From 8ffbc2df0fde83082610149d24e594c1cd879f4a Mon Sep 17 00:00:00 2001
From: Bryan Newbold <bnewbold@robocracy.org>
Date: Mon, 20 Feb 2017 00:05:25 -0800
Subject: Import Upstream version 2a6

---
 structure.scm | 80 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)
 create mode 100644 structure.scm

(limited to 'structure.scm')

diff --git a/structure.scm b/structure.scm
new file mode 100644
index 0000000..0d379b9
--- /dev/null
+++ b/structure.scm
@@ -0,0 +1,80 @@
+;;; "structure.scm" syntax-case structure macros
+;;; Copyright (C) 1992 R. Kent Dybvig
+;;;
+;;; Permission to copy this software, in whole or in part, to use this
+;;; software for any lawful purpose, and to redistribute this software
+;;; is granted subject to the restriction that all copies made of this
+;;; software must include this copyright notice in full.  This software
+;;; is provided AS IS, with NO WARRANTY, EITHER EXPRESS OR IMPLIED,
+;;; INCLUDING BUT NOT LIMITED TO IMPLIED WARRANTIES OF MERCHANTABILITY
+;;; OR FITNESS FOR ANY PARTICULAR PURPOSE.  IN NO EVENT SHALL THE
+;;; AUTHORS BE LIABLE FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES OF ANY
+;;; NATURE WHATSOEVER.
+
+;;; Written by Robert Hieb & Kent Dybvig
+
+;;; This file was munged by a simple minded sed script since it left
+;;; its original authors' hands.  See syncase.sh for the horrid details.
+
+;;; structure.ss
+;;; Robert Hieb & Kent Dybvig
+;;; 92/06/18
+
+(define-syntax define-structure
+  (lambda (x)
+     (define construct-name
+	(lambda (template-identifier . args)
+	   (implicit-identifier
+	      template-identifier
+	      (string->symbol
+		 (apply string-append
+			(map (lambda (x)
+				(if (string? x)
+				    x
+				    (symbol->string (syntax-object->datum x))))
+			     args))))))
+     (syntax-case x ()
+	((_ (name id1 ...))
+	 (syntax (define-structure (name id1 ...) ())))
+	((_ (name id1 ...) ((id2 init) ...))
+	 (with-syntax
+	    ((constructor (construct-name (syntax name) "make-" (syntax name)))
+	     (predicate (construct-name (syntax name) (syntax name) "?"))
+	     ((access ...)
+	      (map (lambda (x) (construct-name x (syntax name) "-" x))
+		   (syntax (id1 ... id2 ...))))
+	     ((assign ...)
+	      (map (lambda (x)
+		      (construct-name x "set-" (syntax name) "-" x "!"))
+		   (syntax (id1 ... id2 ...))))
+	     (structure-length
+	      (+ (length (syntax (id1 ... id2 ...))) 1))
+	     ((index ...)
+	      (let f ((i 1) (ids (syntax (id1 ... id2 ...))))
+		 (if (null? ids)
+		     '()
+		     (cons i (f (+ i 1) (cdr ids)))))))
+	    (syntax (begin
+		       (define constructor
+			  (lambda (id1 ...)
+			     (let* ((id2 init) ...)
+				(vector 'name id1 ... id2 ...))))
+		       (define predicate
+			  (lambda (x)
+			     (and (vector? x)
+				  (= (vector-length x) structure-length)
+				  (eq? (vector-ref x 0) 'name))))
+		       (define access
+			  (lambda (x)
+			     (vector-ref x index)))
+		       ...
+		       ;; define macro accessors this way:
+		       ;; (define-syntax access
+		       ;;       (syntax-case x ()
+		       ;;          ((_ x)
+		       ;;           (syntax (vector-ref x index)))))
+		       ;; ...
+		       (define assign
+			  (lambda (x update)
+			     (vector-set! x index update)))
+		       ...)))))))
-- 
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