SCM

This manual is for SCM (version 5e5, February 2008), an implementation of the algorithmic language Scheme.

Copyright © 1990-2007 Free Software Foundation, Inc.

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled “GNU Free Documentation License.”

1. Overview

SCM is a portable Scheme implementation written in C. SCM provides a machine independent platform for [JACAL], a symbolic algebra system. SCM supports and requires the SLIB Scheme library. SCM, SLIB, and JACAL are GNU projects.

1.1 Features

• Conforms to Revised^5 Report on the Algorithmic Language Scheme [R5RS] and the [IEEE] P1178 specification.
• Support for [SICP], [R2RS], [R3RS], and [R5RS] scheme code.
• Runs under Amiga, Atari-ST, MacOS, MS-DOS, OS/2, NOS/VE, Unicos, VMS, Unix and similar systems. Supports ASCII and EBCDIC character sets.
• Is fully documented in TeXinfo form, allowing documentation to be generated in info, TeX, html, nroff, and troff formats.
• Supports inexact real and complex numbers, 30 bit immediate integers and large precision integers.
• 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. slib:features and *load-pathname* variables.
• Arrays and bit-vectors. String ports and software emulation ports. I/O extensions providing ANSI C and POSIX.1 facilities.
• Interfaces to standard libraries including REGEX 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.
• The Hobbit compiler and dynamic linking of compiled modules.
• User definable responses to interrupts and errors, Process-syncronization primitives. Setable levels of monitoring and timing information printed interactively (the verbose function). Restart, quit, and exec.

1.2 Authors

Aubrey Jaffer (agj @ alum.mit.edu)

Most of SCM.

Radey Shouman

Arrays, gsubrs, compiled closures, records, Ecache, syntax-rules macros, and safeports.

Jerry D. Hedden

Real and Complex functions. Fast mixed type arithmetics.

Hugh Secker-Walker

Syntax checking and memoization of special forms by evaluator. Storage allocation strategy and parameters.

George Carrette

Siod, written by George Carrette, was the starting point for SCM. The major innovations taken from Siod are the evaluator’s use of the C-stack and being able to garbage collect off the C-stack (see section Garbage Collection).

There are many other contributors to SCM. They are acknowledged in the file ‘ChangeLog’, a log of changes that have been made to scm.

1.3 Copyright

Authors have assigned their SCM copyrights to:

Free Software Foundation, Inc.

59 Temple Place, Suite 330, Boston, MA 02111, USA

1.3.1 The SCM License

This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with this program. If not, see http://www.gnu.org/licenses/.

1.3.2 SIOD copyright

COPYRIGHT © 1989 BY

PARADIGM ASSOCIATES INCORPORATED, CAMBRIDGE, MASSACHUSETTS.

ALL RIGHTS RESERVED

Permission to use, copy, modify, distribute and sell this software and its documentation for any purpose and without fee is hereby granted, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation, and that the name of Paradigm Associates Inc not be used in advertising or publicity pertaining to distribution of the software without specific, written prior permission.

PARADIGM DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL PARADIGM BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

gjc@paradigm.com

Phone: 617-492-6079

Paradigm Associates Inc 29 Putnam Ave, Suite 6 Cambridge, MA 02138

1.3.3 GNU Free Documentation License

Version 1.2, November 2002

Copyright © 2000,2001,2002 Free Software Foundation, Inc.
51 Franklin St, Fifth Floor, Boston, MA  02110-1301, USA

Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.

1. PREAMBLE

   The purpose of this License is to make a manual, textbook, or other functional and useful document free in the sense of freedom: to assure everyone the effective freedom to copy and redistribute it, with or without modifying it, either commercially or noncommercially. Secondarily, this License preserves for the author and publisher a way to get credit for their work, while not being considered responsible for modifications made by others.

   This License is a kind of “copyleft”, which means that derivative works of the document must themselves be free in the same sense. It complements the GNU General Public License, which is a copyleft license designed for free software.

   We have designed this License in order to use it for manuals for free software, because free software needs free documentation: a free program should come with manuals providing the same freedoms that the software does. But this License is not limited to software manuals; it can be used for any textual work, regardless of subject matter or whether it is published as a printed book. We recommend this License principally for works whose purpose is instruction or reference.

2. APPLICABILITY AND DEFINITIONS

   This License applies to any manual or other work, in any medium, that contains a notice placed by the copyright holder saying it can be distributed under the terms of this License. Such a notice grants a world-wide, royalty-free license, unlimited in duration, to use that work under the conditions stated herein. The “Document”, below, refers to any such manual or work. Any member of the public is a licensee, and is addressed as “you”. You accept the license if you copy, modify or distribute the work in a way requiring permission under copyright law.

   A “Modified Version” of the Document means any work containing the Document or a portion of it, either copied verbatim, or with modifications and/or translated into another language.

