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+;;;; Implementation of VICINITY and MODULES for Scheme
+;Copyright (C) 1991, 1992, 1993, 1994 Aubrey Jaffer
+;
+;Permission to copy this software, to redistribute it, and to use it
+;for any purpose is granted, subject to the following restrictions and
+;understandings.
+;
+;1.  Any copy made of this software must include this copyright notice
+;in full.
+;
+;2.  I have made no warrantee or representation that the operation of
+;this software will be error-free, and I am under no obligation to
+;provide any services, by way of maintenance, update, or otherwise.
+;
+;3.  In conjunction with products arising from the use of this
+;material, there shall be no use of my name in any advertising,
+;promotional, or sales literature without prior written consent in
+;each case.
+
+(define *SLIB-VERSION* "2a6")
+
+;;; Standardize msdos -> ms-dos.
+(define software-type
+  (cond ((eq? 'msdos (software-type))
+	 (lambda () 'ms-dos))
+	(else software-type)))
+
+(define (user-vicinity)
+  (case (software-type)
+    ((VMS)	"[.]")
+    (else	"")))
+
+(define program-vicinity
+  (let ((*vicinity-suffix*
+	 (case (software-type)
+	   ((AMIGA)	'(#\: #\/))
+	   ((MS-DOS WINDOWS ATARIST OS/2)	'(#\\ #\/))
+	   ((MACOS THINKC)	'(#\:))
+	   ((NOSVE)	'(#\: #\.))
+	   ((UNIX COHERENT)	'(#\/))
+	   ((VMS)	'(#\: #\])))))
+    (lambda ()
+      (let loop ((i (- (string-length *load-pathname*) 1)))
+	(cond ((negative? i) "")
+	      ((memv (string-ref *load-pathname* i) *vicinity-suffix*)
+	       (substring *load-pathname* 0 (+ i 1)))
+	      (else (loop (- i 1))))))))
+
+(define sub-vicinity
+  (case (software-type)
+    ((VMS)
+     (lambda
+      (vic name)
+      (let ((l (string-length vic)))
+	(if (or (zero? (string-length vic))
+		(not (char=? #\] (string-ref vic (- l 1)))))
+	    (string-append vic "[" name "]")
+	    (string-append (substring vic 0 (- l 1))
+			   "." name "]")))))
+    (else
+     (let ((*vicinity-suffix*
+	    (case (software-type)
+	      ((NOSVE) ".")
+	      ((UNIX COHERENT AMIGA) "/")
+	      ((MACOS THINKC) ":")
+	      ((MS-DOS WINDOWS ATARIST OS/2) "\\"))))
+       (lambda (vic name)
+	 (string-append vic name *vicinity-suffix*))))))
+
+(define (make-vicinity <pathname>) <pathname>)
+
+(define *catalog*
+  (map
+   (lambda (p)
+     (if (symbol? (cdr p)) p
+	 (cons
+	  (car p)
+	  (if (pair? (cdr p))
+	      (cons 
+	       (cadr p)
+	       (in-vicinity (library-vicinity) (cddr p)))
+	      (in-vicinity (library-vicinity) (cdr p))))))
+   '(
+     (rev4-optional-procedures	.	"sc4opt")
+     (rev2-procedures		.	"sc2")
+     (multiarg/and-		.	"mularg")
+     (multiarg-apply		.	"mulapply")
+     (rationalize		.	"ratize")
+     (transcript		.	"trnscrpt")
+     (with-file			.	"withfile")
+     (dynamic-wind		.	"dynwind")
+     (dynamic			.	"dynamic")
+     (fluid-let		macro	.	"fluidlet")
+     (alist			.	"alist")
+     (hash			.	"hash")
+     (sierpinski		.	"sierpinski")
+     (soundex			.	"soundex")
+     (hash-table		.	"hashtab")
+     (logical			.	"logical")
+     (random			.	"random")
+     (random-inexact		.	"randinex")
+     (modular			.	"modular")
+     (primes			.	"primes")
+     (factor			.	"factor")
+     (charplot			.	"charplot")
+     (sort			.	"sort")
+     (tsort			.	topological-sort)
+     (topological-sort		.	"tsort")
+     (common-list-functions	.	"comlist")
+     (tree			.	"tree")
+     (format			.	"format")
+     (format-inexact		.	"formatfl")
+     (generic-write		.	"genwrite")
+     (pretty-print		.	"pp")
+     (pprint-file		.	"ppfile")
+     (object->string		.	"obj2str")
+     (string-case		.	"strcase")
+     (stdio			.	"stdio")
+     (printf			.	"printf")
+     (scanf			.	"scanf")
+     (line-i/o			.	"lineio")
+     (string-port		.	"strport")
+     (getopt			.	"getopt")
+     (debug			.	"debug")
+     (qp			.	"qp")
+     (break	defmacro	.	"break")
+     (trace	defmacro	.	"trace")
