;;;"chez.init" Initialization file for SLIB for Chez Scheme 6.0a -*-scheme-*-
;;; Authors: dorai@cs.rice.edu (Dorai Sitaram) and Aubrey Jaffer.
;;;
;;; This code is in the public domain.

;;; Adapted to version 5.0c by stone@math.grin.edu (John David Stone) 1997
;;; Adapted to version 6.0a by Gary T. Leavens <leavens@cs.iastate.edu>, 1999

;;; (software-type) should be set to the generic operating system type.
;;; UNIX, VMS, MACOS, AMIGA and MS-DOS are supported.

(define (software-type) 'UNIX)

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

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

;;; (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.cs.indiana.edu/chezscheme/")

;;; (scheme-implementation-version) should return a string describing
;;; the version the scheme implementation loading this file.

(define (scheme-implementation-version) "6.0a")

;;; (implementation-vicinity) should be defined to be the pathname of
;;; the directory where any auxillary files to your Scheme
;;; implementation reside.

(define implementation-vicinity
  (lambda () "/usr/unsup/scheme/chez/"))

;;; (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
	  ;; 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/")
	    ((VMS) "lib$scheme:")
	    ((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-path (getenv "HOME")))
    (lambda () home-path)))

;;; *FEATURES* should be set to a list of symbols describing features
;;; of this implementation.  Suggestions for features are:

(define *features*
      '(
	source				;can load scheme source files
					;(slib:load-source "filename")
	compiled			;can load compiled files
					;(slib:load-compiled "filename")

		       ;; Scheme report features

	rev5-report			;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?
	rationalize
	rev4-optional-procedures	;LIST-TAIL, STRING->LIST,
					;LIST->STRING, STRING-COPY,
					;STRING-FILL!, LIST->VECTOR,
					;VECTOR->LIST, and VECTOR-FILL!

	rev4-report			;conforms to

	ieee-p1178			;conforms to

	rev3-report			;conforms to

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

	multiarg/and-			;/ and - can take more than 2 args.
	with-file			;has WITH-INPUT-FROM-FILE and
					;WITH-OUTPUT-FROM-FILE
	transcript			;TRANSCRIPT-ON and TRANSCRIPT-OFF
;	ieee-floating-point		;conforms to IEEE Standard 754-1985
					;IEEE Standard for Binary
					;Floating-Point Arithmetic.
	full-continuation		;can return multiple times

			;; Other common features

;	srfi				;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
	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
	random
	))

;;; (OUTPUT-PORT-WIDTH <port>) returns the number of graphic characters
;;; that can reliably be displayed on one line of the standard output port.

(define output-port-width
  (lambda arg
    (let ((env-width-string (getenv "COLUMNS")))
      (if (and env-width-string
	       (let loop ((remaining (string-length env-width-string)))
		 (or (zero? remaining)
		     (let ((next (- remaining 1)))
		       (and (char-numeric? (string-ref env-width-string
						       next))
			    (loop next))))))
	  (- (string->number env-width-string) 1)
	  79))))

;;; (OUTPUT-PORT-HEIGHT <port>) returns the number of lines of text that
;;; can reliably be displayed simultaneously in the standard output port.

(define output-port-height
  (lambda arg
    (let ((env-height-string (getenv "LINES")))
      (if (and env-height-string
	       (let loop ((remaining (string-length env-height-string)))
		 (or (zero? remaining)
		     (let ((next (- remaining 1)))
		       (and (char-numeric? (string-ref env-height-string
						       next))
			    (loop next))))))
	  (string->number env-height-string)
	  24))))

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

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

;;; (FILE-EXISTS? <string>) is built-in to Chez Scheme

;;; (DELETE-FILE <string>) is built-in to Chez Scheme

;; The FORCE-OUTPUT requires buffered output that has been written to a
;; port to be transferred all the way out to its ultimate destination.
(define force-output flush-output-port)

;;; "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
;; Chez's MOST-POSITIVE-FIXNUM is a thunk rather than a number.