   A “Secondary Section” is a named appendix or a front-matter section of the Document that deals exclusively with the relationship of the publishers or authors of the Document to the Document’s overall subject (or to related matters) and contains nothing that could fall directly within that overall subject. (Thus, if the Document is in part a textbook of mathematics, a Secondary Section may not explain any mathematics.) The relationship could be a matter of historical connection with the subject or with related matters, or of legal, commercial, philosophical, ethical or political position regarding them.

   The “Invariant Sections” are certain Secondary Sections whose titles are designated, as being those of Invariant Sections, in the notice that says that the Document is released under this License. If a section does not fit the above definition of Secondary then it is not allowed to be designated as Invariant. The Document may contain zero Invariant Sections. If the Document does not identify any Invariant Sections then there are none.

   The “Cover Texts” are certain short passages of text that are listed, as Front-Cover Texts or Back-Cover Texts, in the notice that says that the Document is released under this License. A Front-Cover Text may be at most 5 words, and a Back-Cover Text may be at most 25 words.

   A “Transparent” copy of the Document means a machine-readable copy, represented in a format whose specification is available to the general public, that is suitable for revising the document straightforwardly with generic text editors or (for images composed of pixels) generic paint programs or (for drawings) some widely available drawing editor, and that is suitable for input to text formatters or for automatic translation to a variety of formats suitable for input to text formatters. A copy made in an otherwise Transparent file format whose markup, or absence of markup, has been arranged to thwart or discourage subsequent modification by readers is not Transparent. An image format is not Transparent if used for any substantial amount of text. A copy that is not “Transparent” is called “Opaque”.

   Examples of suitable formats for Transparent copies include plain ASCII without markup, Texinfo input format, LaTeX input format, SGML or XML using a publicly available DTD, and standard-conforming simple HTML, PostScript or PDF designed for human modification. Examples of transparent image formats include PNG, XCF and JPG. Opaque formats include proprietary formats that can be read and edited only by proprietary word processors, SGML or XML for which the DTD and/or processing tools are not generally available, and the machine-generated HTML, PostScript or PDF produced by some word processors for output purposes only.

   The “Title Page” means, for a printed book, the title page itself, plus such following pages as are needed to hold, legibly, the material this License requires to appear in the title page. For works in formats which do not have any title page as such, “Title Page” means the text near the most prominent appearance of the work’s title, preceding the beginning of the body of the text.

   A section “Entitled XYZ” means a named subunit of the Document whose title either is precisely XYZ or contains XYZ in parentheses following text that translates XYZ in another language. (Here XYZ stands for a specific section name mentioned below, such as “Acknowledgements”, “Dedications”, “Endorsements”, or “History”.) To “Preserve the Title” of such a section when you modify the Document means that it remains a section “Entitled XYZ” according to this definition.

   The Document may include Warranty Disclaimers next to the notice which states that this License applies to the Document. These Warranty Disclaimers are considered to be included by reference in this License, but only as regards disclaiming warranties: any other implication that these Warranty Disclaimers may have is void and has no effect on the meaning of this License.

3. VERBATIM COPYING

   You may copy and distribute the Document in any medium, either commercially or noncommercially, provided that this License, the copyright notices, and the license notice saying this License applies to the Document are reproduced in all copies, and that you add no other conditions whatsoever to those of this License. You may not use technical measures to obstruct or control the reading or further copying of the copies you make or distribute. However, you may accept compensation in exchange for copies. If you distribute a large enough number of copies you must also follow the conditions in section 3.

   You may also lend copies, under the same conditions stated above, and you may publicly display copies.

4. COPYING IN QUANTITY

   If you publish printed copies (or copies in media that commonly have printed covers) of the Document, numbering more than 100, and the Document’s license notice requires Cover Texts, you must enclose the copies in covers that carry, clearly and legibly, all these Cover Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on the back cover. Both covers must also clearly and legibly identify you as the publisher of these copies. The front cover must present the full title with all words of the title equally prominent and visible. You may add other material on the covers in addition. Copying with changes limited to the covers, as long as they preserve the title of the Document and satisfy these conditions, can be treated as verbatim copying in other respects.

   If the required texts for either cover are too voluminous to fit legibly, you should put the first ones listed (as many as fit reasonably) on the actual cover, and continue the rest onto adjacent pages.

   If you publish or distribute Opaque copies of the Document numbering more than 100, you must either include a machine-readable Transparent copy along with each Opaque copy, or state in or with each Opaque copy a computer-network location from which the general network-using public has access to download using public-standard network protocols a complete Transparent copy of the Document, free of added material. If you use the latter option, you must take reasonably prudent steps, when you begin distribution of Opaque copies in quantity, to ensure that this Transparent copy will remain thus accessible at the stated location until at least one year after the last time you distribute an Opaque copy (directly or through your agents or retailers) of that edition to the public.

