gambit.init

;;;"gambit.init" Initialization for SLIB for Gambit	-*-scheme-*-
;;; Author: Aubrey Jaffer
;;;
;;; This code is in the public domain.

;;; Updated 1992 February 1 for Gambit v1.71 -- by Ken Dickey
;;; Date: Wed, 12 Jan 1994 15:03:12 -0500
;;; From: barnett@armadillo.urich.edu (Lewis Barnett)
;;; Relative pathnames for Slib in MacGambit
;;; Hacked yet again for Gambit v2.4, Jan 1997, by Mike Pope
;;; Updated for Gambit v3.0, 2001-01 AGJ.
;;; Major update for Gambit-C 4.0b12. 2005-01 AGJ.

;;; gsi should be invoked with -:s option to Ignore case when reading
;;; symbols (per R5RS).

(define (software-type) 'macos)		; for MacGambit.
(define (software-type) 'unix)		; for Unix platforms.

(define (scheme-implementation-type) 'gambit)

;;; (scheme-implementation-home-page) should return a (string) URI
;;; (Uniform Resource Identifier) for this scheme implementation's home
;;; page; or false if there isn't one.
(define (scheme-implementation-home-page)
  "http://www.iro.umontreal.ca/~gambit/index.html")

(define (scheme-implementation-version) (system-version-string))

(define getenv
  (let ((ge getenv))
    (lambda (str) (ge str #f))))

;;; (implementation-vicinity) should be defined to be the pathname of
;;; the directory where any auxillary files to your Scheme
;;; implementation reside.
(define implementation-vicinity
  (let ((impl-path
	 (or (getenv "GAMBIT_IMPLEMENTATION_PATH")
	     (case (software-type)
	       ((unix) "/usr/local/share/gambc/")
	       ((vms) "scheme$src:")
	       ((ms-dos) "C:\\scheme\\")
	       ((windows) "c:/scheme/")
	       ((macos)
		(let ((arg0 (list-ref (argv) 0)))
		  (let loop ((i (- (string-length arg0) 1)))
		    (cond ((negative? i) "")
			  ((char=? #\: (string-ref arg0 i))
			   (substring arg0 0 (+ i 1)))
			  (else (loop (- i 1)))))))
	       (else "")))))
    (lambda () impl-path)))

;;; (library-vicinity) should be defined to be the pathname of the
;;; directory where files of Scheme library functions reside.
;;;
;;; This assumes that the slib files are in a folder
;;; called slib in the same directory as the MacGambit Interpreter.
(define library-vicinity
  (let ((library-path
	 (or
	  ;; Use this getenv if your implementation supports it.
	  (getenv "SCHEME_LIBRARY_PATH")
	  ;; Use this path if your scheme does not support GETENV
	  ;; or if SCHEME_LIBRARY_PATH is not set.
	  (case (software-type)
	    ((unix) "/usr/local/lib/slib/")
	    ((macos) (string-append (implementation-vicinity) "slib:"))
	    ((amiga) "dh0:scm/Library/")
	    ((vms) "lib$scheme:")
	    ((windows ms-dos) "C:\\SLIB\\")
	    (else "")))))
    (lambda () library-path)))

;;; (home-vicinity) should return the vicinity of the user's HOME
;;; directory, the directory which typically contains files which
;;; customize a computer environment for a user.
(define (home-vicinity)
  (let ((home (getenv "HOME")))
    (if home
	(case (software-type)
	  ((unix coherent ms-dos)	;V7 unix has a / on HOME
	   (if (eqv? #\/ (string-ref home (+ -1 (string-length home))))
	       home
	       (string-append home "/")))
	  (else home))
	(case (software-type)
	  ((vms)      "~:")
	  ((windows)  "~/")
	  ((macos)    "~:")
	  (else #f)))))
;@
(define in-vicinity string-append)
;@
(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)				'(#\: #\]))
	   (else
	    (slib:warn "require.scm" 'unknown 'software-type (software-type))
	    "/"))))
    (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 with-load-pathname
  (let ((exchange
	 (lambda (new)
	   (let ((old *load-pathname*))
	     (set! *load-pathname* new)
	     old))))
    (lambda (path thunk)
      (let ((old #f))
	(dynamic-wind
	    (lambda () (set! old (exchange path)))
	    thunk
	    (lambda () (exchange old)))))))

;;@ SLIB:FEATURES is a list of symbols naming the (SLIB) features
;;; initially supported by this implementation.
(define slib:features
      '(
	source				;can load scheme source files
					;(SLIB:LOAD-SOURCE "filename")
	compiled			;can load compiled files
					;(SLIB:LOAD-COMPILED "filename")
	vicinity
	srfi-59
	srfi-96

		       ;; Scheme report features
   ;; R5RS-compliant implementations should provide all 9 features.

