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;;;; "printf.scm" Implementation of standard C functions for Scheme
;;; Copyright (C) 1991-1993, 1996 Aubrey Jaffer.
;
;Permission to copy this software, to redistribute it, 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 warrantee 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.
(require 'string-case)
;;; Floating point is not handled yet.
(define (stdio:iprintf out-proc format-string . args)
(define char-count 0)
(define (out c)
(cond ((char? c) (set! char-count (+ 1 char-count)))
(else (set! char-count (+ (string-length c) char-count))))
(out-proc c) #t)
(cond
((not (equal? "" format-string))
(let ((pos -1)
(fl (string-length format-string))
(fc (string-ref format-string 0)))
(define (advance)
(set! pos (+ 1 pos))
(cond ((>= pos fl) (set! fc #f))
(else (set! fc (string-ref format-string pos)))))
(define (must-advance)
(set! pos (+ 1 pos))
(cond ((>= pos fl) (incomplete))
(else (set! fc (string-ref format-string pos)))))
(define (end-of-format?)
(>= pos fl))
(define (incomplete)
(slib:error 'printf "conversion specification incomplete"
format-string))
(let loop ((args args))
(advance)
(cond
((end-of-format?))
((eqv? #\\ fc);;Emulating C strings may not be a good idea.
(must-advance)
(case fc
((#\n #\N) (out #\newline))
((#\t #\T) (out slib:tab))
((#\r #\R) (out #\return))
((#\f #\F) (out slib:form-feed))
((#\newline) #f)
(else (out fc)))
(loop args))
((eqv? #\% fc)
(must-advance)
(let ((left-adjust #f) ;-
(signed #f) ;+
(blank #f)
(alternate-form #f) ;#
(leading-0s #f) ;0
(width 0)
(precision -1)
(type-modifier #f)
(read-format-number
(lambda ()
(cond
((eqv? #\* fc) ; GNU extension
(must-advance)
(let ((ans (car args)))
(set! args (cdr args))
ans))
(else
(do ((c fc fc)
(accum 0 (+ (* accum 10)
(string->number (string c)))))
((not (char-numeric? fc)) accum)
(must-advance)))))))
(define integer-pad
(lambda (s radix)
(cond ((not (negative? precision))
(set! leading-0s #f)))
(let* ((pre
(cond ((equal? "" s) "")
((eqv? #\- (string-ref s 0))
(set! s (substring s 1 (string-length s)))
"-")
(signed "+")
(blank " ")
((equal? "" s) "")
(alternate-form
(case radix
((8) "0")
((16) "0x")
(else "")))
(else "")))
(length-so-far (+ (string-length pre)
(string-length s))))
(cond ((<= width length-so-far)
(string-append pre s))
(left-adjust
(string-append
pre s
(make-string (- width length-so-far) #\ )))
(leading-0s
(string-append
pre (make-string (- width length-so-far) #\0)
s))
(else
(string-append
(make-string (- width length-so-far) #\ )
pre s))))))
(do ()
((case fc
((#\-) (set! left-adjust #t) #f)
((#\+) (set! signed #t) #f)
((#\ ) (set! blank #t) #f)
((#\#) (set! alternate-form #t) #f)
((#\0) (set! leading-0s #t) #f)
(else #t)))
(must-advance))
(cond (left-adjust (set! leading-0s #f)))
(cond (signed (set! blank #f)))
(set! width (read-format-number))
(cond ((negative? width)
(set! left-adjust #t)
(set! width (- width))))
(cond ((eqv? #\. fc)
(must-advance)
(set! precision (read-format-number))))
(case fc ;Ignore these specifiers
((#\l #\L #\h)
(set! type-modifier fc)
(must-advance)))
(case fc
;; only - is allowed between % and c
((#\c #\C) ; C is enhancement
(out (string (car args)))
(loop (cdr args)))
;; only - flag, no type-modifiers
((#\s #\S) ; S is enhancement
(let ((s (cond
((symbol? (car args)) (symbol->string (car args)))
((not (car args)) "(NULL)")
(else (car args)))))
(cond ((not (or (negative? precision)
(>= precision (string-length s))))
(set! s (substring s 0 precision))))
(out
(cond
((<= width (string-length s)) s)
(left-adjust
(string-append
s (make-string (- width (string-length s)) #\ )))
(else
(string-append (make-string (- width (string-length s))
(if leading-0s #\0 #\ )) s))))
(loop (cdr args))))
;; SLIB extension
((#\a #\A) ;#\y #\Y are pretty-print
(require 'generic-write)
(let ((os "") (pr precision))
(generic-write
(car args) (not alternate-form) #f
(cond ((and left-adjust (negative? pr))
out)
(left-adjust
(lambda (s)
(define sl (- pr (string-length s)))
(set! pr (cond ((negative? sl)
(out (substring s 0 pr)) 0)
(else (out s) sl)))
(positive? sl)))
((negative? pr)
(set! pr width)
(lambda (s)
(set! pr (- pr (string-length s)))
(cond ((not os) (out s))
((negative? pr)
(out os)
(set! os #f)
(out s))
(else (set! os (string-append os s))))
#t))
(else
(lambda (s)
(define sl (- pr (string-length s)))
(cond ((negative? sl)
(set! os (string-append
os (substring s 0 pr))))
(else (set! os (string-append os s))))
(set! pr sl)
(positive? sl)))))
(cond (left-adjust
(cond
((> width (- precision pr))
(out (make-string (- width (- precision pr))
#\ )))))
((not os))
((<= width (string-length os)) (out os))
(else
(out (make-string (- width (string-length os)) #\ ))
(out os))))
(loop (cdr args)))
((#\d #\D #\i #\I #\u #\U)
(out (integer-pad
(cond ((symbol? (car args))
(symbol->string (car args)))
((number? (car args))
(number->string (car args)))
((not (car args)) "0")
(else "1"))
10))
(loop (cdr args)))
((#\o #\O)
(out (integer-pad (number->string (car args) 8) 8))
(loop (cdr args)))
((#\x #\X)
(out
((if (char-upper-case? fc) string-upcase string-downcase)
(integer-pad (number->string (car args) 16) 16)))
(loop (cdr args)))
((#\%) (out #\%)
(loop args))
(else
(cond ((end-of-format?) (incomplete))
(else (out #\%) (out fc) (out #\?)
(loop args)))))))
(else (out fc)
(loop args)))))))
char-count) ; return number of characters output.
(define (stdio:printf format . args)
(apply stdio:iprintf display format args))
(define (stdio:fprintf port format . args)
(if (equal? port (current-output-port))
(apply stdio:iprintf display format args)
(apply stdio:iprintf (lambda (x) (display x port)) format args)))
(define (stdio:sprintf s format . args)
(let ((p 0) (end (string-length s)))
(apply stdio:iprintf
(lambda (x)
(cond ((string? x)
(do ((i 0 (+ i 1)))
((>= i (min (string-length x) end)))
(string-set! s p (string-ref x i))
(set! p (+ p 1))))
((>= p end))
((char? x)
(string-set! s p x)
(set! p (+ p 1)))
(else
(string-set! s p #\?)
(set! p (+ p 1)))))
format
args)
p))
(define printf stdio:printf)
(define fprintf stdio:fprintf)
(define sprintf stdio:sprintf)
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