   It is requested, but not required, that you contact the authors of the Document well before redistributing any large number of copies, to give them a chance to provide you with an updated version of the Document.

5. MODIFICATIONS

   You may copy and distribute a Modified Version of the Document under the conditions of sections 2 and 3 above, provided that you release the Modified Version under precisely this License, with the Modified Version filling the role of the Document, thus licensing distribution and modification of the Modified Version to whoever possesses a copy of it. In addition, you must do these things in the Modified Version:

   1. Use in the Title Page (and on the covers, if any) a title distinct from that of the Document, and from those of previous versions (which should, if there were any, be listed in the History section of the Document). You may use the same title as a previous version if the original publisher of that version gives permission.
   2. List on the Title Page, as authors, one or more persons or entities responsible for authorship of the modifications in the Modified Version, together with at least five of the principal authors of the Document (all of its principal authors, if it has fewer than five), unless they release you from this requirement.
   3. State on the Title page the name of the publisher of the Modified Version, as the publisher.
   4. Preserve all the copyright notices of the Document.
   5. Add an appropriate copyright notice for your modifications adjacent to the other copyright notices.
   6. Include, immediately after the copyright notices, a license notice giving the public permission to use the Modified Version under the terms of this License, in the form shown in the Addendum below.
   7. Preserve in that license notice the full lists of Invariant Sections and required Cover Texts given in the Document’s license notice.
   8. Include an unaltered copy of this License.
   9. Preserve the section Entitled “History”, Preserve its Title, and add to it an item stating at least the title, year, new authors, and publisher of the Modified Version as given on the Title Page. If there is no section Entitled “History” in the Document, create one stating the title, year, authors, and publisher of the Document as given on its Title Page, then add an item describing the Modified Version as stated in the previous sentence.
   10. Preserve the network location, if any, given in the Document for public access to a Transparent copy of the Document, and likewise the network locations given in the Document for previous versions it was based on. These may be placed in the “History” section. You may omit a network location for a work that was published at least four years before the Document itself, or if the original publisher of the version it refers to gives permission.
   11. For any section Entitled “Acknowledgements” or “Dedications”, Preserve the Title of the section, and preserve in the section all the substance and tone of each of the contributor acknowledgements and/or dedications given therein.
   12. Preserve all the Invariant Sections of the Document, unaltered in their text and in their titles. Section numbers or the equivalent are not considered part of the section titles.
   13. Delete any section Entitled “Endorsements”. Such a section may not be included in the Modified Version.
   14. Do not retitle any existing section to be Entitled “Endorsements” or to conflict in title with any Invariant Section.
   15. Preserve any Warranty Disclaimers.

   If the Modified Version includes new front-matter sections or appendices that qualify as Secondary Sections and contain no material copied from the Document, you may at your option designate some or all of these sections as invariant. To do this, add their titles to the list of Invariant Sections in the Modified Version’s license notice. These titles must be distinct from any other section titles.

   You may add a section Entitled “Endorsements”, provided it contains nothing but endorsements of your Modified Version by various parties—for example, statements of peer review or that the text has been approved by an organization as the authoritative definition of a standard.

   You may add a passage of up to five words as a Front-Cover Text, and a passage of up to 25 words as a Back-Cover Text, to the end of the list of Cover Texts in the Modified Version. Only one passage of Front-Cover Text and one of Back-Cover Text may be added by (or through arrangements made by) any one entity. If the Document already includes a cover text for the same cover, previously added by you or by arrangement made by the same entity you are acting on behalf of, you may not add another; but you may replace the old one, on explicit permission from the previous publisher that added the old one.

   The author(s) and publisher(s) of the Document do not by this License give permission to use their names for publicity for or to assert or imply endorsement of any Modified Version.

6. COMBINING DOCUMENTS

   You may combine the Document with other documents released under this License, under the terms defined in section 4 above for modified versions, provided that you include in the combination all of the Invariant Sections of all of the original documents, unmodified, and list them all as Invariant Sections of your combined work in its license notice, and that you preserve all their Warranty Disclaimers.

   The combined work need only contain one copy of this License, and multiple identical Invariant Sections may be replaced with a single copy. If there are multiple Invariant Sections with the same name but different contents, make the title of each such section unique by adding at the end of it, in parentheses, the name of the original author or publisher of that section if known, or else a unique number. Make the same adjustment to the section titles in the list of Invariant Sections in the license notice of the combined work.

   In the combination, you must combine any sections Entitled “History” in the various original documents, forming one section Entitled “History”; likewise combine any sections Entitled “Acknowledgements”, and any sections Entitled “Dedications”. You must delete all sections Entitled “Endorsements.”

7. COLLECTIONS OF DOCUMENTS

   You may make a collection consisting of the Document and other documents released under this License, and replace the individual copies of this License in the various documents with a single copy that is included in the collection, provided that you follow the rules of this License for verbatim copying of each of the documents in all other respects.