;;;	r5rs				;conforms to
;;;	eval				;R5RS two-argument eval
	values				;R5RS multiple values
	dynamic-wind			;R5RS dynamic-wind
;;;	macro				;R5RS high level macros
	delay				;has DELAY and FORCE
	multiarg-apply			;APPLY can take more than 2 args.
	char-ready?
	rev4-optional-procedures	;LIST-TAIL, STRING-COPY,
					;STRING-FILL!, and VECTOR-FILL!

      ;; These four features are optional in both R4RS and R5RS

	multiarg/and-			;/ and - can take more than 2 args.
	rationalize
	transcript			;TRANSCRIPT-ON and TRANSCRIPT-OFF
	with-file			;has WITH-INPUT-FROM-FILE and
					;WITH-OUTPUT-TO-FILE

	r4rs				;conforms to

	ieee-p1178			;conforms to

;;;	r3rs				;conforms to

;;;	rev2-procedures			;SUBSTRING-MOVE-LEFT!,
					;SUBSTRING-MOVE-RIGHT!,
					;SUBSTRING-FILL!,
					;STRING-NULL?, APPEND!, 1+,
					;-1+, <?, <=?, =?, >?, >=?
;;;	object-hash			;has OBJECT-HASH

	full-continuation		;can return multiple times
	ieee-floating-point		;conforms to IEEE Standard 754-1985
					;IEEE Standard for Binary
					;Floating-Point Arithmetic.

			;; Other common features

	srfi-0				;srfi-0, COND-EXPAND finds all srfi-*
	sicp				;runs code from Structure and
					;Interpretation of Computer
					;Programs by Abelson and Sussman.
	defmacro			;has Common Lisp DEFMACRO
;;;	record				;has user defined data structures
	structure			;DEFINE-STRUCTURE macro
	string-port			;has CALL-WITH-INPUT-STRING and
					;CALL-WITH-OUTPUT-STRING
;;;	sort
	pretty-print
	object->string
;;;	format
	trace				;has macros: TRACE and UNTRACE
;;;	compiler			;has (COMPILER)
;;;	ed				;(ED) is editor
	system				;posix (system <string>)
	getenv				;posix (getenv <string>)
;;;	program-arguments		;returns list of strings (argv)
	current-time			;returns time in seconds since 1/1/1970

		  ;; Implementation Specific features

	break

	))

(define object->limited-string object->string)

(define (difftime caltime1 caltime0)
  (- (time->seconds caltime1)
     (if (number? caltime0) caltime0 (time->seconds caltime0))))
(define (offset-time caltime offset)
  (seconds->time (+ (time->seconds caltime) offset)))

;; procedure: input-port-byte-position port [position [whence]]
;; procedure: output-port-byte-position port [position [whence]]
;;
;;     When called with a single argument these procedures return the
;; byte position where the next I/O operation would take place in the
;; file attached to the given port (relative to the beginning of the
;; file).  When called with two or three arguments, the byte position
;; for subsequent I/O operations on the given port is changed to
;; position, which must be an exact integer.  When whence is omitted
;; or is 0, the position is relative to the beginning of the file.
;; When whence is 1, the position is relative to the current byte
;; position of the file.  When whence is 2, the position is relative
;; to the end of the file.  The return value is the new byte position.
;; On most operating systems the byte position for reading and writing
;; of a given bidirectional port are the same.
;;
;;     When input-port-byte-position is called to change the byte
;; position of an input-port, all input buffers will be flushed so
;; that the next byte read will be the one at the given position.
;;
;;     When output-port-byte-position is called to change the byte
;; position of an output-port, there is an implicit call to
;; force-output before the position is changed.

;;@ (FILE-POSITION <port> . <k>)
(define (file-position port . k)
  (apply (if (output-port? port)
	     output-port-byte-position
	     input-port-byte-position)
	 port
	 k))

;;; (OUTPUT-PORT-WIDTH <port>)
;; (define (output-port-width . arg) 79)

;;; (OUTPUT-PORT-HEIGHT <port>)
(define (output-port-height . arg) 24)

;;; (CURRENT-ERROR-PORT)
(define current-error-port
  (let ((port (current-output-port)))
    (lambda () port)))

;;; (TMPNAM) makes a temporary file name.
(define tmpnam (let ((cntr 100))
		 (lambda () (set! cntr (+ 1 cntr))
			 (string-append "slib_" (number->string cntr)))))

;;; Gambit supports SYSTEM as an "Unstable Addition"; Watch for changes.
(define system ##shell-command)

;;; CALL-WITH-INPUT-STRING is good as is.  Gambit's
;;; CALL-WITH-OUTPUT-STRING lengthens the string first argument.
(define call-with-output-string
  (let ((cwos call-with-output-string))
    (lambda (proc) (cwos "" proc))))

(define (make-exchanger obj)
  (lambda (rep) (let ((old obj)) (set! obj rep) old)))
(define open-file
  (let ((open-both open-file))
    (lambda (filename modes)
      (case modes
	((r rb) (open-input-file filename))
	((w wb) (open-output-file filename))
	((rw rwb) (open-both filename))
	(else (slib:error 'open-file 'mode? modes))))))
(define (call-with-open-ports . ports)
  (define proc (car ports))
  (cond ((procedure? proc) (set! ports (cdr ports)))
	(else (set! ports (reverse ports))
	      (set! proc (car ports))
	      (set! ports (reverse (cdr ports)))))
  (let ((ans (apply proc ports)))
    (for-each close-port ports)
    ans))

