Author: yamakenz
Date: Sun Jul 22 15:06:27 2007
New Revision: 4782
Added:
sigscheme-trunk/lib/srfi-9.scm
- copied, changed from r4781, /vendor/misc/srfi-9.html
Log:
* lib/srfi-9.scm
- New file copied from vendor/misc/srfi-9.html
- Trim the reference implementation code in the HTML
Copied: sigscheme-trunk/lib/srfi-9.scm (from r4781, /vendor/misc/srfi-9.html)
==============================================================================
--- /vendor/misc/srfi-9.html (original)
+++ sigscheme-trunk/lib/srfi-9.scm Sun Jul 22 15:06:27 2007
@@ -1,169 +1,20 @@
-<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 3.2//EN">
-<html>
- <head>
- <title>SRFI 9: Defining Record Types</title>
- </head>
-
- <body>
-
-<H1>Title</H1>
-
-Defining Record Types
-
-<H1>Author</H1>
-
-Richard Kelsey
-
-<H1>Status</H1>
-
-This SRFI is currently in ``final'' status. To see an explanation of each
status that a SRFI can hold, see <A
HREF="http://srfi.schemers.org/srfi-process.html";>here</A>.
-You can access the discussion via <A
HREF="http://srfi.schemers.org/srfi-9/mail-archive/maillist.html";>the archive
of the mailing list</A>.
-<P><UL>
-<LI>Received: 1999/07/01
-<LI>Revised: 1999/08/25
-<LI>Draft: 1999/07/07-1999/09/06
-<LI>Final: 1999/09/09
-</UL>
-
-<H1>Abstract</H1>
-
-This SRFI describes syntax for creating new data types, called record types.
-A predicate, constructor, and field accessors and modifiers are defined for
-each record type. Each new record type is distinct from all existing types,
-including other record types and Scheme's predefined types.
-
-<H1>Rationale</H1>
-
-Many Scheme implementations provide means for creating new types,
- usually called either records or structures.
-The <code>DEFINE-RECORD-TYPE</code> syntax described here is a slight
- simplification of one written for Scheme 48 by Jonathan Rees.
-Unlike many record-defining macros or special forms, it
- does not create any new identifiers.
-Instead, the names of the
- record type, predicate, constructor, and so on are all listed explicitly
- in the source.
-This has the following advantages:
-<UL>
-<LI> It can be defined using a simple <code>SYNTAX-RULES</code> macro
- in Scheme implementations that provide a procedural interface
- for creating record types.
-<LI> It does not restrict users to a particular naming convention.
-<LI> Tools like <code>grep</code> and GNU Emacs's tag facility will see the
- defining occurance of each identifier.
-</UL>
-
-<H1>Specification</H1>
-
-The syntax of a record-type definition is:
-
-<PRE>
- <command or definition>
- -> <record type definition> ; addition to 8.1.6 in R5RS
-
- <record type definition>
- -> (define-record-type <type name>
- (<constructor name> <field tag> ...)
- <predicate name>
- <field spec> ...)
-
- <field spec> -> (<field tag> <accessor name>)
- -> (<field tag> <accessor name> <modifier
name>)
-
- <field tag> -> <identifier>
- <... name> -> <identifier>
-</PRE>
-
-<code>DEFINE-RECORD-TYPE</code> is generative:
-each use creates a new record type that is distinct from all existing types,
-including other record types and Scheme's predefined types.
-
-Record-type definitions may only occur at top-level (there are two
-possible semantics for `internal' record-type definitions, generative
-and nongenerative, and no consensus as to which is better).
-
-<P>
-An instance of <code>DEFINE-RECORD-TYPE</code> is equivalent to the following
-definitions:
-<UL>
-<LI> <code><type name></code> is bound to a representation of the record
- type itself. Operations on record types, such as defining print
- methods, reflection, etc. are left to other SRFIs.
