1.1 Manual (Pdf)

Total Page:16

File Type:pdf, Size:1020Kb

1.1 Manual (Pdf) The Incomplete Scheme 48 Reference Manual for release 1.1 Richard Kelsey Jonathan Rees Mike Sperber A line may take us hours, yet if it does not seem a moment’s thought All our stitching and unstitching has been as nought. Yeats Adam’s Curse ii Acknowledgements Thanks to Scheme 48’s users for their suggestions, bug reports, and forbearance. Thanks also to Deborah Tatar for providing the Yeats quotation. iii Contents 1 Introduction 1 2 User’s guide 2 2.1 Command line arguments . 2 2.2 Command processor . 3 2.3 Editing . 3 2.4 Performance . 3 2.5 Disassembler . 4 2.6 Module system . 4 2.7 Library . 5 3 Command processor 7 3.1 Current focus value and ## .......................... 7 3.2 Command levels . 8 3.3 Logistical commands . 8 3.4 Module commands . 9 3.5 Debugging commands . 9 3.6 Switches . 10 3.7 Inspection mode . 12 3.8 Command programs . 13 3.9 Building images . 14 3.10 Resource query and control . 14 3.11 Threads . 15 3.12 Quite obscure . 16 4 Module system 17 4.1 Introduction . 17 4.2 The configuration language . 18 4.3 Interfaces . 20 4.4 Macros . 21 4.5 Higher-order modules . 21 4.6 Compiling and linking . 21 4.7 Semantics of configuration mutation . 22 4.8 Command processor support . 23 4.9 Configuration packages . 25 4.10 Discussion . 27 iv 5 Libraries 29 5.1 General utilities . 29 5.2 Pretty-printing . 30 5.3 ASCII character encoding . 31 5.4 Bitwise integer operations . 31 5.5 Byte vectors . 31 5.6 Sparse vectors . 32 5.7 Cells . 32 5.8 Queues . 32 5.9 Arrays . 33 5.10 Records . 34 5.10.1 Low-level access to records . 35 5.10.2 Record types . 36 5.11 Finite record types . 37 5.12 Sets over finite types . 38 5.13 Hash tables . 39 5.14 Port extensions . 40 5.15 Fluid bindings . 41 5.16 Shell commands . 42 5.17 Sockets . 43 5.18 Macros for writing loops . 44 5.18.1 Iterate ................................. 44 5.18.2 Reduce ................................. 45 5.18.3 Sequence types . 45 5.18.4 Synchronous sequences . 46 5.18.5 Examples . 47 5.18.6 Defining sequence types . 48 5.18.7 Expanded code . 48 5.19 Sorting lists and vectors . 49 5.19.1 Design rules . 49 5.19.2 Procedure specification . 52 5.19.3 Algorithmic properties . 59 5.20 Regular expressions . 60 5.20.1 Character sets . 60 5.20.2 Anchoring . 61 5.20.3 Composite expressions . 61 5.20.4 Case sensitivity . 61 5.20.5 Submatches and matching . 62 5.21 SRFIs . 63 6 Threads 66 6.1 Creating and controlling threads . 66 6.2 Advanced thread handling . 67 6.3 Debugging multithreaded programs . 67 6.4 Optimistic concurrency . 67 6.5 Condition variables . 70 6.6 Mutual exclusion . 71 v 6.6.1 Locks . 71 6.6.2 Placeholders . 72 6.7 Writing custom synchronization abstractions . 72 7 Mixing Scheme 48 and C 74 7.1 Available facilities . 74 7.1.1 Scheme structures . 74 7.1.2 C naming conventions . 74 7.1.3 Garbage collection . 75 7.2 Shared bindings . 75 7.2.1 Exporting Scheme values to C . 75 7.2.2 Exporting C values to Scheme . 75 7.2.3 Complete shared binding interface . 76 7.3 Calling C functions from Scheme . 77 7.4 Adding external modules to the Makefile . 77 7.5 Dynamic loading . 78 7.6 Compatibility . 79 7.7 Accessing Scheme data from C . 79 7.7.1 Constants . 79 7.7.2 Converting values . 79 7.7.3 C versions of Scheme procedures . 80 7.8 Calling Scheme functions from C . 81 7.9 Interacting with the Scheme heap . 82 7.9.1 Registering objects with the GC . 82 7.9.2 Keeping C data structures in the Scheme heap . 82 7.9.3 C code and heap images . 83 7.10 Using Scheme records in C code . 83 7.11 Raising exceptions from external code . 84 7.12 Unsafe functions and macros . 85 8 Access to POSIX 87 8.1 Process primitives . 87 8.1.1 Process creation and termination . 87 8.1.2 Exec ................................... 88 8.2 Signals . 89 8.2.1 POSIX signals . 89 8.2.2 Other signals . 90 8.2.3 Sending signals . 91.