   You may extract a single document from such a collection, and distribute it individually under this License, provided you insert a copy of this License into the extracted document, and follow this License in all other respects regarding verbatim copying of that document.

8. AGGREGATION WITH INDEPENDENT WORKS

   A compilation of the Document or its derivatives with other separate and independent documents or works, in or on a volume of a storage or distribution medium, is called an “aggregate” if the copyright resulting from the compilation is not used to limit the legal rights of the compilation’s users beyond what the individual works permit. When the Document is included in an aggregate, this License does not apply to the other works in the aggregate which are not themselves derivative works of the Document.

   If the Cover Text requirement of section 3 is applicable to these copies of the Document, then if the Document is less than one half of the entire aggregate, the Document’s Cover Texts may be placed on covers that bracket the Document within the aggregate, or the electronic equivalent of covers if the Document is in electronic form. Otherwise they must appear on printed covers that bracket the whole aggregate.

9. TRANSLATION

   Translation is considered a kind of modification, so you may distribute translations of the Document under the terms of section 4. Replacing Invariant Sections with translations requires special permission from their copyright holders, but you may include translations of some or all Invariant Sections in addition to the original versions of these Invariant Sections. You may include a translation of this License, and all the license notices in the Document, and any Warranty Disclaimers, provided that you also include the original English version of this License and the original versions of those notices and disclaimers. In case of a disagreement between the translation and the original version of this License or a notice or disclaimer, the original version will prevail.

   If a section in the Document is Entitled “Acknowledgements”, “Dedications”, or “History”, the requirement (section 4) to Preserve its Title (section 1) will typically require changing the actual title.

10. TERMINATION

    You may not copy, modify, sublicense, or distribute the Document except as expressly provided for under this License. Any other attempt to copy, modify, sublicense or distribute the Document is void, and will automatically terminate your rights under this License. However, parties who have received copies, or rights, from you under this License will not have their licenses terminated so long as such parties remain in full compliance.

11. FUTURE REVISIONS OF THIS LICENSE

    The Free Software Foundation may publish new, revised versions of the GNU Free Documentation License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns. See http://www.gnu.org/copyleft/.

    Each version of the License is given a distinguishing version number. If the Document specifies that a particular numbered version of this License “or any later version” applies to it, you have the option of following the terms and conditions either of that specified version or of any later version that has been published (not as a draft) by the Free Software Foundation. If the Document does not specify a version number of this License, you may choose any version ever published (not as a draft) by the Free Software Foundation.

ADDENDUM: How to use this License for your documents

To use this License in a document you have written, include a copy of the License in the document and put the following copyright and license notices just after the title page:

  Copyright (C)  year  your name.
  Permission is granted to copy, distribute and/or modify this document
  under the terms of the GNU Free Documentation License, Version 1.2
  or any later version published by the Free Software Foundation;
  with no Invariant Sections, no Front-Cover Texts, and no Back-Cover
  Texts.  A copy of the license is included in the section entitled ``GNU
  Free Documentation License''.

If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts, replace the “with…Texts.” line with this:

    with the Invariant Sections being list their titles, with
    the Front-Cover Texts being list, and with the Back-Cover Texts
    being list.

If you have Invariant Sections without Cover Texts, or some other combination of the three, merge those two alternatives to suit the situation.

If your document contains nontrivial examples of program code, we recommend releasing these examples in parallel under your choice of free software license, such as the GNU General Public License, to permit their use in free software.

1.4 Bibliography

[IEEE]

IEEE Standard 1178-1990. IEEE Standard for the Scheme Programming Language. IEEE, New York, 1991.

[R4RS]

William Clinger and Jonathan Rees, Editors. <A HREF="r4rs_toc.html"> Revised(4) Report on the Algorithmic Language Scheme. </A> ACM Lisp Pointers Volume IV, Number 3 (July-September 1991), pp. 1-55.

[R5RS]

Richard Kelsey and William Clinger and Jonathan (Rees, editors) <A HREF="r5rs_toc.html"> Revised(5) Report on the Algorithmic Language Scheme. </A> Higher-Order and Symbolic Computation Volume 11, Number 1 (1998), pp. 7-105, and ACM SIGPLAN Notices 33(9), September 1998.

[Exrename]

William Clinger <A HREF="http://www.cs.indiana.edu/scheme-repository/doc.proposals.html"> Hygienic Macros Through Explicit Renaming </A> Lisp Pointers Volume IV, Number 4 (December 1991), pp 17-23.

[SICP]

Harold Abelson and Gerald Jay Sussman with Julie Sussman. Structure and Interpretation of Computer Programs. MIT Press, Cambridge, 1985.