-
-<LI> <code><constructor name></code> is bound to a procedure that takes
- as many arguments as there are <code><field tag></code>s in the
- <code>(<constructor name> ...)</code>
- subform and returns a new <code><type name></code> record.
- Fields whose tags are listed with <code><constructor name></code>
- have the corresponding argument as their
- initial value. The initial values of all other fields are unspecified.
-
-<LI> <code><predicate name></code> is a predicate that returns #T when
- given a value returned by <code><constructor name></code> and #F
- for everything else.
-
-<LI> Each <code><accessor name></code> is a procedure that takes a record
- of type <code><type name></code> and returns the current value of the
- corresponding field.
- It is an error to pass an accessor a value which is not a record of
- the appropriate type.
-
-<LI> Each <code><modifier name></code> is a procedure that takes a record
- of type <code><type name></code> and a value which becomes the new
- value of the corresponding field; an unspecified value is returned.
- It is an error to pass a modifier a first
- argument which is not a record of the appropriate type.
-</UL>
-
-<P>
-Records are disjoint from the types listed in Section 4.2 of R5RS.
-
-<P>
-<code>Set!</code>ing the value of any of these identifiers has no
- effect on the behavior of any of their original values.
-
-<P>
-The following
-<PRE>
- (define-record-type :pare
- (kons x y)
- pare?
- (x kar set-kar!)
- (y kdr))
-</PRE>
-defines <code>KONS</code> to be a constructor, <code>KAR</code> and
-<code>KDR</code> to be accessors, <code>SET-KAR!</code> to be a modifier,
-and <code>PARE?</code> to be a predicate for <code>:PARE</code>s.
-
-<PRE>
- (pare? (kons 1 2)) --> #t
- (pare? (cons 1 2)) --> #f
- (kar (kons 1 2)) --> 1
- (kdr (kons 1 2)) --> 2
- (let ((k (kons 1 2)))
- (set-kar! k 3)
- (kar k)) --> 3
-</PRE>
-
-<H1>Implementation</H1>
-
-This code is divided into three layers. In top-down order these are:
-<OL>
-<LI> Syntax definitions for <code>DEFINE-RECORD-TYPE</code> and an auxillary
- macro.
-<LI> An implementation of record types with a procedural interface.
-Some Scheme implementations already have something close to this.
-<LI> Vector-like records implemented in R5RS. This redefines some standard
-Scheme procedures and therefor must be loaded before any other code, including
-part 2 above. Note that these procedures can be used to break the
-record-type abstraction (for example, <code>RECORD-SET!</code> can be used
-to modify the type of a record). Access to these procedures should be
-restricted.
-</OL>
+;; This code is divided into three layers. In top-down order these are:
+;;
+;; 1. Syntax definitions for DEFINE-RECORD-TYPE and an auxillary macro.
+;; 2. An implementation of record types with a procedural interface. Some
+;; Scheme implementations already have something close to this.
+;; 3. Vector-like records implemented in R5RS. This redefines some standard
+;; Scheme procedures and therefor must be loaded before any other code,
+;; including part 2 above. Note that these procedures can be used to
+;; break the record-type abstraction (for example, RECORD-SET! can be
+;; used to modify the type of a record). Access to these procedures
+;; should be restricted.