Recommended publications
  • Towards a Portable and Mobile Scheme Interpreter
    Towards a Portable and Mobile Scheme Interpreter Adrien Pi´erard Marc Feeley Universit´eParis 6 Universit´ede Montr´eal [email protected] [email protected] Abstract guage. Because Mobit implements R4RS Scheme [6], we must also The transfer of program data between the nodes of a distributed address the serialization of continuations. Our main contribution is system is a fundamental operation. It usually requires some form the demonstration of how this can be done while preserving the in- of data serialization. For a functional language such as Scheme it is terpreter’s maintainability and with local changes to the original in- clearly desirable to also allow the unrestricted transfer of functions terpreter’s structure, mainly through the use of unhygienic macros. between nodes. With the goal of developing a portable implemen- We start by giving an overview of the pertinent features of the tation of the Termite system we have designed the Mobit Scheme Termite dialect of Scheme. In Section 3 we explain the structure interpreter which supports unrestricted serialization of Scheme ob- of the interpreter on which Mobit is based. Object serialization is jects, including procedures and continuations. Mobit is derived discussed in Section 4. Section 5 compares Mobit’s performance from an existing Scheme in Scheme fast interpreter. We demon- with other interpreters. We conclude with related and future work. strate how macros were valuable in transforming the interpreter while preserving its structure and maintainability. Our performance 2. Termite evaluation shows that the run time speed of Mobit is comparable to Termite is a Scheme adaptation of the Erlang concurrency model.
    [Show full text]
  • Towards a Portable and Mobile Scheme Interpreter
    Towards a Portable and Mobile Scheme Interpreter Adrien Pi´erard Marc Feeley Universit´eParis 6 Universit´ede Montr´eal [email protected] [email protected] Abstract guage. Because Mobit implements R4RS Scheme [6], we must also The transfer of program data between the nodes of a distributed address the serialization of continuations. Our main contribution is system is a fundamental operation. It usually requires some form the demonstration of how this can be done while preserving thein- of data serialization. For a functional language such as Scheme it is terpreter’s maintainability and with local changes to the original in- clearly desirable to also allow the unrestricted transfer offunctions terpreter’s structure, mainly through the use of unhygienicmacros. between nodes. With the goal of developing a portable implemen- We start by giving an overview of the pertinent features of the tation of the Termite system we have designed the Mobit Scheme Termite dialect of Scheme. In Section 3 we explain the structure interpreter which supports unrestricted serialization of Scheme ob- of the interpreter on which Mobit is based. Object serialization is jects, including procedures and continuations. Mobit is derived discussed in Section 4. Section 5 compares Mobit’s performance from an existing Scheme in Scheme fast interpreter. We demon- with other interpreters. We conclude with related and futurework. strate how macros were valuable in transforming the interpreter while preserving its structure and maintainability. Our performance 2. Termite evaluation shows that the run time speed of Mobit is comparable to Termite is a Scheme adaptation of the Erlang concurrency model.