[Simply]

Brian Harvey and Matthew Wright. <A HREF="http://HTTP.CS.Berkeley.EDU/~bh/simply-toc.html"> Simply Scheme: Introducing Computer Science </A> MIT Press, 1994 ISBN 0-262-08226-8

[SchemePrimer]

犬飼大(Dai Inukai) <A HREF="http://www.shuwasystem.co.jp/SchemePrimer/"> 入門Scheme </A> 1999年12月初版 ISBN4-87966-954-7

[SLIB]

Todd R. Eigenschink, Dave Love, and Aubrey Jaffer. <A HREF="slib_toc.html"> SLIB, The Portable Scheme Library. </A> Version 2c8, June 2000.

[JACAL]

Aubrey Jaffer. <A HREF="jacal_toc.html"> JACAL Symbolic Mathematics System. </A> Version 1b0, Sep 1999.

‘scm.texi’

‘scm.info’

Documentation of scm extensions (beyond Scheme standards). Documentation on the internal representation and how to extend or include scm in other programs.

‘Xlibscm.texi’

‘Xlibscm.info’

Documentation of the Xlib - SCM Language X Interface.

2. Installing SCM

2.1 Making SCM

The SCM distribution has Makefile which contains rules for making scmlit, a “bare-bones” version of SCM sufficient for running ‘build’. ‘build’ is used to compile (or create scripts to compile) full featured versions (see section Building SCM).

Makefiles are not portable to the majority of platforms. If ‘Makefile’ works for you, good; If not, I don’t want to hear about it. If you need to compile SCM without build, there are several ways to proceed:

• Use the build web page to create custom batch scripts for compiling SCM.
• Use SCM on a different platform to run ‘build’ to create a script to build SCM;
• Use another implementation of Scheme to run ‘build’ to create a script to build SCM;
• Create your own script or ‘Makefile’.

2.2 SLIB

[SLIB] is a portable Scheme library meant to provide compatibility and utility functions for all standard Scheme implementations. Although SLIB is not neccessary to run SCM, I strongly suggest you obtain and install it. Bug reports about running SCM without SLIB have very low priority. SLIB is available from the same sites as SCM:

• <A HREF="http://swiss.csail.mit.edu/ftpdir/scm/slib-3b1.zip"> http://swiss.csail.mit.edu/ftpdir/scm/slib-3b1.zip </A>
• <A HREF="ftp://ftp.gnu.org/pub/gnu/jacal/slib-3b1.tar.gz"> ftp.gnu.org:/pub/gnu/jacal/slib-3b1.tar.gz </A>

Unpack SLIB (‘tar xzf slib-3b1.tar.gz’ or ‘unzip -ao slib-3b1.zip’) in an appropriate directory for your system; both tar and unzip will create the directory ‘slib’.

Then create a file ‘require.scm’ in the SCM implementation-vicinity (this is the same directory as where the file ‘Init5e5.scm’ is installed). ‘require.scm’ should have the contents:

(define (library-vicinity) "/usr/local/lib/slib/")

where the pathname string ‘/usr/local/lib/slib/’ is to be replaced by the pathname into which you installed SLIB. Absolute pathnames are recommended here; if you use a relative pathname, SLIB can get confused when the working directory is changed (see section chmod). The way to specify a relative pathname is to append it to the implementation-vicinity, which is absolute:

(define library-vicinity
  (let ((lv (string-append (implementation-vicinity) "../slib/")))
    (lambda () lv)))

Alternatively, you can set the (shell) environment variable SCHEME_LIBRARY_PATH to the pathname of the SLIB directory (see section Environment Variables). If set, the environment variable overrides ‘require.scm’. Again, absolute pathnames are recommended.

2.3 Building SCM

The file build loads the file build.scm, which constructs a relational database of how to compile and link SCM executables. ‘build.scm’ has information for the platforms which SCM has been ported to (of which I have been notified). Some of this information is old, incorrect, or incomplete. Send corrections and additions to jaffer @ ai.mit.edu.

2.3.1 Invoking Build

The all method will also work for MS-DOS and unix. Use the all method if you encounter problems with ‘build’.

MS-DOS

From the SCM source directory, type ‘build’ followed by up to 9 command line arguments.

unix

From the SCM source directory, type ‘./build’ followed by command line arguments.

all

From the SCM source directory, start ‘scm’ or ‘scmlit’ and type (load "build"). Alternatively, start ‘scm’ or ‘scmlit’ with the command line argument ‘-ilbuild’.