+;     (eval			.	"eval")
+     (record			.	"record")
+     (promise			.	"promise")
+     (synchk			.	"synchk")
+     (defmacroexpand		.	"defmacex")
+     (macro-by-example	defmacro	.	"mbe")
+     (syntax-case		.	"scainit")
+     (syntactic-closures	.	"scmacro")
+     (macros-that-work		.	"macwork")
+     (macro			.	macros-that-work)
+     (object			.	"object")
+     (record-object		.	"recobj")
+     (yasos		macro	.	"yasyn")
+     (oop			.	yasos)
+     (collect		macro	.	"collect")
+     (struct	defmacro	.	"struct")
+     (structure	syntax-case	.	"structure")
+     (values			.	"values")
+     (queue			.	"queue")
+     (priority-queue		.	"priorque")
+     (array			.	"array")
+     (array-for-each		.	"arraymap")
+     (repl			.	"repl")
+     (process			.	"process")
+     (chapter-order		.	"chap")
+     (posix-time		.	"time")
+     (common-lisp-time		.	"cltime")
+     (relational-database	.	"rdms")
+     (database-utilities	.	"dbutil")
+     (database-browse		.	"dbrowse")
+     (alist-table		.	"alistab")
+     (parameters		.	"paramlst")
+     (read-command		.	"comparse")
+     (batch			.	"batch")
+     (make-crc			.	"makcrc")
+     (wt-tree			.	"wttree")
+     (string-search		.	"strsrch")
+     (root			.	"root")
+     )))
+
+(set! *catalog*
+      (append (list
+	       (cons 'schelog
+		     (in-vicinity (sub-vicinity (library-vicinity) "schelog")
+				  "schelog"))
+	       (cons 'portable-scheme-debugger
+		     (in-vicinity (sub-vicinity (library-vicinity) "psd")
+				  "psd-slib")))
+	      *catalog*))
+
+(define *load-pathname* #f)
+
+(define (slib:pathnameize-load *old-load*)
+  (lambda (<pathname> . extra)
+    (let ((old-load-pathname *load-pathname*))
+      (set! *load-pathname* <pathname>)
+      (apply *old-load* (cons <pathname> extra))
+      (require:provide <pathname>)
+      (set! *load-pathname* old-load-pathname))))
+
+(set! slib:load-source
+      (slib:pathnameize-load slib:load-source))
+(set! slib:load
+      (slib:pathnameize-load slib:load))
+
+;;;; MODULES
+
+(define *modules* '())
+
+(define (require:provided? feature)
+  (if (symbol? feature)
+      (if (memq feature *features*) #t
+	  (let ((path (cdr (or (assq feature *catalog*) '(#f . #f)))))
+	    (cond ((symbol? path) (provided? path))
+		  ((member (if (pair? path) (cdr path) path) *modules*)
+		   #t)
+		  (else #f))))
+      (and (member feature *modules*) #t)))
+
+(define (require:feature->path feature)
+  (if (symbol? feature)
+      (let ((path (cdr (or (assq feature *catalog*) '(#f . #f)))))
+	(if (symbol? path) (require:feature->path path) path))
+      feature))
+
+(define (require:require feature)
+  (or (require:provided? feature)
+      (let ((path (require:feature->path feature)))
+	(cond ((and (not path) (string? feature) (file-exists? feature))
+	       (set! path feature)))
+	(cond ((not path)
+	       ;;(newline) (display ";required feature not supported: ")
+	       ;;(display feature) (newline)
+	       (slib:error ";required feature not supported: " feature))
+	      ((not (pair? path))	;simple name
+	       (slib:load path)
+	       (require:provide feature))
+	      (else			;special loads
+	       (require (car path))
+	       (apply (case (car path)
+			((macro) macro:load)
+			((syntactic-closures) synclo:load)
+			((syntax-case) syncase:load)
+			((macros-that-work) macwork:load)
+			((macro-by-example) defmacro:load)
+			((defmacro) defmacro:load)
+			((source) slib:load-source)
+			((compiled) slib:load-compiled))
+		      (if (list? path) (cdr path) (list (cdr path))))
+	       (require:provide feature))))))
+
+(define (require:provide feature)
+  (if (symbol? feature)
+      (if (not (memq feature *features*))
+	  (set! *features* (cons feature *features*)))
+      (if (not (member feature *modules*))
+	  (set! *modules* (cons feature *modules*)))))
+
+(require:provide 'vicinity)
+
+(define provide require:provide)
+(define provided? require:provided?)
