/scheme-reports/) or
IEEE Std 1178-1990,
IEEE Standard for the Scheme Programming Language,
Institute of Electrical and Electronic Engineers, Inc.,
New York, NY, 1991
Brian Harvey and Matthew Wright
Simply Scheme: Introducing Computer Science_
MIT Press, 1994 ISBN 0-262-08226-8
R. Kent Dybvig, The Scheme Programming Language,
Prentice-Hall Inc, Englewood Cliffs, New Jersey 07632, USA
H. Abelson, G. J. Sussman, and J. Sussman,
Structure and Interpretation of Computer Programs,
The MIT Press, Cambridge, Massachusetts, USA