;;; "Template.scm" configuration template of *features* for Scheme -*-scheme-*-
;;; Author: Aubrey Jaffer
;;;
;;; This code is in the public domain.

;;@ (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) 'Template)

;;@ (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) #f)

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

;;@ (implementation-vicinity) should be defined to be the pathname of
;;; the directory where any auxillary files to your Scheme
;;; implementation reside.
(define (implementation-vicinity)
  (case (software-type)
    ((UNIX)	"/usr/local/src/scheme/")
    ((VMS)	"scheme$src:")
    ((MS-DOS)	"C:\\scheme\\")))

;;@ (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 (getenv "HOME")))
    (and 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)))))

;;@ *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

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

	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

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

	))

;;@ (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)))))

;;@ (FILE-EXISTS? <string>)
(define (file-exists? f) #f)

;;@ (DELETE-FILE <string>)
(define (delete-file f) #f)

;;@ FORCE-OUTPUT flushes any pending output on optional arg output port
;;; use this definition if your system doesn't have such a procedure.
(define (force-output . arg) #t)

;;; CALL-WITH-INPUT-STRING and CALL-WITH-OUTPUT-STRING are the string
;;; port versions of CALL-WITH-*PUT-FILE.

;;@ "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 #x0FFFFFFF)

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

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

;; If your implementation provides R4RS macros:
;(define macro:eval slib:eval)
;(define macro:load load)
(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 x) (base:eval (defmacro:expand* x)))

(define (defmacro:expand* x)
  (require 'defmacroexpand) (apply defmacro:expand* x '()))
;@
(define (defmacro:load <pathname>)
  (slib:eval-load <pathname> defmacro:eval))
;@
(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 slib:warn
  (lambda args
    (let ((cep (current-error-port)))
      (if (provided? 'trace) (print-call-stack cep))
      (display "Warn: " cep)
      (for-each (lambda (x) (display #\  cep) (write x cep)) args))))

;;@ define an error procedure for the library
(define (slib:error . args)
  (if (provided? 'trace) (print-call-stack (current-error-port)))
  (apply error args))
;@
(define (make-exchanger obj)
  (lambda (rep) (let ((old obj)) (set! obj rep) old)))
(define (open-file filename modes)
  (case modes
    ((r rb) (open-input-file filename))
    ((w wb) (open-output-file filename))
    (else (slib:error 'open-file 'mode? modes))))
(define (port? obj) (or (input-port? port) (output-port? port)))
(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 (close-port port)
  (cond ((input-port? port)
	 (close-input-port port)
	 (if (output-port? port) (close-output-port port)))
	((output-port? port) (close-output-port port))
	(else (slib:error 'close-port 'port? port))))
;@
(define (browse-url url)
  (define (try cmd end) (zero? (system (string-append cmd url end))))
  (or (try "netscape-remote -remote 'openURL(" ")'")
      (try "netscape -remote 'openURL(" ")'")
      (try "netscape '" "'&")
      (try "netscape '" "'")))

;;@ 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 in-vicinity string-append)

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

;;@ 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 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)

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