(if (procedure? most-positive-fixnum)
    (set! most-positive-fixnum (most-positive-fixnum)))

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

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

;;; define an error procedure for the library
(define slib:error
  (lambda args
    (let ((cep (current-error-port)))
      (if (provided? 'trace) (print-call-stack cep))
      (display "Error: " cep)
      (for-each (lambda (x) (display x cep)) args)
      (error #f ""))))

;;; define these as appropriate for your system.
(define slib:tab #\tab)
(define slib:form-feed #\page)

;;; Support for older versions of Scheme.  Not enough code for its own file.
;;; last-pair is built-in to Chez Scheme
(define t #t)
(define nil #f)

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

;;; (IN-VICINITY <string>) is simply STRING-APPEND, conventionally used
;;; to attach a directory pathname to the name of a file that is expected to
;;; be in that directory.
(define in-vicinity string-append)

;;; Define SLIB:EXIT to be the implementation procedure to exit or
;;; return if exitting not supported.
(define slib:chez:quit
  (let ((arg (call-with-current-continuation identity)))
    (cond ((procedure? arg) arg)
	  (arg (exit))
	  (else (exit 1)))))

(define slib:exit
  (lambda args
    (cond ((null? args) (slib:chez:quit #t))
	  ((eqv? #t (car args)) (slib:chez:quit #t))
	  ((eqv? #f (car args)) (slib:chez:quit #f))
	  ((zero? (car args)) (slib:chez:quit #t))
	  (else (slib:chez:quit #f)))))

;;; For backward compatability, the SCHEME-FILE-SUFFIX procedure is defined
;;; to return the string ".scm".  Note, however, that ".ss" is a common Chez
;;; file suffix.
(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 f) (load (string-append f ".scm")))

;;; (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)

;;; The following make procedures in Chez Scheme compatible with
;;; the assumptions of SLIB.

;;; Chez's sorting routines take parameters in the order opposite to SLIB's.
;;; The following definitions override the predefined procedures with the
;;; parameters-reversed versions.  See the SORT feature.

(define chez:sort sort)
(define chez:sort! sort!)
(define chez:merge merge)
(define chez:merge! merge!)

(define sort
  (lambda (s p)
    (chez:sort p s)))
(define sort!
  (lambda (s p)
    (chez:sort! p s)))
(define merge
  (lambda (s1 s2 p)
    (chez:merge p s1 s2)))
(define merge!
  (lambda (s1 s2 p)
    (chez:merge! p s1 s2)))

;;; Chez's (FORMAT F . A) corresponds to SLIB's (FORMAT #F F . A)
;;; See the FORMAT feature.

(define chez:format format)

(define format
  (lambda (where how . args)
    (let ((str (apply chez:format how args)))
      (cond ((not where) str)
	    ((eq? where #t) (display str))
	    (else (display str where))))))

;; The following definitions implement a few widely useful procedures that
;; Chez Scheme does not provide or provides under a different name.

;;; CALL-WITH-INPUT-STRING and CALL-WITH-OUTPUT-STRING are the string
;;; port versions of CALL-WITH-INPUT-FILE and CALL-WITH-OUTPUT-FILE.
;;; See the STRING-PORT feature.

(define call-with-output-string
  (lambda (f)
    (let ((outsp (open-output-string)))
      (f outsp)
      (let ((s (get-output-string outsp)))
	(close-output-port outsp)
	s))))

(define call-with-input-string
  (lambda (s f)
    (let* ((insp (open-input-string s))
	   (res (f insp)))
      (close-input-port insp)
      res)))

;;; If your implementation provides R4RS macros:
(define macro:eval slib:eval)
;;; macro:load also needs the default suffix.
(define macro:load slib:load-source)

(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))

;;; According to Kent Dybvig, you can improve the Chez Scheme init
;;; file by defining gentemp to be gensym in Chez Scheme.
(define gentemp gensym)

(define base:eval slib:eval)
(define (defmacro:eval x) (base:eval (defmacro:expand* x)))
(define (defmacro:expand* x)
  (require 'defmacroexpand) (apply defmacro:expand* x '()))

(define (slib:eval-load <pathname> evl)
  (if (not (file-exists? <pathname>))
      (set! <pathname> (string-append <pathname> (scheme-file-suffix))))
  (call-with-input-file <pathname>
    (lambda (port)
      (let ((old-load-pathname *load-pathname*))
	(set! *load-pathname* <pathname>)
	(do ((o (read port) (read port)))
	    ((eof-object? o))
	  (evl o))
	(set! *load-pathname* old-load-pathname)))))

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

(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 x cep)) args))))

;;; Load the REQUIRE package.

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

;; end of chez.init