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

;;; Make this part of your ~/.scheme.init file.

(define getenv get-environment-variable)

;;; (software-type) should be set to the generic operating system type.
(define (software-type)
  (if (eq? 'unix microcode-id/operating-system) 'unix 'ms-dos))

;;; (scheme-implementation-type) should return the name of the scheme
;;; implementation loading this file.
(define (scheme-implementation-type) 'MITScheme)

;;; (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://swiss.csail.mit.edu/projects/scheme/")

;;; (scheme-implementation-version) should return a string describing
;;; the version the scheme implementation loading this file.
(define (scheme-implementation-version)
  (get-subsystem-version-string "Release"))

(define (mit-scheme-release>= major minor)
  (let ((version (scheme-implementation-version)))
    (let ((components (burst-string version #\. #f))
	  (lose
	   (lambda ()
	     (error "Malformed release version string:" version))))
      (let ((major*
	     (or (and (pair? components)
		      (string->number (car components)))
		 (lose))))
	(or (> major* major)
	    (and (= major* major)
		 (>= (or (and (pair? (cdr components))
			      (string->number (cadr components)))
			 (lose))
		     minor)))))))

;;; (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 "MITSCHEME_IMPLEMENTATION_PATH")
	     (->namestring (system-library-directory-pathname #f)))))
    (lambda () impl-path)))

;;; (library-vicinity) should be defined to be the pathname of the
;;; directory where files of Scheme library functions reside.
(define library-vicinity
  (let ((library-path
	 (or (getenv "SCHEME_LIBRARY_PATH")
	     ;; Use this path if your scheme does not support GETENV.
	     (case (software-type)
	       ((ms-dos) "c:\\slib\\")
	       ((unix) "/usr/local/lib/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)
  (->namestring (user-homedir-pathname)))
;@
(define (in-vicinity vicinity file-name)
  (->namestring (merge-pathnames file-name vicinity)))
;@
(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

; **** no, for several reasons
;;;	r5rs				;conforms to
; **** no -- special arguments not supported
;;;	eval				;R5RS two-argument eval
; **** sort of -- not integrated with continuations
	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
; **** no -- #F and '() are identical
;;;	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
	string-port			;has CALL-WITH-INPUT-STRING and
					;CALL-WITH-OUTPUT-STRING
	sort
	pretty-print
	object->string
; **** limited subset with (load-option 'format)
;;;	format				;Common-lisp output formatting
	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

	fluid-let
	queue
	Xwindows
	))

; **** MIT Scheme has SORT, but SORT! accepts only vectors.
(define sort! sort)

(define mit-scheme-has-r4rs-macros?
  (mit-scheme-release>= 7 7))
(if mit-scheme-has-r4rs-macros?
    (set! slib:features (cons 'macro slib:features)))

(if (get-subsystem-version-string "6.001")
    ;; Runs code from "Structure and Interpretation of Computer
    ;; Programs" by Abelson and Sussman.
    (set! slib:features (cons 'sicp slib:features)))

(define current-time current-file-time)
(define difftime -)
(define offset-time +)

;;@ (FILE-POSITION <port> . <k>)
(define (file-position port . args)
  (if (null? args)
      (port-position port)
      (apply set-port-position! port args)))

;;; (OUTPUT-PORT-WIDTH <port>)
(define output-port-width output-port/x-size)

;;; (OUTPUT-PORT-HEIGHT <port>)
(define (output-port-height port)
  (or (output-port/y-size port)
      24))

;;; (CURRENT-ERROR-PORT)
(define current-error-port nearest-cmdl/port)

;;; (TMPNAM) makes a temporary file name.
(define (tmpnam)
  (->namestring (temporary-file-pathname)))

;;; FORCE-OUTPUT flushes any pending output on optional arg output port.
(define force-output flush-output)
;;; MITScheme 7.2 is missing flush-output.  Use this instead
;(define (force-output . arg) #t)

;;; CALL-WITH-INPUT-STRING and CALL-WITH-OUTPUT-STRING are the string
;;; port versions of CALL-WITH-*PUT-FILE.
(define call-with-output-string with-string-output-port)

(define (call-with-input-string string proc)
  (proc (string->input-port string)))

(define (make-exchanger obj)
  (lambda (rep) (let ((old obj)) (set! obj rep) old)))
(define (open-file filename modes)
  (case modes
    ((r) (open-input-file filename))
    ((r+) (open-i/o-file filename))
    ((w) (open-output-file filename))
    ((rb) (open-binary-input-file filename))
    ((r+b rb+) (open-binary-i/o-file filename))
    ((wb) (open-binary-output-file 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 object->string write-to-string)
(define object->limited-string write-to-string)

