path: root/require.scm

;;;; Implementation of VICINITY and MODULES for Scheme
;Copyright (C) 1991, 1992, 1993, 1994, 1997, 2002, 2003 Aubrey Jaffer
;
;Permission to copy this software, to modify it, to redistribute it,
;to distribute modified versions, 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 warranty 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* "3a1")
;@
(define (user-vicinity)
  (case (software-type)
    ((VMS)	"[.]")
    (else	"")))
;@
(define *load-pathname* #f)
;@
(define vicinity:suffix?
  (let ((suffi
	 (case (software-type)
	   ((AMIGA)				'(#\: #\/))
	   ((MACOS THINKC)			'(#\:))
	   ((MS-DOS WINDOWS ATARIST OS/2)	'(#\\ #\/))
	   ((NOSVE)				'(#\: #\.))
	   ((UNIX COHERENT PLAN9)		'(#\/))
	   ((VMS)				'(#\: #\])))))
    (lambda (chr) (and (memv chr suffi) #t))))
;@
(define (pathname->vicinity pathname)
  (let loop ((i (- (string-length pathname) 1)))
    (cond ((negative? i) "")
	  ((vicinity:suffix? (string-ref pathname i))
	   (substring pathname 0 (+ i 1)))
	  (else (loop (- i 1))))))
(define (program-vicinity)
  (if *load-pathname*
      (pathname->vicinity *load-pathname*)
      (slib:error 'program-vicinity " called; use slib:load to load")))
;@
(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) ".")
		   ((MACOS THINKC) ":")
		   ((MS-DOS WINDOWS ATARIST OS/2) "\\")
		   ((UNIX COHERENT PLAN9 AMIGA) "/"))))
	    (lambda (vic name)
	      (string-append vic name *vicinity-suffix*))))))
;@
(define (make-vicinity <pathname>) <pathname>)

(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))
      (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 *catalog* #f)
(define *base-table-implementations* '())
;@
(define (slib:version path)
  (let ((expr (and (file-exists? path)
		   (call-with-input-file path (lambda (port) (read port))))))
    (and (list? expr) (= 3 (length expr))
	 (eq? (car expr) 'define) (eq? (cadr expr) '*SLIB-VERSION*)
	 (string? (caddr expr)) (caddr expr))))

(define (catalog/require-version-match? slibcat)
  (let* ((apair (assq '*SLIB-VERSION* slibcat))
	 (req (in-vicinity (library-vicinity)
			   (string-append "require" (scheme-file-suffix))))
	 (reqvers (slib:version req)))
    (cond ((not (file-exists? req))
	   (slib:warn "can't find " req) #f)
	  ((not apair) #f)
	  ((not (equal? reqvers (cdr apair))) #f)
	  ((not (equal? reqvers *SLIB-VERSION*))
	   (slib:warn "The loaded " req " is stale.")
	   #t)
	  (else #t))))

(define (catalog:try-read vicinity name)
  (or (and vicinity name
	   (let ((path (in-vicinity vicinity name)))
	     (and (file-exists? path)
		  (call-with-input-file path
		    (lambda (port)
		      (do ((expr (read port) (read port))
			   (lst '() (cons expr lst)))
			  ((eof-object? expr)
			   (apply append lst))))))))
      '()))
;@
(define (catalog:resolve vicinity catlist)
  (define (res1 e) (if (string? e) (in-vicinity vicinity e) e))
  (define (resolve p)
    (cond ((symbol? (cdr p)) p)
	  ((not (list? p)) (cons (car p) (res1 (cdr p))))
	  ((null? (cddr p)) (cons (car p) (res1 (cadr p))))
	  (else (map res1 p))))
  (map resolve catlist))
;@
(define (catalog:read vicinity cat)
  (catalog:get #f)			; make sure *catalog* exists
  (set! *catalog*
	(append (catalog:resolve vicinity (catalog:try-read vicinity cat))
		*catalog*)))

(define (catalog:get feature)
  (if (not *catalog*)
      (let ((slibcat (catalog:try-read (implementation-vicinity) "slibcat")))
	(cond ((not (catalog/require-version-match? slibcat))
	       (slib:load (in-vicinity (library-vicinity) "mklibcat"))
	       (set! slibcat
		     (catalog:try-read (implementation-vicinity) "slibcat"))))
	(cond (slibcat
	       (set! *catalog* ((slib:eval
				 (cadr (or (assq 'catalog:filter slibcat)
					   '(#f identity))))
				slibcat))))
	(set! *catalog*
	      (append (catalog:try-read (home-vicinity) "homecat") *catalog*))
	(set! *catalog*
	      (append (catalog:try-read (user-vicinity) "usercat") *catalog*))))
  (and feature *catalog* (cdr (or (assq feature *catalog*) '(#f . #f)))))
;@
(define (slib:in-catalog? feature)
  (let ((path (catalog:get feature)))
    (if (symbol? path) (slib:in-catalog? path) path)))