+(define require require:require)
+
+;;; Supported by all implementations
+(provide 'eval)
+(provide 'defmacro)
+
+(if (and (string->number "0.0") (inexact? (string->number "0.0")))
+    (provide 'inexact))
+(if (rational? (string->number "1/19")) (provide 'rational))
+(if (real? (string->number "0.0")) (provide 'real))
+(if (complex? (string->number "1+i")) (provide 'complex))
+(let ((n (string->number "9999999999999999999999999999999")))
+  (if (and n (exact? n)) (provide 'bignum)))
+
+(define current-time
+  (if (provided? 'current-time) current-time
+      (let ((c 0))
+	(lambda () (set! c (+ c 1)) c))))
+(define difftime (if (provided? 'current-time) difftime -))
+(define offset-time (if (provided? 'current-time) offset-time +))
+
+(define report:print
+  (lambda args
+    (for-each (lambda (x) (write x) (display #\ )) args)
+    (newline)))
+
+(define slib:report
+  (let ((slib:report (lambda () (slib:report-version) (slib:report-locations))))
+    (lambda args
+      (cond ((null? args) (slib:report))
+	    ((not (string? (car args)))
+	     (slib:report-version) (slib:report-locations #t))
+	    ((require:provided? 'transcript)
+	     (transcript-on (car args))
+	     (slib:report)
+	     (transcript-off))
+	    ((require:provided? 'with-file)
+	     (with-output-to-file (car args) slib:report))
+	    (else (slib:report))))))
+
+(define slib:report-version
+  (lambda ()
+    (report:print
+     'SLIB *SLIB-VERSION* 'on (scheme-implementation-type)
+     (scheme-implementation-version) 'on (software-type))))
+
+(define slib:report-locations
+  (let ((features *features*) (catalog *catalog*))
+    (lambda args
+      (report:print '(IMPLEMENTATION-VICINITY) 'is (implementation-vicinity))
+      (report:print '(LIBRARY-VICINITY) 'is (library-vicinity))
+      (report:print '(SCHEME-FILE-SUFFIX) 'is (scheme-file-suffix))
+      (cond (*load-pathname*
+	     (report:print '*LOAD-PATHNAME* 'is *load-pathname*)))
+      (cond ((not (null? *modules*))
+	     (report:print 'Loaded '*MODULES* 'are: *modules*)))
+      (let* ((i (+ -1 5)))
+	(cond ((eq? (car features) (car *features*)))
+	      (else (report:print 'loaded '*FEATURES* ':) (display slib:tab)))
+	(for-each
+	 (lambda (x)
+	   (cond ((eq? (car features) x)
+		  (if (not (eq? (car features) (car *features*))) (newline))
+		  (report:print 'Implementation '*FEATURES* ':)
+		  (display slib:tab) (set! i (+ -1 5)))
+		 ((zero? i) (newline) (display slib:tab) (set! i (+ -1 5)))
+		 ((not (= (+ -1 5) i)) (display #\ )))
+	   (write x) (set! i (+ -1 i)))
+	 *features*))
+      (newline)
+      (let* ((i #t))
+	(cond ((not (eq? (car catalog) (car *catalog*)))
+	       (report:print 'Additional '*CATALOG* ':)))
+	(cond ((or (pair? args) (not (eq? (car catalog) (car *catalog*))))
+	       (for-each
+		(lambda (x)
+		  (cond ((eq? (car catalog) x)
+			 (report:print 'Implementation '*CATALOG* ':)
+			 (set! i (pair? args))
+			 (cond (i)
+			       (else (display slib:tab) (report:print x)
+				     (display slib:tab) (report:print '...)))))
+		  (cond (i (display slib:tab) (report:print x))))
+		*catalog*))
+	      (else (report:print 'Implementation '*CATALOG* ':)
+		    (display slib:tab) (report:print (car *catalog*))
+		    (display slib:tab) (report:print '...))))
+      (newline))))
+
+(let ((sit (scheme-implementation-version)))
+  (cond ((zero? (string-length sit)))
+	((or (not (string? sit)) (char=? #\? (string-ref sit 0)))
+	 (newline)
+	 (slib:report-version)
+	 (report:print 'edit (scheme-implementation-type) ".init"
+		       'to 'set '(scheme-implementation-version) 'string)
+	 (report:print '(IMPLEMENTATION-VICINITY) 'is (implementation-vicinity))
+	 (report:print 'type '(slib:report) 'for 'configuration)
+	 (newline))))