;;; "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.
;;;
;;; [Note that this definition conflicts with MIT Scheme's definition
;;; of the same name.]
;;;
;;; Can't use correct value because "jacal/types.scm" assumes that
;;; every possible character can be stored into a string.  In MIT
;;; Scheme, only 8-bit characters fit in strings, while the character
;;; object supports 16 bits of character code with 5 bucky bits.  So
;;; instead provide the limit that is appropriate for string
;;; characters.
(define char-code-limit
  ;;char-integer-limit
  256)

;;; MOST-POSITIVE-FIXNUM is used in modular.scm
(define most-positive-fixnum
  (let loop ((n 1))
    (if (fix:fixnum? n)
	(loop (* n 2))
	(- n 1))))

;;; Return argument
(define identity identity-procedure)

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

(define *macros* '(defmacro))
(define (defmacro? m) (and (memq m *macros*) #t))

(if mit-scheme-has-r4rs-macros?
    (environment-define-macro user-initial-environment 'defmacro
      (non-hygienic-macro-transformer->expander
       (lambda arguments
	 (let ((name (car arguments)))
	   `(begin
	      (set! *macros* (cons ',name *macros*))
	      (environment-define-macro user-initial-environment ',name
		(non-hygienic-macro-transformer->expander
		 (lambda ,@(cdr arguments))
		 user-initial-environment)))))
       user-initial-environment))
    (syntax-table-define system-global-syntax-table 'defmacro
      (macro defmacargs
	(let ((macname (car defmacargs)) (macargs (cadr defmacargs))
					 (macbdy (cddr defmacargs)))
	  `(begin
	     (set! *macros* (cons ',macname *macros*))
	     (syntax-table-define system-global-syntax-table ',macname
	       (macro ,macargs ,@macbdy)))))))

(define macroexpand-1)
(define macroexpand)
(let ((finish
       (lambda (get-transformer apply-transformer)
	 (set! macroexpand-1
	       (lambda (form)
		 (let ((transformer (get-transformer form)))
		   (if transformer
		       (apply-transformer transformer form)
		       form))))
	 (set! macroexpand
	       (lambda (form)
		 (let ((transformer (get-transformer form)))
		   (if transformer
		       (macroexpand (apply-transformer transformer form))
		       form)))))))
  (if mit-scheme-has-r4rs-macros?
      (let ((e (->environment '(runtime syntactic-closures))))
	(let ((strip-keyword-value-item (access strip-keyword-value-item e))
	      (expander-item/expander (access expander-item/expander e))
	      (expander-item/environment (access expander-item/environment e)))
	  (finish
	   (lambda (form)
	     (and (pair? form)
		  (let ((a (car form)))
		    (and (symbol? a)
			 (defmacro? a)
			 (environment-lookup-macro user-initial-environment
						   a)))))
	   (lambda (item form)
	     (let ((item (strip-keyword-value-item item)))
	       ((expander-item/expander item)
		form
		user-initial-environment
		(expander-item/environment item)))))))
      (finish
       (lambda (form)
	 (and (pair? form)
	      (let ((a (car form)))
		(and (symbol? a)
		     (defmacro? a)
		     (syntax-table-ref system-global-syntax-table a)))))
       (apply-transformer
	(lambda (transformer form)
	  (apply transformer (cdr form)))))))

(define gentemp generate-uninterned-symbol)

(define defmacro:eval slib:eval)
(define defmacro:load load)
(if mit-scheme-has-r4rs-macros?
    (begin
      (environment-define (the-environment) 'macro:eval slib:eval)
      (environment-define (the-environment) 'macro:load load)))

;; Older implementations need this definition.
(if (lexical-unreferenceable? (the-environment) 'record-modifier)
    (local-assignment (the-environment) 'record-modifier record-updater))

(define (slib:warn . args)
  (if (provided? 'trace) (print-call-stack (notification-output-port)))
  (apply warn args))

;; define an error procedure for the library
(define slib:error
  (let ((error error))
    (lambda (first . args)
      (if (provided? 'trace) (print-call-stack (current-error-port)))
      (case first
	((wrong-type-argument) (apply error:wrong-type-argument args))
	((bad-range-argument)  (apply error:bad-range-argument args))
	(else                  (apply error first args))))))

;; define these as appropriate for your system.
(define slib:tab (name->char "tab"))
(define slib:form-feed (name->char "page"))

;;; Define SLIB:EXIT to be the implementation procedure to exit or
;;; return if exiting not supported.
(define slib:exit
  (lambda args
    (cond ((null? args) (exit))
	  ((eqv? #t (car args)) (exit))
	  ((and (number? (car args)) (integer? (car args))) (exit (car args)))
	  (else (exit 1)))))

;;; Here for backward compatability
(define (scheme-file-suffix) ".scm")

;;; (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)

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