    [Show full text]
  • Rash: from Reckless Interactions to Reliable Programs
    Rash: From Reckless Interactions to Reliable Programs William Gallard Hatch Matthew Flatt University of Utah University of Utah USA USA [email protected] [email protected] Abstract them along a spectrum of program maturity and scale. Mov- Command languages like the Bourne Shell provide a terse ing code along this scale is often viewed as a transition from syntax for exploratory programming and system interaction. “scripts” to more mature “programs,” and current research Shell users can begin to write programs that automate their aims to improve that transition, especially through grad- tasks by simply copying their interactions verbatim into a ual typing [18, 20]. In this paper, we address a point in the script file. However, command languages usually scale poorly spectrum that precedes even the “script” level of maturity: beyond small scripts, and they can be difficult to integrate command sequences in an interactive shell. into larger programs. General-purpose languages scale well, Different features and aspects of programming languages but are verbose and unwieldy for common interactive actions are well suited to different stages of program maturity. For such as process composition. example, static types are clearly useful for ensuring and We present Rash, a domain-specific command language maintaining software correctness, but types are often seen embedded in Racket. Rash provides a terse and extensible as burdensome or obstructive when writing scripts, so many syntax for interactive system administration and scripting, scripting languages eschew types. Programmers want brevity as well as easy composition of both Racket functions and and even less formality in interactive settings, so read-eval- operating system processes.
    [Show full text]
  • A Reader Framework for Guile for Guile-Reader 0.6.2
    A Reader Framework for Guile for Guile-Reader 0.6.2 Ludovic Court`es Edition 0.6.2 8 March 2017 This file documents Guile-Reader. Copyright c 2005, 2006, 2007, 2008, 2009, 2012, 2015, 2017 Ludovic Court`es Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the con- ditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Permission is granted to copy and distribute translations of this manual into another lan- guage, under the above conditions for modified versions, except that this permission notice may be stated in a translation approved by the Free Software Foundation. i Table of Contents A Reader Framework for Guile ................ 1 1 Introduction............................... 3 2 Overview .................................. 5 3 Quick Start................................ 7 4 API Reference............................. 9 4.1 Token Readers .............................................. 9 4.1.1 Defining a New Token Reader............................ 9 4.1.2 Token Reader Calling Convention ........................ 9 4.1.3 Invoking a Reader from a Token Reader ................. 10 4.1.4 Token Reader Library .................................. 11 4.1.5 Limitations............................................ 16 4.1.5.1 Token Delimiters .................................
    [Show full text]
  • Fully-Parameterized, First-Class Modules with Hygienic Macros
    Fully-parameterized, First-class Modules with Hygienic Macros Dissertation der Fakult¨at fur¨ Informations- und Kognitionswissenschaften der Eberhard-Karls-Universit¨at Tubingen¨ zur Erlangung des Grades eines Doktors der Naturwissenschaften (Dr. rer. nat.) vorgelegt von Dipl.-Inform. Josef Martin Gasbichler aus Biberach/Riß Tubingen¨ 2006 Tag der mundlichen¨ Qualifikation: 15. 02. 2006 Dekan: Prof. Dr. Michael Diehl 1. Berichterstatter: Prof. Dr. Herbert Klaeren 2. Berichterstatter: Prof. Dr. Peter Thiemann (Universit¨at Freiburg) Abstract It is possible to define a formal semantics for configuration, elaboration, linking, and evaluation of fully-parameterized first-class modules with hygienic macros, independent compilation, and code sharing. This dissertation defines such a semantics making use of explicit substitution to formalize hygienic expansion and linking. In the module system, interfaces define the static semantics of modules and include the definitions of exported macros. This enables full parameterization and independent compilation of modules even in the presence of macros. Thus modules are truly exchangeable components of the program. The basis for the module system is an operational semantics for hygienic macro expansion—computational macros as well as rewriting-based macros. The macro semantics provides deep insight into the nature of hygienic macro expansion through the use of explicit substitutions instead of conventional renaming techniques. The semantics also includes the formal description of Macro Scheme, the meta-language used for evaluating computational macros. Zusammenfassung Es ist m¨oglich, eine formale Semantik anzugeben, welche die Phasen Konfiguration, syntak- tische Analyse mit Makroexpansion, Linken und Auswertung fur¨ ein vollparametrisiertes Mo- dulsystem mit Modulen als Werten erster Klasse, unabh¨angiger Ubersetzung¨ und Code-Sharing beschreibt.
