scm - Online in the Cloud

PROGRAM:

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.

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