;@
(define (feature-eval expression provided?)
  (define (bail expression)
    (slib:error 'invalid 'feature 'expression expression))
  (define (feval expression)
    (cond ((not expression) expression)
	  ((symbol? expression) (provided? expression))
	  ((and (list? expression) (pair? expression))
	   (case (car expression)
	     ((not) (case (length expression)
		      ((2) (not (feval (cadr expression))))
		      (else (bail expression))))
	     ((or)  (case (length expression)
		      ((1) #f)
		      ;;((2) (feval (cadr expression)))
		      (else (or (feval (cadr expression))
				(feval (cons 'or (cddr expression)))))))
	     ((and) (case (length expression)
		      ((1) #t)
		      ;;((2) (feval (cadr expression)))
		      (else (and (feval (cadr expression))
				 (feval (cons 'and (cddr expression)))))))
	     (else (bail expression))))
	  (else (bail expression))))
  (feval expression))
;@
(define (provided? expression)
  (define feature-list (cons (software-type) *features*))
  (define (provided? expression)
    (if (memq expression feature-list) #t
	(and *catalog*
	     (let ((path (catalog:get expression)))
	       (cond ((symbol? path) (provided? path))
		     (else #f))))))
  (feature-eval expression provided?))
;@
(define (require feature)
  (cond
   ((not feature) (set! *catalog* #f))
   ((slib:provided? feature))
   (else
    (let ((path (catalog:get feature)))
      (cond ((not path)
	     (slib:error 'slib:require 'unsupported 'feature feature))
	    ((symbol? path) (slib:provide feature) (slib:require path))
	    ((string? path)		;simple name
	     (and (not (eq? 'new-catalog feature)) (slib:provide feature))
	     (slib:load path))
	    (else			;dispatched loads
	     (slib:provide feature)
	     (slib: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)
		      ((aggregate)
		       (lambda feature (for-each slib:require feature)))
		      ((spectral-tristimulus-values) load-ciexyz)
		      ((color-names)
		       (lambda (filename)
			 (load-color-dictionary feature filename)))
		      (else (slib:error "unknown package loader" path)))
		    (if (list? path) (cdr path) (list (cdr path))))))))))
;@
(define (require-if feature? feature)
  (if (slib:provided? feature?) (slib:require feature)))
;@
(define (provide feature)
  (if (not (memq feature *features*))
      (set! *features* (cons feature *features*))))

;@
(define slib:provide provide)
(define slib:provided? provided?)
(define slib:require require)
(define slib:require-if require-if)
;;; Legacy
(define require:provide provide)
(define require:provided? provided?)
(define require:require require)

(slib:provide 'vicinity)
(if (and (string->number "0.0") (inexact? (string->number "0.0")))
    (slib:provide 'inexact))
(if (rational? (string->number "1/19")) (slib:provide 'rational))
(if (real? (string->number "0.0")) (slib:provide 'real))
(if (complex? (string->number "1+i")) (slib:provide 'complex))
(let ((n (string->number "9999999999999999999999999999999")))
  (if (and n (exact? n)) (slib:provide 'bignum)))

(cond
 ((slib:provided? 'srfi)
  (do ((idx 0 (+ 1 idx))
       (srfis (symbol->string 'srfi-)))
      ((> idx 100))
    (let ((srfi (string->symbol (string-append srfis (number->string idx)))))
      (if (slib:eval `(cond-expand (,srfi #t) (else #f)))
	  (slib:provide srfi))))))

(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))
	    ((slib:provided? 'transcript)
	     (transcript-on (car args))
	     (slib:report)
	     (transcript-off))
	    ((slib: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*))
    (lambda args
      (define sit (scheme-implementation-type))
      (define siv (string->symbol (scheme-implementation-version)))
      (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*)))
      (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 sit siv '*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)
      (report:print sit siv '*CATALOG* ':)
      (catalog:get #f)
      (cond ((pair? args)
	     (for-each (lambda (x) (display slib:tab) (report:print x))
		       *catalog*))
	    (else (display slib:tab) (report:print (car *catalog*))
		  (display slib:tab) (report:print '...)))
      (newline))))

(let ((siv (scheme-implementation-version)))
  (cond ((zero? (string-length siv)))
	((or (not (string? siv)) (char=? #\? (string-ref siv 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))))