    [Show full text]
  • Foreign-Function Interfaces for Garbage-Collected Programming Languages
    Foreign-Function Interfaces for Garbage-Collected Programming Languages Marcus Crestani Eberhard-Karls-Universitat¨ Tubingen¨ [email protected] Abstract Programs in high-level, garbage-collected programming languages often need to access libraries that are written in other programming languages. A foreign-function interface provides a high-level lan- guage with access to low-level programming languages and negoti- ates between the inside and the outside world by taking care of the High-Level Foreign low-level details. In this paper, I provide an overview of what differ- Programming Function External Code ent kinds of foreign-function interfaces are in use in today’s imple- Language Interface mentations of functional programming languages to help decide on the design of a new foreign-function interface for Scheme 48. I have revised several mechanisms and design ideas and compared them on usability, portability, memory consumption and thread safety. I discuss the garbage-collection related parts of foreign-function in- terfaces using Scheme as the high-level functional language and C as the external language. Figure 1. Foreign-function interface 1. Introduction Programs in functional programming languages often need to ac- This paper reflects my survey, summarizes the results, and presents cess libraries that are written in other programming languages. Scheme 48’s new foreign-function interface, which will replace the Back in 1996, Scheme 48 [10] received its first foreign-function current one in the near future. interface. Over the years, developers connected many external li- braries to Scheme 48 using this foreign-function interface. Many 1.1 Foreign-Function Interfaces other Scheme implementations use a similar foreign-function in- A foreign-function interface provides a high-level programming terface, for example Elk [12], scsh [18], and PLT Scheme’s static language with access to other (usually low-level) programming lan- foreign interface [6].
    [Show full text]
  • Functional Package Management with Guix
    Functional Package Management with Guix Ludovic Courtès Bordeaux, France [email protected] ABSTRACT 1. INTRODUCTION We describe the design and implementation of GNU Guix, a GNU Guix1 is a purely functional package manager for the purely functional package manager designed to support a com- GNU system [20], and in particular GNU/Linux. Pack- plete GNU/Linux distribution. Guix supports transactional age management consists in all the activities that relate upgrades and roll-backs, unprivileged package management, to building packages from source, honoring the build-time per-user profiles, and garbage collection. It builds upon the and run-time dependencies on packages, installing, removing, low-level build and deployment layer of the Nix package man- and upgrading packages in user environments. In addition ager. Guix uses Scheme as its programming interface. In to these standard features, Guix supports transactional up- particular, we devise an embedded domain-specific language grades and roll-backs, unprivileged package management, (EDSL) to describe and compose packages. We demonstrate per-user profiles, and garbage collection. Guix comes with a how it allows us to benefit from the host general-purpose distribution of user-land free software packages. programming language while not compromising on expres- siveness. Second, we show the use of Scheme to write build Guix seeks to empower users in several ways: by offering the programs, leading to a \two-tier" programming system. uncommon features listed above, by providing the tools that allow users to formally correlate a binary package and the Categories and Subject Descriptors \recipes" and source code that led to it|furthering the spirit D.4.5 [Operating Systems]: Reliability; D.4.5 [Operating of the GNU General Public License|, by allowing them to Systems]: System Programs and Utilities; D.1.1 [Software]: customize the distribution, and by lowering the barrier to Applicative (Functional) Programming entry in distribution development.