Invoking build without the ‘-F’ option will build or create a shell script with the arrays, inexact, and bignums options as defaults.

bash$ ./build
-|
#! /bin/sh
# unix (linux) script created by SLIB/batch 
# ================ Write file with C defines
rm -f scmflags.h
echo '#define IMPLINIT "Init5e5.scm"'>>scmflags.h
echo '#define BIGNUMS'>>scmflags.h
echo '#define FLOATS'>>scmflags.h
echo '#define ARRAYS'>>scmflags.h
# ================ Compile C source files
gcc -O2 -c continue.c scm.c scmmain.c findexec.c script.c time.c repl.c scl.c eval.c sys.c subr.c debug.c unif.c rope.c
# ================ Link C object files
gcc -rdynamic -o scm continue.o scm.o scmmain.o findexec.o script.o time.o repl.o scl.o eval.o sys.o subr.o debug.o unif.o rope.o -lm -lc

To cross compile for another platform, invoke build with the ‘-p’ or ‘--platform=’ option. This will create a script for the platform named in the ‘-p’ or ‘--platform=’ option.

bash$ ./build -o scmlit -p darwin -F lit
-|
#! /bin/sh
# unix (darwin) script created by SLIB/batch 
# ================ Write file with C defines
rm -f scmflags.h
echo '#define IMPLINIT "Init5e5.scm"'>>scmflags.h
# ================ Compile C source files
cc -O3 -c continue.c scm.c scmmain.c findexec.c script.c time.c repl.c scl.c eval.c sys.c subr.c debug.c unif.c rope.c
# ================ Link C object files
mv -f scmlit scmlit~
cc -o scmlit continue.o scm.o scmmain.o findexec.o script.o time.o repl.o scl.o eval.o sys.o subr.o debug.o unif.o rope.o

2.3.2 Build Options

The options to build specify what, where, and how to build a SCM program or dynamically linked module. These options are unrelated to the SCM command line options.

Build Option: -p platform-name

Build Option: ---platform=platform-name

specifies that the compilation should be for a computer/operating-system combination called platform-name. Note The case of platform-name is distinguised. The current platform-names are all lower-case.

The platforms defined by table platform in ‘build.scm’ are:

Table: platform
name              processor         operating-system  compiler          
#f                processor-family  operating-system  #f                
symbol            processor-family  operating-system  symbol            
symbol            symbol            symbol            symbol            
================= ================= ================= ================= 
*unknown*         *unknown*         unix              cc                
acorn-unixlib     acorn             *unknown*         cc                
aix               powerpc           aix               cc                
alpha-elf         alpha             unix              cc                
alpha-linux       alpha             linux             gcc               
amiga-aztec       m68000            amiga             cc                
amiga-dice-c      m68000            amiga             dcc               
amiga-gcc         m68000            amiga             gcc               
amiga-sas         m68000            amiga             lc                
atari-st-gcc      m68000            atari-st          gcc               
atari-st-turbo-c  m68000            atari-st          tcc               
borland-c         i8086             ms-dos            bcc               
darwin            powerpc           unix              cc                
djgpp             i386              ms-dos            gcc               
freebsd           *unknown*         unix              cc                
gcc               *unknown*         unix              gcc               
gnu-win32         i386              unix              gcc               
highc             i386              ms-dos            hc386             
hp-ux             hp-risc           hp-ux             cc                
irix              mips              irix              gcc               
linux             *unknown*         linux             gcc               
linux-aout        i386              linux             gcc               
linux-ia64        ia64              linux             gcc               
microsoft-c       i8086             ms-dos            cl                
microsoft-c-nt    i386              ms-dos            cl                
microsoft-quick-c i8086             ms-dos            qcl               
ms-dos            i8086             ms-dos            cc                
netbsd            *unknown*         unix              gcc               
openbsd           *unknown*         unix              gcc               
os/2-cset         i386              os/2              icc               
os/2-emx          i386              os/2              gcc               
osf1              alpha             unix              cc                
plan9-8           i386              plan9             8c                
sunos             sparc             sunos             cc                
svr4              *unknown*         unix              cc                
svr4-gcc-sun-ld   sparc             sunos             gcc               
turbo-c           i8086             ms-dos            tcc               
unicos            cray              unicos            cc                
unix              *unknown*         unix              cc                
vms               vax               vms               cc                
vms-gcc           vax               vms               gcc               
watcom-9.0        i386              ms-dos            wcc386p           

Build Option: -f pathname

specifies that the build options contained in pathname be spliced into the argument list at this point. The use of option files can separate functional features from platform-specific ones.

The ‘Makefile’ calls out builds with the options in ‘.opt’ files:

‘dlls.opt’

Options for Makefile targets mydlls, myturtle, and x.so.

‘gdb.opt’

Options for udgdbscm and gdbscm.

‘libscm.opt’

Options for libscm.a.

‘pg.opt’

Options for pgscm, which instruments C functions.

‘udscm4.opt’

Options for targets udscm4 and dscm4 (scm).

‘udscm5.opt’

Options for targets udscm5 and dscm5 (scm).

The Makefile creates options files it depends on only if they do not already exist.

Build Option: -o filename

Build Option: ---outname=filename

specifies that the compilation should produce an executable or object name of filename. The default is ‘scm’. Executable suffixes will be added if neccessary, e.g. ‘scm’ ⇒ ‘scm.exe’.