(define (browse-url url)
  (define (try cmd) (eqv? 0 (system (sprintf #f cmd url))))
  (or (try "netscape-remote -remote 'openURL(%s)'")
      (try "netscape -remote 'openURL(%s)'")
      (try "netscape '%s'&")
      (try "netscape '%s'")))

;;; "rationalize" adjunct procedures.
(define (find-ratio x e)
  (let ((rat (rationalize x e)))
    (list (numerator rat) (denominator rat))))
(define (find-ratio-between x y)
  (find-ratio (/ (+ x y) 2) (/ (- x y) 2)))

;;; CHAR-CODE-LIMIT is one greater than the largest integer which can
;;; be returned by CHAR->INTEGER.
(define char-code-limit 256)

;; MOST-POSITIVE-FIXNUM is used in modular.scm
(define most-positive-fixnum #x1FFFFFFF) ; 3-bit tag for 68K

;;; Return argument
(define (identity x) x)

;;; SLIB:EVAL is single argument eval using the top-level (user) environment.
(define slib:eval eval)

(define *defmacros*
  (list (cons 'defmacro
	      (lambda (name parms . body)
		`(set! *defmacros* (cons (cons ',name (lambda ,parms ,@body))
					 *defmacros*))))))
(define (defmacro? m) (and (assq m *defmacros*) #t))

(define (macroexpand-1 e)
  (if (pair? e) (let ((a (car e)))
		  (cond ((symbol? a) (set! a (assq a *defmacros*))
				     (if a (apply (cdr a) (cdr e)) e))
			(else e)))
      e))

(define (macroexpand e)
  (if (pair? e) (let ((a (car e)))
		  (cond ((symbol? a)
			 (set! a (assq a *defmacros*))
			 (if a (macroexpand (apply (cdr a) (cdr e))) e))
			(else e)))
      e))

(define gentemp
  (let ((*gensym-counter* -1))
    (lambda ()
      (set! *gensym-counter* (+ *gensym-counter* 1))
      (string->symbol
       (string-append "slib:G" (number->string *gensym-counter*))))))

(define base:eval slib:eval)
(define defmacro:eval base:eval)

(define (defmacro:load <pathname>)
  (slib:eval-load <pathname> defmacro:eval))

(define print-call-stack identity)	;noop

(define slib:warn
  (lambda args
    (let ((cep (current-error-port)))
      (if (provided? 'trace) (print-call-stack cep))
      (display "Warn: " cep)
      (for-each (lambda (x) (display #\space cep) (write x cep)) args))))

;; define an error procedure for the library
(define slib:error
  (let ((error error))
    (lambda args
      (if (provided? 'trace) (print-call-stack (current-error-port)))
      (apply error args))))

;; define these as appropriate for your system.
(define slib:tab (integer->char 9))
(define slib:form-feed (integer->char 12))

;;; Support for older versions of Scheme.  Not enough code for its own file.
(define (last-pair l) (if (pair? (cdr l)) (last-pair (cdr l)) l))
(define t #t)
(define nil #f)

;;; Define these if your implementation's syntax can support it and if
;;; they are not already defined.
(define (1+ n) (+ n 1))
(define (-1+ n) (- n 1))
(define 1- -1+)

;;; Define SLIB:EXIT to be the implementation procedure to exit or
;;; return if exiting not supported.
(define slib:exit (lambda args (exit)))

;;; Here for backward compatability
(define scheme-file-suffix
  (let ((suffix (case (software-type)
		  ((nosve) "_scm")
		  (else ".scm"))))
    (lambda () suffix)))

;;; (SLIB:LOAD-SOURCE "foo") should load "foo.scm" or with whatever
;;; suffix all the module files in SLIB have.  See feature 'SOURCE.
(define slib:load-source load)

;;; (SLIB:LOAD-COMPILED "foo") should load the file that was produced
;;; by compiling "foo.scm" if this implementation can compile files.
;;; See feature 'COMPILED.
(define slib:load-compiled load)

;;; At this point SLIB:LOAD must be able to load SLIB files.
(define slib:load slib:load-source)

;;; If your implementation provides R4RS macros:
;;(define macro:eval slib:eval)
;;(define macro:load slib:load-source)

;;; If your implementation provides syntax-case macros:
;;(define syncase:eval slib:eval)
;;(define syncase:load slib:load-source)

(slib:eval '(define-macro (defmacro name parms . body)
	      (set! *defmacros* (cons `(cons ',name (lambda ,parms ,@body))
				      *defmacros*))
	      `(define-macro (,name ,@parms) ,@body)))

(slib:load (in-vicinity (library-vicinity) "require"))