    [Show full text]
  • A Tractable Scheme Implementation
    LISP AND SYMBOLIC COMPUTATION:An International Journal, 7, 315-335 (1994) © 1994 Kluwer Academic Publishers, Boston. Manufactured in The Netherlands. A Tractable Scheme Implementation RICHARD A. KELSEY [email protected] NEC Research Institute JONATHAN A. REES [email protected] M1T and Cornell University Abstract. Scheme 48 is an implementation of the Scheme programming language constructed with tractability and reliability as its primary design goals. It has the structural properties of large, compiler-based Lisp implementations: it is written entirely in Scheme, is bootstrapped via its compiler, and provides numerous language extensions. It controls the complexity that ordinarily attends such large Lisp implementations through clear articulation of internal modularity and by the exclusion of features, optimizations, and generalizations that are of only marginal value. Keywords: byte-code interpreters, virtual machines, modularity, Scheme, partial evaluation, layered design 1. Introduction Scheme 48 is an implementation of the Scheme programming language constructed with tractability and reliability as its primary design goals. By tractability we mean the ease with which the system can be understood and changed. Although Lisp dialects, including Scheme, are relatively simple languages, implementation tractability is often threatened by the demands of providing high performance and extended functionality. The Scheme 48 project was initiated in order to experiment with techniques for main- taining implementation tractability in the face of countervailing pressures and to find out what tradeoffs were involved in doing so. (The project was originally an experiment to see if a Scheme implementation could be written in a single weekend; the 48 refers to forty-eight hours.) Small Lisp implementations are usually tractable merely by virtue of being small; it is usually possible for an experienced programmer to read and understand the entire source program in a few days.
    [Show full text]
  • The Incomplete Scheme 48 Reference Manual for Release 1.8
    The Incomplete Scheme 48 Reference Manual for release 1.8 Richard Kelsey Jonathan Rees Mike Sperber A line may take us hours, yet if it does not seem a moment’s thought All our stitching and unstitching has been as nought. Yeats Adam’s Curse ii Acknowledgements Thanks to Scheme 48’s users for their suggestions, bug reports, and forbearance. Thanks also to Deborah Tatar for providing the Yeats quotation. iii Contents Contents iv 1 Introduction 1 2 User’s guide 2 2.1 Command line arguments . 2 2.2 Command processor . 3 2.3 Editing . 3 2.4 Performance . 3 2.5 Disassembler . 4 2.6 Module system . 4 2.7 Library . 6 3 Command processor 7 3.1 Current focus value and ## ..................... 7 3.2 Command levels . 8 3.3 Logistical commands . 9 3.4 Module commands . 9 3.5 Debugging commands . 9 3.6 Settings . 11 3.7 Inspection mode . 13 3.8 Command programs . 14 3.9 Building images . 15 3.10 Resource query and control . 15 3.11 Threads . 16 3.12 Quite obscure . 17 4 Module system 18 4.1 Introduction . 18 4.2 The configuration language . 19 4.3 Interfaces . 21 4.4 Macros . 22 4.5 Higher-order modules . 23 4.6 Compiling and linking . 23 iv 4.7 Semantics of configuration mutation . 23 4.8 Command processor support . 24 4.9 Configuration packages . 27 4.10 Discussion . 28 5 Libraries 30 5.1 General utilities . 30 5.2 Pretty-printing . 32 5.3 Bitwise integer operations . 32 5.4 Byte vectors .
    [Show full text]
  • A Universal Scripting Framework Or Lambda: the Ultimate “Little Language”
    A Universal Scripting Framework or Lambda: the ultimate “little language” Olin Shivers MIT AI Lab, Cambridge, Mass. 02139, USA Abstract. The “little languages” approach to systems programming is flawed: inefficient, fragile, error-prone, inexpressive, and difficult to compose. A bet- ter solution is to embed task-specific sublanguages within a powerful, syntac- tically extensible, universal language, such as Scheme. I demonstrate two such embeddings that have been implemented in scsh, a Scheme programming envi- ronment for Unix systems programming. The first embedded language is a high- level process-control notation; the second provides for Awk-like processing. Em- bedding systems in this way is a powerful technique: for example, although the embedded Awk system was implemented with 7% of the code required for the standard C-based Awk, it is significantly more expressive than its C counterpart. 1 Introduction Many programming tools are built around the idea of “little languages”—small inter- preters implementing a programming language that has been tuned to the specifics of some specialised task domain. This approach to systems-building was popularised by Unix, which provides a host of little-language processors. For example, the following Unix language interpreters all support notations tuned for specialised task domains: Task Interpreter regular-expression based string transforms sed pattern-matching awk type-setting nroff/tbl/eqn dependency-directed recompilation make file-system tree-walking find program invocation and composition sh Little languages complement the Unix “toolkit” philosophy—the operating system provides mechanisms for composing little-language based components into larger sys- tems (and, in fact, the principal interface for doing so is itself a little language, the shell).