Build Option: -l libname …

Build Option: ---libraries=libname

specifies that the libname should be linked with the executable produced. If compile flags or include directories (‘-I’) are needed, they are automatically supplied for compilations. The ‘c’ library is always included. SCM features specify any libraries they need; so you shouldn’t need this option often.

Build Option: -D definition …

Build Option: ---defines=definition

specifies that the definition should be made in any C source compilations. If compile flags or include directories (‘-I’) are needed, they are automatically supplied for compilations. SCM features specify any flags they need; so you shouldn’t need this option often.

Build Option: ---compiler-options=flag

specifies that that flag will be put on compiler command-lines.

Build Option: ---linker-options=flag

specifies that that flag will be put on linker command-lines.

Build Option: -s pathname

Build Option: ---scheme-initial=pathname

specifies that pathname should be the default location of the SCM initialization file ‘Init5e5.scm’. SCM tries several likely locations before resorting to pathname (see section File-System Habitat). If not specified, the current directory (where build is building) is used.

Build Option: -c pathname …

Build Option: ---c-source-files=pathname

specifies that the C source files pathname … are to be compiled.

Build Option: -j pathname …

Build Option: ---object-files=pathname

specifies that the object files pathname … are to be linked.

Build Option: -i call …

Build Option: ---initialization=call

specifies that the C functions call … are to be invoked during initialization.

Build Option: -t build-what

Build Option: ---type=build-what

specifies in general terms what sort of thing to build. The choices are:

‘exe’

executable program.

‘lib’

library module.

‘dlls’

archived dynamically linked library object files.

‘dll’

dynamically linked library object file.

The default is to build an executable.

Build Option: -h batch-syntax

Build Option: --batch-dialect=batch-syntax

specifies how to build. The default is to create a batch file for the host system. The SLIB file ‘batch.scm’ knows how to create batch files for:

• unix
• dos
• vms
• amigaos (was amigados)
• system

  This option executes the compilation and linking commands through the use of the system procedure.

• *unknown*

  This option outputs Scheme code.

Build Option: -w batch-filename

Build Option: --script-name=batch-filename

specifies where to write the build script. The default is to display it on (current-output-port).

Build Option: -F feature …

Build Option: ---features=feature

specifies to build the given features into the executable. The defined features are:

array

Alias for ARRAYS

array-for-each

array-map! and array-for-each (arrays must also be featured).

arrays

Use if you want arrays, uniform-arrays and uniform-vectors.

bignums

Large precision integers.

byte

Treating strings as byte-vectors.

byte-number

Byte/number conversions

careful-interrupt-masking

Define this for extra checking of interrupt masking and some simple checks for proper use of malloc and free. This is for debugging C code in ‘sys.c’, ‘eval.c’, ‘repl.c’ and makes the interpreter several times slower than usual.

cautious

Normally, the number of arguments arguments to interpreted closures (from LAMBDA) are checked if the function part of a form is not a symbol or only the first time the form is executed if the function part is a symbol. defining ‘reckless’ disables any checking. If you want to have SCM always check the number of arguments to interpreted closures define feature ‘cautious’.

cheap-continuations

If you only need straight stack continuations, executables compile with this feature will run faster and use less storage than not having it. Machines with unusual stacks need this. Also, if you incorporate new C code into scm which uses VMS system services or library routines (which need to unwind the stack in an ordrly manner) you may need to use this feature.

compiled-closure

Use if you want to use compiled closures.

curses

For the curses screen management package.

debug

Turns on the features ‘cautious’ and ‘careful-interrupt-masking’; uses -g flags for debugging SCM source code.

differ

Sequence comparison

dont-memoize-locals

SCM normally converts references to local variables to ILOCs, which make programs run faster. If SCM is badly broken, try using this option to disable the MEMOIZE_LOCALS feature.

dump

Convert a running scheme program into an executable file.

dynamic-linking

Be able to load compiled files while running.

edit-line

interface to the editline or GNU readline library.

engineering-notation

Use if you want floats to display in engineering notation (exponents always multiples of 3) instead of scientific notation.

generalized-c-arguments

make_gsubr for arbitrary (< 11) arguments to C functions.

i/o-extensions

Commonly available I/O extensions: exec, line I/O, file positioning, file delete and rename, and directory functions.

inexact

Use if you want floating point numbers.

lit

Lightweight – no features

macro

C level support for hygienic and referentially transparent macros (syntax-rules macros).

mysql

Client connections to the mysql databases.

no-heap-shrink

Use if you want segments of unused heap to not be freed up after garbage collection. This may increase time in GC for *very* large working sets.

none

No features

posix

Posix functions available on all Unix-like systems. fork and process functions, user and group IDs, file permissions, and link.

reckless

If your scheme code runs without any errors you can disable almost all error checking by compiling all files with ‘reckless’.

record

The Record package provides a facility for user to define their own record data types. See SLIB for documentation.

regex

String regular expression matching.

rev2-procedures

These procedures were specified in the Revised^2 Report on Scheme but not in R4RS.

sicp

Use if you want to run code from:

Harold Abelson and Gerald Jay Sussman with Julie Sussman. Structure and Interpretation of Computer Programs. The MIT Press, Cambridge, Massachusetts, USA, 1985.