+
+
+;;
+;; Syntax definitions
+;;
-<H2>Syntax definitions</H2>
-
-<PRE>
; Definition of DEFINE-RECORD-TYPE
(define-syntax define-record-type
@@ -193,23 +44,24 @@
(begin
(define accessor (record-accessor type 'field-tag))
(define modifier (record-modifier type 'field-tag))))))
-</PRE>
-<H2>Record types</H2>
-<PRE>
+;;
+;; Record types
+;;
+
; We define the following procedures:
;
-; (make-record-type <type-name <field-names>) ->
<record-type>
-; (record-constructor <record-type<field-names>) ->
<constructor>
-; (record-predicate <record-type>) -> <predicate>
-; (record-accessor <record-type <field-name>) -> <accessor>
-; (record-modifier <record-type <field-name>) -> <modifier>
+; (make-record-type <type-name> <field-names>) -> <record-type>
+; (record-constructor <record-type> <field-names>) -> <constructor>
+; (record-predicate <record-type>) -> <predicate>
+; (record-accessor <record-type <field-name>) -> <accessor>
+; (record-modifier <record-type <field-name>) -> <modifier>
; where
-; (<constructor> <initial-value> ...) -> <record>
-; (<predicate> <value>) -> <boolean>
-; (<accessor> <record>) -> <value>
-; (<modifier> <record> <value>) -> <unspecific>
+; (<constructor> <initial-value> ...) -> <record>
+; (<predicate> <value>) -> <boolean>
+; (<accessor> <record>) -> <value>
+; (<modifier> <record> <value>) -> <unspecific>
; Record types are implemented using vector-like records. The first
; slot of each record contains the record's type, which is itself a
@@ -308,19 +160,20 @@
type))
(record-set! thing index value)
(error "modifier applied to bad value" type tag thing)))))
-</PRE>
-<H2>Records</H2>
-<PRE>
+;;
+;; Records
+;;
+
; This implements a record abstraction that is identical to vectors,
; except that they are not vectors (VECTOR? returns false when given a
; record and RECORD? returns false when given a vector). The following
; procedures are provided:
-; (record? <value>) -> <boolean>
-; (make-record <size>) -> <record>
-; (record-ref <record> <index>) -> <value>
-; (record-set! <record> <index> <value>) ->
<unspecific>
+; (record? <value>) -> <boolean>
+; (make-record <size>) -> <record>
+; (record-ref <record> <index>) -> <value>
+; (record-set! <record> <index> <value>) -> <unspecific>
;
; These can implemented in R5RS Scheme as vectors with a distinguishing
; value at index zero, providing VECTOR? is redefined to be a procedure
@@ -352,7 +205,7 @@
(define (record? x)
(and (real-vector? x)
- (< 0 (vector-length x))
+ (< 0 (vector-length x))
(eq? (vector-ref x 0)
record-marker)))
@@ -366,38 +219,25 @@
(define (record-set! record index value)
(vector-set! record (+ index 1) value))
-</PRE>
-
-<H1>Copyright</H1>
-
-<p>Copyright (C) Richard Kelsey (1999). All Rights Reserved. </p>
-
-<p>
-Permission is hereby granted, free of charge, to any person obtaining
-a copy of this software and associated documentation files (the
-"Software"), to deal in the Software without restriction, including
-without limitation the rights to use, copy, modify, merge, publish,
-distribute, sublicense, and/or sell copies of the Software, and to
-permit persons to whom the Software is furnished to do so, subject to
-the following conditions:
-</p>
-<p>
-The above copyright notice and this permission notice shall be
-included in all copies or substantial portions of the Software.
-</p>
-<p>
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
-EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
-NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
-LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
-OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
-WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-</p>
-
-<hr>
- <address>Editor: <a href="mailto:srfi-editors at srfi dot schemers dot
org">Mike Sperber</a></address>
- </body>
-</html>
+;; Copyright (C) Richard Kelsey (1999). All Rights Reserved.
+;;
+;; Permission is hereby granted, free of charge, to any person obtaining
+;; a copy of this software and associated documentation files (the
+;; "Software"), to deal in the Software without restriction, including
+;; without limitation the rights to use, copy, modify, merge, publish,
+;; distribute, sublicense, and/or sell copies of the Software, and to
+;; permit persons to whom the Software is furnished to do so, subject to
+;; the following conditions:
+;;
+;; The above copyright notice and this permission notice shall be
+;; included in all copies or substantial portions of the Software.
+;;
+;; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+;; EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+;; MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+;; NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+;; LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+;; OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+;; WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