    [Show full text]
  • [Special-PDF] Olin Shivers Scsh Manual High School
    Olin Shivers Scsh Manual High School Download Olin Shivers Scsh Manual High School Iain Ferguson, Edward Martin and Burt Kaufman. Foreword by Daniel Friedman. "The Schemer's Guide: Second Edition" Schemers Inc, Ft. Lauderdale, FL, 1995. (see EdScheme entry in [2-2]) 330 pages, ISBN 0-9628745-2- 3, $35.95. This book assumes no previous programming experience and is ideal for high school or college students. Olin Shivers’ Acknowledgements to the Scsh Reference Manual: Who should I thank? My so-called “colleagues,” who laugh at me behind my back, all the while becoming famous on my work? My worthless graduate students, whose computer skills appear to be limited to downloading bitmaps off of netnews? 8 May 2006. Olin Shivers, Brian D. Carlstrom, Martin Gasbichler, and Mike Sperber. Around with computers,'' go to med school, and become a radiologist? In Allegro CL 4.1 [SPARC; R1], the rule of thumb is that for less than 24 elements, linear search using alists beats hashing. In Lucid CL 4.0.1 HP 9000-700, the break-even point is at 10 elements. The break-even points vary in other lisps from as low as 4 elements to as high as 100 elements. Scsh is limited to 32-bit platforms but there is a development version against the latest Scheme 48 that works in 64-bit mode. It is free and open-source software released under a BSD license. Features. Scsh includes these notable features: Library support for list, character, and string manipulations; A copy of the 1983-84 high school football, volleyball and basketball schedules.
    [Show full text]
  • Contracts Be Misunderstood (Functional Pearl)
    Oh Lord, Please Don’t Let Contracts Be Misunderstood (Functional Pearl) Christos Dimoulas, Max S. New, Robert Bruce Findler, Matthias Felleisen PLT, USA {chrdimo,maxsnew,robby,matthias}@racket-lang.org Abstract gramming language to not only express logical assertions about Contracts feel misunderstood, especially those with a higher-order their functions but also construct new forms of contracts with soul. While software engineers appreciate contracts as tools for ar- user-defined combinators. Especially in the context of languages ticulating the interface between components, functional program- that shout “domain specific languages” from every roof top—say mers desperately search for their types and meaning, completely Racket—researchers and developers ought to be able to eliminate the problems that plague sophisticated practical applications of forgetting about their pragmatics. 1 This gem presents a novel analysis of contract systems. Applied conventional contract systems. If they put their mind to it, they to the higher-order kind, this analysis reveals their large and clearly could construct linguistic mechanisms that raised the level of ex- unappreciated software engineering potential. Three sample appli- pressiveness and allowed programmers to articulate an unprece- cations illustrate where this kind of exploration may lead. dented detail of precision for a relatively low cost in terms of code. This gem demonstrates how this alternative mind set about con- Categories and Subject Descriptors D.3.3 [Programming Lan- tracts opens new possibilities. It starts with a novel conceptual guages]: Language Constructs and Features analysis of contracts, re-imagining them as an interlocking sys- tem of interposition points, linguistic constructs for contract attach- Keywords Contracts, Specifications, Language design ment, and DSLs for assembling logical assertions from rather sim- ple building blocks (section 2).
    [Show full text]