Differences from R5RS are:

• (eq? ’() ’#f)
• (define a 25) returns the symbol a.
• (set! a 36) returns 36.

single-precision-only

Use if you want all inexact real numbers to be single precision. This only has an effect if SINGLES is also defined (which is the default). This does not affect complex numbers.

socket

BSD socket interface. Socket addr functions require inexacts or bignums for 32-bit precision.

tick-interrupts

Use if you want the ticks and ticks-interrupt functions.

turtlegr

Turtle graphics calls for both Borland-C and X11 from sjm@ee.tut.fi.

unix

Those unix features which have not made it into the Posix specs: nice, acct, lstat, readlink, symlink, mknod and sync.

wb

WB database with relational wrapper.

windows

Microsoft Windows executable.

x

Alias for Xlib feature.

xlib

Interface to Xlib graphics routines.

2.3.3 Compiling and Linking Custom Files

A correspondent asks:

How can we link in our own c files to the SCM interpreter so that we can add our own functionality? (e.g. we have a bunch of tcp functions we want access to). Would this involve changing build.scm or the Makefile or both?

(see section Changing Scm has instructions describing the C code format). Suppose a C file foo.c has functions you wish to add to SCM. To compile and link your file at compile time, use the ‘-c’ and ‘-i’ options to build:

bash$ ./build -c foo.c -i init_foo
-|
#! /bin/sh
rm -f scmflags.h
echo '#define IMPLINIT "/home/jaffer/scm/Init5e5.scm"'>>scmflags.h
echo '#define COMPILED_INITS init_foo();'>>scmflags.h
echo '#define BIGNUMS'>>scmflags.h
echo '#define FLOATS'>>scmflags.h
echo '#define ARRAYS'>>scmflags.h
gcc -O2 -c continue.c scm.c findexec.c script.c time.c repl.c scl.c \
        eval.c sys.c subr.c unif.c rope.c foo.c
gcc -rdynamic -o scm continue.o scm.o findexec.o script.o time.o \
        repl.o scl.o eval.o sys.o subr.o unif.o rope.o foo.o -lm -lc

To make a dynamically loadable object file use the -t dll option:

bash$ ./build -t dll -c foo.c
-|
#! /bin/sh
rm -f scmflags.h
echo '#define IMPLINIT "/home/jaffer/scm/Init5e5.scm"'>>scmflags.h
echo '#define BIGNUMS'>>scmflags.h
echo '#define FLOATS'>>scmflags.h
echo '#define ARRAYS'>>scmflags.h
echo '#define DLL'>>scmflags.h
gcc -O2 -fpic -c foo.c
gcc -shared -o foo.so foo.o -lm -lc

Once ‘foo.c’ compiles correctly (and your SCM build supports dynamic-loading), you can load the compiled file with the Scheme command (load "./foo.so"). See Configure Module Catalog for how to add a compiled dll file to SLIB’s catalog.

2.4 Installing Dynamic Linking

Dynamic linking has not been ported to all platforms. Operating systems in the BSD family (a.out binary format) can usually be ported to DLD. The dl library (#define SUN_DL for SCM) was a proposed POSIX standard and may be available on other machines with COFF binary format. For notes about porting to MS-Windows and finishing the port to VMS VMS Dynamic Linking.

DLD is a library package of C functions that performs dynamic link editing on GNU/Linux, VAX (Ultrix), Sun 3 (SunOS 3.4 and 4.0), SPARCstation (SunOS 4.0), Sequent Symmetry (Dynix), and Atari ST. It is available from:

<A HREF="ftp://ftp.gnu.org/pub/gnu/dld-3.3.tar.gz"> ftp.gnu.org:pub/gnu/dld-3.3.tar.gz </A>

These notes about using libdl on SunOS are from ‘gcc.info’:

On a Sun, linking using GNU CC fails to find a shared library and reports that the library doesn’t exist at all.

This happens if you are using the GNU linker, because it does only static linking and looks only for unshared libraries. If you have a shared library with no unshared counterpart, the GNU linker won’t find anything.

We hope to make a linker which supports Sun shared libraries, but please don’t ask when it will be finished–we don’t know.

Sun forgot to include a static version of ‘libdl.a’ with some versions of SunOS (mainly 4.1). This results in undefined symbols when linking static binaries (that is, if you use ‘-static’). If you see undefined symbols ‘_dlclose’, ‘_dlsym’ or ‘_dlopen’ when linking, compile and link against the file ‘mit/util/misc/dlsym.c’ from the MIT version of X windows.